---
format:
html:
toc: true
toc-depth: 2
theme: {dark: darkly, light: cosmo}
number-sections: false
number-depth: 0
code-fold: false
code-tools: true
highlight-style: nord
---
<style></style><style>.printedClojure .sourceCode {
background-color: transparent;
border-style: none;
}
</style><style>.clay-limit-image-width .clay-image {max-width: 100%}
.clay-side-by-side .sourceCode {margin: 0}
.clay-side-by-side {margin: 1em 0}
</style>
<script src="https://code.jquery.com/jquery-3.6.0.min.js" type="text/javascript"></script><script src="https://code.jquery.com/ui/1.13.1/jquery-ui.min.js" type="text/javascript"></script>
```{=html}
<div style="display:none;"><style>/* ---------------------------------------------------------------
Fedoras — one palette, two schemes.
Dark is the default. Quarto puts .quarto-light on the body when the
reader flips the toggle, and everything below is written against
these variables, so a scheme change is nine lines rather than three
hundred.
--------------------------------------------------------------- */
:root {
--paper: #1b1d21; /* background */
--ink: #e6e4df; /* text */
--ink-soft: #a9a49b; /* secondary text */
--rule: rgba(230, 228, 223, 0.22);
--panel: rgba(230, 228, 223, 0.05);
--violet: #9d8dff; /* apparatus, epigraphs */
--gold: #d0a44c; /* beats, commits */
--coral: #e2707c; /* moderation, rewrites */
--green: #6fcf9b; /* the Helps */
--blurple: #8b95f0; /* Discord */
--violet-rgb: 157, 141, 255;
--gold-rgb: 208, 164, 76;
--coral-rgb: 226, 112, 124;
--green-rgb: 111, 207, 155;
--blurple-rgb: 139, 149, 240;
--ink-rgb: 168, 164, 156;
--panel-hard: #101215;
}
body.quarto-light {
--paper: #faf8f4;
--ink: #1c1f24;
--ink-soft: #6b665e;
--rule: rgba(28, 31, 36, 0.22);
--panel: rgba(28, 31, 36, 0.05);
--violet: #6c5ce7;
--gold: #b0863a;
--coral: #e04f5f;
--green: #2ea078;
--blurple: #5865f2;
--violet-rgb: 108, 92, 231;
--gold-rgb: 176, 134, 58;
--coral-rgb: 224, 79, 95;
--green-rgb: 46, 160, 120;
--blurple-rgb: 88, 101, 242;
--ink-rgb: 128, 128, 128;
--panel-hard: #14161a;
}
/* ---------------------------------------------------------------
Fedoras — screenplay typography for the HTML edition.
Loaded by fedoras.screenplay/assets. Edit here, rebuild, done.
PDF styling lives in notebooks/tex/fedoras-preamble.tex instead.
--------------------------------------------------------------- */
.screenplay {
font-family: "Courier Prime", "Courier New", ui-monospace, monospace;
font-size: 1rem;
line-height: 1.35;
max-width: 62ch;
margin: 1.6rem 0 2.2rem 0;
}
.screenplay .slug {
font-weight: 700;
letter-spacing: 0.04em;
margin: 1.6rem 0 0.8rem 0;
}
.screenplay .action {
margin: 0 0 0.85rem 0;
}
.action{
white-space: pre-line;
}
.screenplay .action.beat {
margin-bottom: 0.35rem;
}
.screenplay .dialogue {
margin: 0 0 0.95rem 0;
}
.screenplay .character {
margin: 0 0 0 12ch;
font-weight: 700;
letter-spacing: 0.06em;
}
.screenplay .paren {
margin: 0 0 0 9ch;
font-style: italic;
opacity: 0.85;
}
.screenplay .lines {
margin-left: 6ch;
max-width: 50ch;
}
.screenplay .line {
margin: 0;
}
.screenplay .transition {
margin: 1.1rem 0 1.1rem 0;
text-align: right;
font-weight: 700;
letter-spacing: 0.08em;
}
.screenplay .direction {
font-style: italic;
opacity: 0.85;
margin: 0 0 0.9rem 0;
}
/* In-world text: banners, signs, whiteboards. */
.screenplay .sign {
border: 1px solid currentColor;
padding: 0.7rem 1rem;
margin: 0.9rem 0 1.1rem 4ch;
max-width: 46ch;
text-align: center;
letter-spacing: 0.05em;
}
.screenplay .sign p {
margin: 0.15rem 0;
}
.screenplay .whiteboard {
text-align: left;
}
.screenplay .whiteboard-title {
font-weight: 700;
text-transform: uppercase;
margin-bottom: 0.4rem !important;
}
.screenplay .whiteboard ol {
margin: 0;
padding-left: 2.2ch;
}
/* --- The Fedora Handbook epigraphs ------------------------------- */
.handbook {
max-width: 54ch;
margin: 1.4rem 0 2rem 2ch;
padding-left: 1.1rem;
border-left: 3px solid var(--violet);
font-style: italic;
}
.handbook .rule-number {
font-style: normal;
font-variant: small-caps;
letter-spacing: 0.08em;
opacity: 0.75;
margin-bottom: 0.25rem;
}
.handbook .rule-text {
margin: 0;
}
/* --- Drafting apparatus (hidden in the reading copy) -------------- */
.beats {
border: 1px dashed var(--gold);
background: rgba(var(--gold-rgb), 0.07);
padding: 0.6rem 0.9rem;
margin: 1.1rem 0;
max-width: 62ch;
font-size: 0.88rem;
}
.beats-title {
font-variant: small-caps;
letter-spacing: 0.1em;
font-weight: 700;
margin: 0 0 0.35rem 0;
opacity: 0.8;
}
.beats ul {
margin: 0;
padding-left: 1.4rem;
}
.beats.note {
border-color: var(--blurple);
background: rgba(var(--blurple-rgb), 0.07);
}
.status {
display: inline-block;
font-family: ui-monospace, monospace;
font-size: 0.7rem;
letter-spacing: 0.14em;
padding: 0.15rem 0.5rem;
border-radius: 3px;
margin: 0 0 0.8rem 0;
}
.status-outline { background: var(--ink-soft); color: #fff; }
.status-draft { background: var(--gold); color: #fff; }
.status-locked { background: var(--green); color: #fff; }
/* --- Live (editable) code cells ---------------------------------- */
.live-cell {
border: 1px solid rgba(var(--ink-rgb), 0.4);
border-radius: 5px;
padding: 0.7rem 0.8rem;
margin: 1.2rem 0;
max-width: 68ch;
}
.live-label {
font-size: 0.78rem;
letter-spacing: 0.09em;
text-transform: uppercase;
opacity: 0.7;
margin-bottom: 0.45rem;
}
.live-src {
width: 100%;
font-family: ui-monospace, "Courier New", monospace;
font-size: 0.9rem;
line-height: 1.4;
padding: 0.5rem;
border: 1px solid rgba(var(--ink-rgb), 0.35);
border-radius: 4px;
background: rgba(var(--ink-rgb), 0.06);
resize: vertical;
}
.live-bar {
margin-top: 0.5rem;
display: flex;
gap: 0.5rem;
align-items: center;
}
.live-run {
font: inherit;
font-size: 0.85rem;
padding: 0.25rem 0.9rem;
border-radius: 4px;
border: 1px solid rgba(var(--ink-rgb), 0.5);
background: rgba(var(--violet-rgb), 0.15);
cursor: pointer;
}
.live-run:hover { background: rgba(var(--violet-rgb), 0.3); }
.live-out {
margin: 0.5rem 0 0 0;
padding: 0.45rem 0.6rem;
min-height: 1.6rem;
font-size: 0.88rem;
white-space: pre-wrap;
border-left: 3px solid rgba(var(--violet-rgb), 0.6);
background: rgba(var(--ink-rgb), 0.06);
}
/* --- Front matter ------------------------------------------------- */
.title-page {
text-align: center;
margin: 3rem 0 2rem 0;
}
.title-page .title {
font-family: "Courier Prime", "Courier New", monospace;
font-size: 3.2rem;
letter-spacing: 0.22em;
margin: 0;
}
.title-page .subtitle {
font-family: "Courier Prime", "Courier New", monospace;
letter-spacing: 0.1em;
margin-top: 0.8rem;
opacity: 0.85;
}
h1.sidebar-title,
h2.sidebar-title {
position: absolute;
width: 1px;
height: 1px;
padding: 0;
margin: -1px;
overflow: hidden;
clip: rect(0, 0, 0, 0);
clip-path: inset(50%);
white-space: nowrap;
border: 0;
}
.personae {
max-width: 66ch;
}
.personae h3 {
font-variant: small-caps;
letter-spacing: 0.1em;
margin-top: 2rem;
border-bottom: 1px solid rgba(var(--ink-rgb), 0.35);
padding-bottom: 0.2rem;
}
.personae .who {
font-family: "Courier Prime", "Courier New", monospace;
font-weight: 700;
letter-spacing: 0.06em;
margin: 1rem 0 0.1rem 0;
}
.personae .what {
margin: 0 0 0.2rem 0;
font-style: italic;
opacity: 0.8;
}
.personae .desc {
margin: 0.15rem 0 0 0;
max-width: 60ch;
}
/* --- The reader's protagonist ------------------------------------ */
.pc-name {
font-weight: inherit;
border-bottom: 1px dotted rgba(var(--violet-rgb), 0.55);
}
.screenplay .slug,
.screenplay .transition,
.screenplay .character { text-transform: uppercase; }
.name-field {
border: 1px solid rgba(var(--violet-rgb), 0.55);
border-radius: 5px;
padding: 0.9rem 1rem;
margin: 1.6rem auto;
max-width: 60ch;
}
.name-label { margin: 0 0 0.6rem 0; }
.name-inputs { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.name-inputs input {
font: inherit;
padding: 0.3rem 0.6rem;
border: 1px solid rgba(var(--ink-rgb), 0.45);
border-radius: 4px;
background: rgba(var(--ink-rgb), 0.06);
max-width: 14ch;
}
.name-note {
font-size: 0.82rem;
opacity: 0.7;
margin: 0.6rem 0 0 0;
}
.name-label,
.name-confirm {
font-size: 1.2rem;
}
.name-inputs input,
.name-inputs button {
font: inherit;
font-size: 1.2rem;
}
/* --- Artifacts ---------------------------------------------------- */
.artifact {
font-family: ui-monospace, "Courier New", monospace;
font-size: 0.88rem;
line-height: 1.45;
max-width: 66ch;
margin: 1.4rem 0;
border-radius: 5px;
overflow: hidden;
}
.artifact p { margin: 0.1rem 0; }
/* Discord */
.discord { border: 1px solid rgba(var(--blurple-rgb), 0.5); }
.discord-head {
background: rgba(var(--blurple-rgb), 0.14);
padding: 0.4rem 0.8rem;
display: flex; gap: 0.8rem;
}
.discord-server { font-weight: 700; letter-spacing: 0.06em; }
.discord-channel { opacity: 0.75; }
.discord-body { padding: 0.7rem 0.8rem; }
.discord-msg { margin-bottom: 0.7rem; }
.discord-who { font-weight: 700; }
.discord-role {
font-size: 0.7rem; letter-spacing: 0.08em;
background: rgba(var(--violet-rgb), 0.25);
padding: 0.05rem 0.4rem; border-radius: 3px; margin-left: 0.4rem;
}
.discord-at { opacity: 0.55; margin-left: 0.5rem; font-size: 0.78rem; }
.discord-reacts { margin-top: 0.2rem !important; }
.react {
display: inline-block; font-size: 0.75rem;
border: 1px solid rgba(var(--ink-rgb),0.35); border-radius: 10px;
padding: 0 0.45rem; margin-right: 0.3rem;
}
/* Moderation log */
.modlog {
border-left: 3px solid var(--coral);
background: rgba(var(--coral-rgb), 0.08);
padding: 0.6rem 0.9rem;
font-size: 0.82rem;
letter-spacing: 0.03em;
}
/* Git */
.commit {
border: 1px solid rgba(var(--ink-rgb), 0.4);
padding: 0.7rem 0.9rem;
background: rgba(var(--ink-rgb), 0.05);
}
.commit-hash { color: var(--gold); font-weight: 700; }
.commit-meta { opacity: 0.7; }
.commit-msg { margin-top: 0.5rem; padding-left: 1.5rem; }
/* Terminal */
.terminal {
background: var(--panel-hard);
color: var(--ink);
padding: 0.7rem 0.9rem;
border: 1px solid rgba(var(--ink-rgb),0.35);
}
.term-in { color: var(--green); }
.term-in::before { content: ""; }
.term-out { opacity: 0.9; }
/* AI */
.aichat { border: 1px solid rgba(var(--green-rgb), 0.5); }
.ai-model {
background: rgba(var(--green-rgb), 0.16);
padding: 0.35rem 0.8rem !important;
font-weight: 700; letter-spacing: 0.1em; font-size: 0.75rem;
}
.ai-system { padding: 0.4rem 0.8rem; font-size: 0.8rem; opacity: 0.85; }
.ai-system pre { white-space: pre-wrap; margin: 0.4rem 0 0 0; }
.ai-body { padding: 0.6rem 0.8rem; }
.ai-turn { margin-bottom: 0.6rem; }
.ai-role { font-size: 0.68rem; letter-spacing: 0.12em; opacity: 0.6; }
.ai-assistant .ai-text { border-left: 2px solid rgba(46,160,120,0.6); padding-left: 0.6rem; }
/* Email */
.email { border: 1px solid rgba(var(--ink-rgb),0.45); padding: 0.7rem 0.9rem; }
.email-head td { padding: 0 0.6rem 0.1rem 0; vertical-align: top; font-size: 0.82rem; }
.email-head td:first-child { opacity: 0.6; }
.email-body { margin-top: 0.6rem; }
/* Handouts */
.handout {
border: 1px solid currentColor;
padding: 1rem 1.2rem;
font-family: "Courier Prime", "Courier New", monospace;
}
.handout-title {
font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase;
border-bottom: 1px solid currentColor; padding-bottom: 0.4rem;
margin-bottom: 0.7rem !important;
}
.handout-table { width: 100%; font-size: 0.85rem; margin: 0.5rem 0; }
.handout-table td.k { opacity: 0.65; width: 34%; padding-right: 1rem; vertical-align: top; }
/* --- Prose between scenes ---------------------------------------- */
.prose {
max-width: 64ch;
margin: 1.5rem 0 2rem 0;
font-family: "Iowan Old Style", "Palatino Linotype", Palatino,
"Book Antiqua", Georgia, serif;
font-size: 1.06rem;
line-height: 1.65;
color: var(--ink);
}
.prose p {
margin: 0 0 1.05rem 0;
}
.prose p:first-child { margin-top: 0; }
.prose p:last-child { margin-bottom: 0; }
blockquote.turn {
max-width: 64ch;
border-left: 3px solid rgba(var(--violet-rgb), 0.6);
padding-left: 1rem;
margin: 1.4rem 0 0.6rem 0;
}
.name-confirm {
margin: 0.7rem 0 0 0;
font-weight: 600;
}
/* --- The d20 ------------------------------------------------------ */
.roll {
border: 1px solid rgba(var(--violet-rgb), 0.5);
border-radius: 5px;
padding: 0.7rem 0.9rem;
margin: 1.2rem 0;
max-width: 60ch;
font-family: ui-monospace, "Courier New", monospace;
}
.roll-head {
display: flex;
justify-content: space-between;
font-size: 0.75rem;
letter-spacing: 0.12em;
opacity: 0.75;
margin-bottom: 0.5rem;
}
.roll-bar { display: flex; gap: 0.7rem; align-items: center; margin-top: 0.3rem; }
.roll-go, .roll-rewrite {
font: inherit;
font-size: 0.82rem;
padding: 0.25rem 0.9rem;
border-radius: 4px;
border: 1px solid rgba(var(--ink-rgb), 0.5);
background: rgba(var(--violet-rgb), 0.15);
cursor: pointer;
}
.roll-rewrite { background: rgba(var(--coral-rgb), 0.12); }
.roll-go:hover { background: rgba(var(--violet-rgb), 0.3); }
.roll-rewrite:hover { background: rgba(var(--coral-rgb), 0.25); }
.roll-value { font-size: 0.9rem; letter-spacing: 0.05em; }
.roll-out {
margin: 0.6rem 0 0 0 !important;
font-family: "Courier Prime", "Courier New", monospace;
min-height: 1.2rem;
}
.roll-echo { font-size: 0.8rem; opacity: 0.8; }
.roll-note { font-size: 0.8rem; opacity: 0.6; margin: 0.4rem 0 0 0 !important; }
.roll-foot {
font-size: 0.72rem;
letter-spacing: 0.1em;
opacity: 0.55;
margin: 0.5rem 0 0 0 !important;
border-top: 1px solid rgba(var(--ink-rgb),0.25);
padding-top: 0.35rem;
}
.roll-cue {
margin: 0.6rem 0 0 4ch !important;
font-family: "Courier Prime", "Courier New", monospace;
font-weight: 700;
letter-spacing: 0.06em;
}
.roll-line {
margin: 0 0 0 6ch !important;
max-width: 40ch;
font-family: "Courier Prime", "Courier New", monospace;
}
.roll-out .roll-line:first-child { margin-left: 0 !important; max-width: none; }
.companion-name {
font-family: "Courier Prime", "Courier New", monospace;
font-weight: 700;
letter-spacing: 0.14em;
font-size: 1.05rem;
margin: 0.7rem 0 0.3rem 0 !important;
}
.companion-intro { max-width: 58ch; margin: 0 0 0.3rem 0 !important; }
.session { max-width: 60ch; margin: 1.1rem 0; }
.session-who {
font-family: "Courier Prime", "Courier New", monospace;
font-weight: 700; letter-spacing: 0.12em; margin: 0 0 0.3rem 0 !important;
}
.session-text { margin: 0 !important; }
.ac-name { border-bottom: 1px dotted rgba(var(--violet-rgb), 0.55); }
.companion-naming { margin-top: 0.6rem; }
/* --- Plots -------------------------------------------------------- */
.plot {
border: 1px solid rgba(var(--violet-rgb), 0.5);
border-radius: 5px;
padding: 0.7rem 0.9rem;
margin: 1.2rem 0;
max-width: 62ch;
font-family: ui-monospace, "Courier New", monospace;
}
.plot-controls {
display: flex; gap: 1rem; flex-wrap: wrap;
font-size: 0.8rem; opacity: 0.85; margin: 0.4rem 0;
}
.plot-controls input {
font: inherit; font-size: 0.8rem; width: 7ch;
padding: 0.15rem 0.35rem;
border: 1px solid rgba(var(--ink-rgb),0.45);
border-radius: 3px;
background: rgba(var(--ink-rgb),0.06);
}
.plot-status { font-size: 0.75rem; letter-spacing: 0.1em; opacity: 0.7; }
.plot canvas {
display: block;
margin-top: 0.6rem;
background: var(--paper);
border: 1px solid rgba(var(--ink-rgb),0.3);
border-radius: 3px;
}
.roll-go:disabled, .roll-rewrite:disabled {
opacity: 0.4;
cursor: default;
}
.sketch {
border: 1px solid rgba(var(--violet-rgb), 0.5);
border-radius: 5px;
padding: 0.7rem 0.9rem;
margin: 1.2rem 0;
max-width: 62ch;
font-family: ui-monospace, "Courier New", monospace;
}
.sketch canvas {
display: block;
margin-top: 0.7rem;
background: var(--paper);
border: 1px solid rgba(var(--ink-rgb),0.3);
border-radius: 3px;
max-width: 100%;
}
.sketch-page {
margin-top: 0.7rem;
padding: 0.5rem 0.6rem;
border: 1px solid rgba(var(--ink-rgb),0.3);
border-radius: 3px;
background: rgba(var(--ink-rgb),0.04);
font-family: ui-monospace, "Courier New", monospace;
font-size: 0.9rem;
}
.sketch-page button {
font: inherit; font-size: 0.85rem;
border: 1px solid rgba(var(--ink-rgb),0.45);
border-radius: 3px;
background: rgba(var(--ink-rgb),0.08);
cursor: pointer;
min-width: 2ch;
}
/* --- The page itself, when Quarto is not doing it for us ---------- */
.screenplay, .artifact, .prose, .handout, .beats, .roll, .plot, .sketch,
.todo, .puzzle-box, .personae, .name-field, .live-cell, .session {
color: var(--ink);
}
.handout, .puzzle-cell, .sign { border-color: var(--rule); }
.terminal { background: var(--panel-hard); color: var(--ink); }
.title-page .title, .title-page .subtitle { color: var(--ink); }
/* --- Form controls -------------------------------------------------
Inputs, textareas and buttons do not inherit colour from the page,
so every one of them needs telling, or the reader types black on
black and cannot see what they are writing.
------------------------------------------------------------------- */
.name-inputs input,
.companion-input,
.todo-input,
.plot-controls input,
.live-src,
.sketch textarea,
.sketch-page input {
color: var(--ink);
background: var(--panel);
border-color: var(--rule);
caret-color: var(--ink);
}
.name-inputs input::placeholder,
.companion-input::placeholder,
.todo-input::placeholder,
.sketch-page input::placeholder,
.live-src::placeholder {
color: var(--ink-soft);
opacity: 1;
}
.roll-go, .roll-rewrite, .live-run, .todo-del,
.sketch-page button, .puzzle-cell {
color: var(--ink);
}
.sketch-page button {
background: var(--panel);
border-color: var(--rule);
}
/* Quarto's own search box does not follow the book's palette on every
theme, so it is told here as well. */
#quarto-search input,
#quarto-search .aa-Input,
.aa-Form,
.aa-InputWrapper input,
.quarto-search input {
background: var(--panel) !important;
color: var(--ink) !important;
border-color: var(--rule) !important;
}
.aa-Form { border: 1px solid var(--rule) !important; }
#quarto-search input::placeholder,
.aa-Input::placeholder {
color: var(--ink-soft) !important;
opacity: 1;
}
.aa-DetachedSearchButton, .quarto-search-button {
background: var(--panel) !important;
color: var(--ink) !important;
border-color: var(--rule) !important;
}
/* Canvases inherit nothing, so the sketch cells read their ink off the
element's own resolved colour. This is the line that gives them one. */
.sketch canvas, .plot canvas {
color: var(--ink);
background: transparent;
}
.tribute-heading {
margin: 2rem 0 0.5rem;
font-variant: small-caps;
font-weight: 600;
letter-spacing: 0.04em;
}
.tribute p {
margin: 0.6rem 0;
}
.tribute-meta {
margin-top: 2rem;
padding-top: 1rem;
border-top: 1px solid var(--bs-border-color);
text-align: right;
font-size: 0.85rem;
}
.tribute-meta p {
margin: 0.25rem 0;
}
.tribute-date {
font-style: italic;
}
.tribute-attribution {
font-size: 1rem;
}
.tribute-source {
margin-top: 0.75rem !important;
}
.footnote {
margin-top: 1.5rem;
font-size: 0.9rem;
color: var(--bs-secondary);
}
/* ---------------------------------------------------------------
The three endings.
All three are in the HTML. Which one is visible is a class on
<body>, written once by fedoras.reader/paint-standing! from the
reader's standing, so a chapter that forks does it here rather than
in nine lines of DOM work per passage.
A page with no class on it shows the middle one. That is what the
print edition gets, and it is what the table actually got, and the
PDF reads straight through with no gap and no note.
--------------------------------------------------------------- */
.ending { display: none; }
.ending-reconciled { display: block; }
body.standing-closed .ending-reconciled { display: none; }
body.standing-outstanding .ending-reconciled { display: none; }
body.standing-closed .ending-closed { display: block; }
body.standing-outstanding .ending-outstanding { display: block; }
@media print {
.ending { display: none !important; }
.ending-reconciled { display: block !important; }
}
/* ---------------------------------------------------------------
The slips.
--------------------------------------------------------------- */
.slip {
margin: 1.2rem 0 1.2rem 4ch !important;
padding-left: 1rem;
max-width: 46ch;
border-left: 2px solid rgba(var(--coral-rgb), 0.55);
font-family: "Courier Prime", "Courier New", monospace;
font-style: italic;
opacity: 0.8;
white-space: pre-wrap;
}
#quarto-margin-sidebar { display: none; }
.scene-code {
border: 1px solid var(--rule);
border-radius: 3px;
padding: 0.6rem 0.8rem;
margin: 0.9rem 0 1.1rem 0;
max-width: 62ch;
font-family: ui-monospace, "Courier New", monospace;
font-size: 0.88rem;
line-height: 1.45;
background: var(--panel);
color: var(--ink);
overflow-x: auto;
}
.scene-code pre { margin: 0; }
.scene-code code { background: none; padding: 0; }
/* Pressing Enroll flashes the name it confirms, the same name or a new
one, so the press can be seen to have done something. */
.name-confirm .pc-name.pc-flash {
animation: pc-flash 1.4s ease-out;
}
@keyframes pc-flash {
0%, 30% { color: var(--green); }
}</style><script src="scittle.js" type="application/javascript"></script><div style="display:none;"><script type="application/x-scittle">(ns fedoras.carry
"What the reader carries between chapters."
(:require [clojure.string :as str]))
(def ^:private book-key
"The registration on the front of the file. It is not a secret and it
is not pretending to be one — it is the number this is keyed to, and
it is the same number a reader has been looking at since August."
3812)
;; ---------------------------------------------------------------------
;; Bytes
;; ---------------------------------------------------------------------
(defn- to-bytes [s] (.encode (js/TextEncoder.) s))
(defn- from-bytes [b] (.decode (js/TextDecoder. "utf-8") b))
(defn- bytes->str [b]
(loop [i 0 acc ""]
(if (>= i (.-length b))
acc
(recur (inc i) (str acc (js/String.fromCharCode (aget b i)))))))
(defn- str->bytes [s]
(let [out (js/Uint8Array. (count s))]
(dotimes [i (count s)] (aset out i (.charCodeAt s i)))
out))
;; ---------------------------------------------------------------------
;; The keystream
;;
;; The same small xorshift the dice and the floors use, so there is one
;; generator in this project and not four.
;; ---------------------------------------------------------------------
(defn- keystream [n seed]
(let [out (js/Uint8Array. n)]
(loop [i 0 x (bit-or 1 (bit-and seed 0x7fffffff))]
(if (>= i n)
out
(let [x (bit-and (bit-xor x (bit-shift-left x 13)) 0x7fffffff)
x (bit-and (bit-xor x (unsigned-bit-shift-right x 17)) 0x7fffffff)
x (bit-and (bit-xor x (bit-shift-left x 5)) 0x7fffffff)]
(aset out i (bit-and x 0xff))
(recur (inc i) x))))))
(defn- mask [b seed]
(let [k (keystream (.-length b) seed)
out (js/Uint8Array. (.-length b))]
(dotimes [i (.-length b)] (aset out i (bit-xor (aget b i) (aget k i))))
out))
;; ---------------------------------------------------------------------
;; Base64, url-safe
;; ---------------------------------------------------------------------
(defn- b64 [b]
(-> (js/btoa (bytes->str b))
(str/replace "+" "-")
(str/replace "/" "_")
(str/replace "=" "")))
(defn- un-b64 [s]
(let [t (-> s (str/replace "-" "+") (str/replace "_" "/"))
pad (case (mod (count t) 4) 2 "==" 3 "=" "")]
(str->bytes (js/atob (str t pad)))))
;; ---------------------------------------------------------------------
;; Rolls, short
;; ---------------------------------------------------------------------
(defn- pack-rolls
"[roll mod rewrites], shortest form. A roll with no modifier and no
rewrites is one number."
[rolls]
(into {}
(for [[id {:keys [roll mod rewrites]}] rolls
:when roll]
[id (cond
(pos? (or rewrites 0)) [roll (or mod 0) rewrites]
(not (zero? (or mod 0))) [roll mod]
:else [roll])])))
(defn- unpack-rolls
"Every shape this has ever emitted: a bare number, the short vector,
and the verbose map that went out while `pack-rolls` was sitting here
unused. Tokens from before this change still read."
[m]
(into {}
(for [[id v] m]
[(clojure.core/name id)
(cond
(number? v) {:roll v :mod 0 :rewrites 0}
(map? v) {:roll (:roll v)
:mod (or (:mod v) 0)
:rewrites (or (:rewrites v) 0)}
:else {:roll (nth v 0)
:mod (nth v 1 0)
:rewrites (nth v 2 0)})])))
;; ---------------------------------------------------------------------
;; The token
;; ---------------------------------------------------------------------
(defn- checksum [b]
(loop [i 0 s 7]
(if (>= i (.-length b))
(mod s 251)
(recur (inc i) (mod (+ (* s 31) (aget b i)) 251)))))
(defn pack
"A map to a token. The keys are one letter each because this goes in
a query string thirty times a page."
[{:keys [name companion echo rolls deeds epoch todo]}]
(try
(let [payload (js/JSON.stringify
(clj->js
(cond-> {}
name (assoc :n name)
companion (assoc :a [(:n companion) (:given companion)])
(pos? (or echo 0)) (assoc :e echo)
(seq rolls) (assoc :r (pack-rolls rolls))
(seq deeds) (assoc :d (mapv clojure.core/name deeds))
;; when the reader last withdrew the whole record.
;; it travels because the alternative is that only
;; the state travels, and then a link from before
;; the withdrawal quietly reinstates it.
(pos? (or epoch 0)) (assoc :g epoch)
(seq todo) (assoc :t [(:seq todo 0) (:items todo)]))))
body (mask (to-bytes payload) book-key)
out (js/Uint8Array. (inc (.-length body)))]
(aset out 0 (checksum body))
(dotimes [i (.-length body)] (aset out (inc i) (aget body i)))
(b64 out))
(catch :default _ nil)))
(defn unpack
"A token back to a map, or nil if anybody has been at it.
An absent field comes back empty rather than missing, which is fine
and is not a licence: the caller merges this forward and knows that an
empty Echo means the token is old, not that the Echo is nought."
[s]
(try
(when-not (str/blank? s)
(let [raw (un-b64 s)
want (aget raw 0)
body (.slice raw 1)]
(when (= want (checksum body))
(let [m (js->clj (js/JSON.parse (from-bytes (mask body book-key)))
:keywordize-keys true)]
{:name (:n m)
:companion (when-let [a (:a m)] {:n (first a) :given (or (second a) "")})
:echo (or (:e m) 0)
:rolls (unpack-rolls (or (:r m) {}))
:deeds (mapv keyword (or (:d m) []))
:epoch (or (:g m) 0)
:todo (when-let [t (:t m)] {:seq (first t) :items (or (second t) [])})}))))
(catch :default _ nil)))
;; ---------------------------------------------------------------------
;; When it does not reconcile
;; ---------------------------------------------------------------------
(defn complain! []
(js/console.warn
"016.09 — entry does not reconcile and has not been carried forward. Retained."))</script><script type="application/x-scittle">(ns fedoras.reader
"Everything the reader owns.
One atom: containing Name, animal, echo, fortune, score, deeds. A widget
reads it and never touches storage directly, and every change goes through
one of the setters, which writes, re-reads, and lets the watches fire."
(:require [clojure.string :as str]
[fedoras.carry :as carry]))
;; ---------------------------------------------------------------------
;; Storage
;; ---------------------------------------------------------------------
(def prefix "fedoras.")
(def carry-param :f)
(def forget-param
"A page that loads with this on it withdraws its own record and stops.
It is a separate field from the token because it must work on a page
that has never seen a token."
:forget)
(def withdrawn-param
"Survives exactly one reload, to say the thing was done. The state it
would otherwise have been recorded in has just been deleted, which is
the one place a confirmation cannot live."
:withdrawn)
(def legacy-params
"The fields the query string used to carry, one per fact. Stripped off
any link that still has them. There was a second copy of this list
called `carried-params` and the two had drifted."
[:pc :pcl :ac :acn :echo :fortune :score])
(defn- read-json [s]
(js->clj (js/JSON.parse s) :keywordize-keys true))
(defn- write-json [v]
(js/JSON.stringify (clj->js v)))
(defn stored [key]
(try
(when-let [s (.getItem js/localStorage (str prefix (name key)))]
(read-json s))
(catch :default _ nil)))
(defn store! [key val]
(try (.setItem js/localStorage (str prefix (name key)) (write-json val))
(catch :default _ nil))
val)
(defn remove!
"Take something out rather than writing an empty one over it, because
a stored nil and a missing key read back the same and only one of them
is what was meant."
[key]
(try (.removeItem js/localStorage (str prefix (clojure.core/name key)))
(catch :default _ nil)))
(defn storage-works?
"Whether anything at all is going to be persisted.
On a file:// path some browsers give every page its own opaque origin,
which means localStorage throws and the whole book forgets the reader
the moment they click anything. Worth knowing rather than guessing."
[]
(try
(.setItem js/localStorage (str prefix "probe") "1")
(let [ok (= "1" (.getItem js/localStorage (str prefix "probe")))]
(.removeItem js/localStorage (str prefix "probe"))
ok)
(catch :default _ false)))
;; ---------------------------------------------------------------------
;; The query string, which is a transport and nothing else
;; ---------------------------------------------------------------------
(defn- current-url [] (js/URL. (.-href js/location)))
(defn param [key]
(try
(let [v (.get (.-searchParams (current-url)) (name key))]
(when-not (str/blank? v) v))
(catch :default _ nil)))
(defn set-params! [m]
(try
(let [u (current-url) sp (.-searchParams u)]
(doseq [[k v] m]
(if (or (nil? v) (= "" v))
(.delete sp (name k))
(.set sp (name k) (str v))))
(.replaceState js/history nil "" (.toString u)))
(catch :default _ nil)))
(defn- int-or [v d]
(let [n (js/parseInt (str v) 10)] (if (js/isNaN n) d n)))
;; ---------------------------------------------------------------------
;; The atom
;; ---------------------------------------------------------------------
(def default-name ["Owen" "Mercer"])
(def state (atom nil))
(def animal-names
"Number to the animal's grammar: what it is called, what more than one
of them is called, what a ledger would file it under. Filled in by
`fedoras.state/assets` from a later script tag, so it is empty for the
moment between this file being read and the roster arriving, and
nothing here may treat an empty roster as a missing roll."
(atom {}))
(defn- as-grammar
"One roster entry, whatever shape it turned up in.
The page used to be handed {1 \"Pigeon\"} and is now handed
{1 {:animal \"Pigeon\" :plural \"pigeons\" ...}}, and a book whose
`names-form` has not caught up with its roster hands over one of each.
A bare string is an animal with no grammar, which is precisely what it
was before, so it becomes one here.
This is normalised at the boundary rather than at each use because the
alternative was a `merge` three functions away receiving a string,
throwing `conj on a map takes map entries`, and taking down every
render watch on the page — a build that is one function out of step
should read a little worse, not stop."
[v]
(cond
(map? v) v
(string? v) {:animal v}
:else {}))
(defn- read-companion []
(let [s (stored :companion)
n (int-or (first s) nil)]
(when (and n (<= 1 n 20))
(let [given (or (nth s 2 nil) "")
g (as-grammar (get @animal-names n))
;; the animal's name is a convenience and the roster may not
;; have landed yet. the number is the fact.
animal (or (:animal g) (nth s 1 nil) "")
named? (not (str/blank? given))]
(merge {:plural "" :taxonomy "" :collective "" :other-names []}
g
{:n n
:animal animal
:given given
:named? named?
:name (cond named? (str/trim given)
(not (str/blank? animal)) animal
:else (str "d20 " n))})))))
(defn- read-name []
(let [s (stored :pc)]
[(or (first s) (first default-name))
(or (second s) (second default-name))]))
(defn refresh!
"Total on purpose. Every render watch in the book hangs off this atom,
so anything that throws in here blanks the whole page, and what it
reads is JSON that a previous version of this file wrote, which is not
a thing to be optimistic about. A key that is the wrong shape reads as
absent."
[]
(reset! state
{:name (read-name)
:companion (try (read-companion) (catch :default _ nil))
:echo (int-or (stored :echo) 0)
:rolls (let [r (stored :rolls)] (if (map? r) r {}))
:deeds (let [d (stored :deeds)]
(set (map keyword (if (sequential? d) d []))))
:epoch (int-or (stored :epoch) 0)
:todo (let [t (stored :todo)] (if (sequential? t) t []))
:todo-seq (int-or (stored :todo-seq) 0)}))
;; ---------------------------------------------------------------------
;; What a chapter may ask for
;; ---------------------------------------------------------------------
(defn reader-name [] (:name @state))
(defn companion [] (:companion @state))
(defn echo [] (:echo @state))
(defn deeds [] (:deeds @state))
(defn fortune [] (count (:deeds @state)))
(defn epoch
"When this reader last withdrew the whole record, in seconds, or
nought if they never have.
It is not a clock and nothing displays it. It exists so that a
withdrawal can be compared against a link: a token stamped earlier
than this was written by somebody who has since been forgotten, and it
is not allowed to put them back."
[]
(:epoch @state))
(defn standing
"Fortune less echo. Added to every roll for the rest of the book, and
the number the last chapter reads to decide how it ends."
[]
(- (fortune) (echo)))
(defn registration [] "3812")
;; ---------------------------------------------------------------------
;; And what it may change
;; ---------------------------------------------------------------------
(defn set-name! [f l]
(store! :pc [(if (str/blank? f) (first default-name) (str/trim f))
(if (str/blank? l) (second default-name) (str/trim l))])
(refresh!))
(defn set-companion!
"Three cells: the number, the animal's own name as a courtesy, and
whatever the reader called it. The number is the only one that has to
be right, because the other two are recovered from the roster."
[n given]
(store! :companion [n (get-in @animal-names [n :animal] "") (or given "")])
(refresh!))
(defn set-echo! [n] (store! :echo (max 0 n)) (refresh!))
(defn add-echo!
"One more thing taken back."
[]
(set-echo! (inc (echo))))
(defn did!
"Record a deed. A set, so doing the same thing twice is doing it once,
and nothing anywhere says that it happened."
[k]
(store! :deeds (mapv name (conj (deeds) (keyword k))))
(refresh!))
(defn animals!
"The roster's grammar, from the page. Normalised on the way in, so the
shape `fedoras.state/names-form` happens to be emitting this week is
something only this function has an opinion about.
Refreshes, because a companion read before this arrived is holding an
empty animal name."
[m]
(reset! animal-names
(if (map? m)
(into {} (map (fn [[k v]] [k (as-grammar v)])) m)
{}))
(refresh!))
(defn rolls
"Every check the reader has resolved, by id.
Normalised on the way out. Storage keywordizes keys on read, and a
check id is an arbitrary string rather than a name, so the keys come
back as keywords and nothing matches them. And anything that is not a
map at all becomes an empty one, because assoc on a vector with a
string key takes the page down."
[]
(let [r (:rolls @state)]
(if (map? r)
(into {} (map (fn [[k v]] [(name k) v])) r)
{})))
(defn roll-entry [id]
(when-let [e (get (rolls) id)]
{:roll (or (:roll e) (get e "roll"))
:mod (or (:mod e) (get e "mod") 0)
:rewrites (or (:rewrites e) (get e "rewrites") 0)}))
(defn remember-roll! [id e]
(store! :rolls (assoc (rolls) id e))
(refresh!))
(defn score []
(+ (reduce + 0 (keep :roll (vals (rolls))))
(or (:n (companion)) 0)))
;; ---------------------------------------------------------------------
;; Import, once, on arrival
;; ---------------------------------------------------------------------
(def carries-epoch?
"Whether the codec on this page round-trips a withdrawal stamp."
(try
(= 12345 (:epoch (carry/unpack
(carry/pack {:name ["Owen" "Mercer"] :epoch 12345}))))
(catch :default _ false)))
(defn- wipe!
"Everything under the prefix, and then one thing: when that happened."
[at]
(try
(let [ks (vec (for [i (range (.-length js/localStorage))
:let [k (.key js/localStorage i)]
:when (and k (str/starts-with? k prefix))]
k))]
(doseq [k ks] (.removeItem js/localStorage k)))
(catch :default _ nil))
(store! :epoch at))
(defn- merge-token!
[{:keys [name companion echo rolls deeds epoch todo]}]
(let [ours (int-or (stored :epoch) 0)
theirs (or epoch 0)]
(cond
;; A link from before the reader withdrew the record. It is a true
;; account of somebody who does not exist any more, which is not
;; the same thing as an instruction to rebuild them. This is the
;; case that made `forget!` a lie: it emptied one page's storage
;; and every other page, and every entry in the back history, was
;; still holding a complete copy and handed it straight back.
;; A link from before the reader withdrew the record. It is a true
;; account of somebody who does not exist any more, which is not
;; the same thing as an instruction to rebuild them.
;;
;; Only when the codec can say so. A page that cannot read a stamp
;; off a token must not conclude from its absence that every link
;; in the book is stale.
(and carries-epoch? (< theirs ours))
(js/console.info
(str "016.09 — the link this page was opened from was written before the record "
"was withdrawn. Nothing carried forward. Reach this chapter from a page you "
"have opened since, and whatever is current will arrive with you."))
:else
(do
;; They withdrew it somewhere this page has not heard about yet.
;; The erasure travels the way the state travels, which is the
;; only way anything travels in a book read off a disk.
(when (and carries-epoch? (> theirs ours))
(wipe! theirs)
(js/console.info
"016.09 — prior record withdrawn at the reader's request. Nothing carried forward."))
;; the name is the one thing a reader can retype in five seconds,
;; so the token is allowed to have an opinion about it
(when (seq name)
(store! :pc name))
;; The animal:
;;
;; This was write-once — take the token's only if there is
;; nothing here — which is right on one origin and wrong on a
;; folder of files, where every page has its own storage and the
;; token is the only thing that crosses. A reader who opened Act
;; II after rolling and before naming taught that page the horse,
;; permanently, and Act II could never afterwards learn that the
;; horse was called Horace.
;;
;; The Echo is the recency stamp. It only ever goes up, and a
;; reroll raises it, so a token carrying an Echo at least as
;; large as this page's is at least as new as this page and is
;; allowed to speak. One older, and it is a link from before the
;; reroll and is not.
(let [have (read-companion)
here-echo (int-or (stored :echo) 0)
there-echo (or echo 0)]
(when (and (:n companion)
(or (nil? have) (>= there-echo here-echo)))
(store! :companion
[(:n companion) ""
;; a blank name in a token is a reader who had not
;; named it yet, not a reader who unnamed it
(if (str/blank? (:given companion))
(or (:given have) "")
(:given companion))])))
;; upward only, always. after the companion, which reads it.
(store! :echo (max (int-or (stored :echo) 0) (or echo 0)))
;; a check is resolved once, and what is already in this browser
;; was rolled by this reader, so it wins every collision
(when (seq rolls)
(let [named (fn [m] (if (map? m)
(into {} (map (fn [[k v]] [(clojure.core/name k) v])) m)
{}))]
(store! :rolls (merge (named rolls) (named (stored :rolls))))))
;; deeds are a set, and a set does not get smaller by being described
(when (seq deeds)
(let [held (let [d (stored :deeds)] (if (sequential? d) d []))]
(store! :deeds (vec (into (set (map clojure.core/name held))
(map clojure.core/name deeds))))))
(when-let [t todo]
(when (>= (:seq t 0) (int-or (stored :todo-seq) 0))
(store! :todo (:items t))
(store! :todo-seq (:seq t))))))))
(defn- import-token! []
(if-let [t (param carry-param)]
(if-let [m (try (fedoras.carry/unpack t) (catch :default _ nil))]
(merge-token! m)
(try (fedoras.carry/complain!) (catch :default _ nil)))
;; nothing to do, unless somebody has a link from before the token
(do
(when-let [pc (param :pc)]
(store! :pc [pc (or (param :pcl) (second default-name))]))
(when-let [ac (param :ac)]
(let [n (int-or ac nil)]
(when (and n (<= 1 n 20) (nil? (read-companion)))
(store! :companion [n "" (or (param :acn) "")]))))
(when-let [e (param :echo)]
(store! :echo (max (int-or (stored :echo) 0) (int-or e 0)))))))
(defn- withdraw-if-asked!
"A page loaded with a withdrawal stamp on it clears itself and does
nothing else.
This is how one button reaches twelve documents that cannot see each
other. The page the reader clicked opens each of the others in a
hidden frame with the stamp in the query string, and each one runs
this on the way up. Nothing is scripted across the boundary — every
file is its own origin and none of them can touch another's storage —
but a document can always clear its own, and a query string is the one
thing that crosses.
Returns true if this load was a withdrawal, so boot knows to skip the
rest of its work."
[]
(when-let [at (some-> (param forget-param) (int-or nil))]
(when (> at (int-or (stored :epoch) 0))
(wipe! at))
true))
;; ---------------------------------------------------------------------
;; Rendering
;; ---------------------------------------------------------------------
(defn on-render! [k f] (add-watch state k (fn [_ _ _ _] (f))) (f))
(defn el [id] (.getElementById js/document id))
(defn q [node selector] (when node (.querySelector node selector)))
(defn q-all
"Every match, as a vector. One argument searches the document; two
searches inside a node.
Written the long way because a NodeList is not a Clojure collection
and array-seq is not in Scittle's bindings."
([selector] (q-all js/document selector))
([node selector]
(if-not node
[]
(let [nodes (.querySelectorAll node selector)]
(mapv (fn [i] (.item nodes i)) (range (.-length nodes)))))))
(defn text! [node selector s]
(when-let [t (q node selector)] (set! (.-textContent t) s)))
(defn on-click! [node selector f]
(when-let [b (q node selector)] (set! (.-onclick b) f)))
(defn enable! [node selector on? label]
(when-let [b (q node selector)]
(set! (.-disabled b) (not on?))
(when label (set! (.-textContent b) label))))
(defn show! [node selector on?]
(when-let [t (q node selector)]
(set! (.-display (.-style t)) (if on? "flex" "none"))))
(defn widget [k id f]
(on-render! k (fn [] (when-let [node (el id)] (f node)))))
;; ---------------------------------------------------------------------
;; Withdrawing the record, everywhere
;;
;; Twelve documents, each its own origin, none able to read another's
;; storage. Every shared channel is shut: localStorage and IndexedDB are
;; origin-scoped, window.name is cleared on the way across, cookies do
;; not apply to a file, and an iframe gets its own origin so the parent
;; cannot script it.
;;
;; It can still LOAD it. A hidden frame pointed at a sibling chapter,
;; with a stamp in the query string, runs that chapter's own copy of
;; this file, which clears that chapter's own storage. Nothing crosses
;; the boundary except the URL, which is the one thing that was ever
;; going to.
;; ---------------------------------------------------------------------
(defn- sibling-pages
"Every other chapter this page links to.
Read off the sidebar rather than configured, because Quarto already
puts the whole book in it and a hand-kept list of filenames is a list
that goes stale the first time a chapter is renamed."
[]
(let [here (.-pathname js/location)
dir (subs here 0 (inc (.lastIndexOf here "/")))]
(->> (q-all "a[href]")
(keep (fn [a]
(let [h (.getAttribute a "href")]
(when (and h
(not (str/starts-with? h "#"))
(not (re-find #"(?i)^(https?:|mailto:|javascript:)" h)))
(try
(let [u (js/URL. (.-href a))
p (.-pathname u)]
(when (and (str/starts-with? p dir)
(str/ends-with? (str/lower-case p) ".html")
(not= p here))
(str (.-protocol u) "//" (.-host u) p)))
(catch :default _ nil))))))
distinct
vec)))
(defn- sweep!
"Tell every other chapter to withdraw, then call `done` once.
Once, whatever happens: a frame that never fires must not leave the
reader looking at a button that has stopped meaning anything, so there
is a deadline as well as a count."
[at done]
(let [pages (sibling-pages)
fired (atom false)
finish (fn [] (when-not @fired (reset! fired true) (done)))]
(if (empty? pages)
(finish)
(let [box (.createElement js/document "div")
left (atom (count pages))
one (fn [] (when (zero? (swap! left dec)) (finish)))]
(js/console.info "016.09 — withdrawing from" (count pages) "other chapters")
(set! (.-style box)
"position:absolute;width:0;height:0;overflow:hidden;border:0;visibility:hidden")
(.appendChild (.-body js/document) box)
(doseq [p pages]
(let [f (.createElement js/document "iframe")]
(set! (.-onload f) (fn [_] (one)))
(set! (.-onerror f) (fn [_] (one)))
(set! (.-src f) (str p "?" (clojure.core/name forget-param) "=" at))
(.appendChild box f)))
(js/setTimeout finish 5000)))))
(defn forget!
"Forget everything, not the six things somebody remembered to list,
and not only on this page.
Emptying this document's storage was never the whole job: the reader
was also sitting, complete, in the query string of every link on every
other chapter and in every entry of the back history, and the next
navigation put them back. So this clears here, stamps when, and then
visits every other chapter to say so. The stamp is what makes a link
written before the withdrawal refuse to be believed afterwards.
It also says so while it is happening. It used to do all of this in
silence and then reload, which is indistinguishable from a button that
does nothing except reload."
[]
(let [at (quot (.now js/Date) 1000)
btn (q js/document ".pc-forget")]
(when btn
(set! (.-disabled btn) true)
(set! (.-textContent btn) "Withdrawing the record…"))
(wipe! at)
(sweep! at
(fn []
(let [u (current-url)]
(doseq [k (concat [carry-param forget-param] legacy-params)]
(.delete (.-searchParams u) (clojure.core/name k)))
(.set (.-searchParams u) (clojure.core/name withdrawn-param) "1")
(set! (.-href js/location) (.toString u)))))))
(defn- note-withdrawal!
"One line, on the way back up, and then the button goes back to
offering. The confirmation cannot be stored, because storing things is
what has just been undone — so it is read off the query string once,
before anything else in boot is allowed to tidy the query string away."
[withdrew?]
(when withdrew?
(js/console.info
"016.09 — record withdrawn from this chapter and from every chapter linked from it.")
(when-let [b (q js/document ".pc-forget")]
(set! (.-textContent b) "Record withdrawn")
(js/setTimeout (fn [] (set! (.-textContent b) "Forget everything")) 5000))))
;; ---------------------------------------------------------------------
;; Export
;; ---------------------------------------------------------------------
(defn token
"What this reader looks like from outside. Recomputed rather than
stored, so it cannot disagree with the state it is describing.
Guarded, because this runs on every render and inside `decorate-links!`,
and a codec that throws on one unexpected key should cost the reader a
shareable link and nothing else."
[]
(try
(let [{:keys [name companion echo rolls deeds todo todo-seq]} @state]
(fedoras.carry/pack
{:name name
:companion (when companion (select-keys companion [:n :given]))
:echo echo
:rolls rolls
:deeds deeds
:epoch (epoch)
:todo (when (seq todo) {:seq (or todo-seq 0) :items todo})}))
(catch :default e
(js/console.warn "fedoras: could not pack the carry token —" e)
nil)))
(defn decorate-links!
"Every internal link carries one field.
Two things were wrong before this and both of them mattered. It ran
inline, at parse time, so any link below the script tag did not exist
yet — which is every prev-and-next arrow Quarto puts in the footer.
And it copied the query string rather than the state, so a page opened
from storage handed on nothing."
[]
(when-let [t (token)]
(doseq [a (q-all "a[href]")]
(let [h (.getAttribute a "href")]
(when (and h
(not (str/starts-with? h "#"))
(not (re-find #"(?i)^(https?:|mailto:|javascript:)" h)))
(try
(let [lu (js/URL. (.-href a))
sp (.-searchParams lu)]
(doseq [k legacy-params] (.delete sp (clojure.core/name k)))
(.set sp (clojure.core/name carry-param) t)
(set! (.-href a) (.toString lu)))
(catch :default _ nil)))))))
(defn- rewrite-address!
"Put the token in this page's own address bar and take the old fields
off it, so a reader who arrived on a legacy link stops looking at
their own Echo."
[]
(when-let [t (token)]
(set-params! (into {(clojure.core/name carry-param) t}
(map (fn [k] [k nil])
(concat [forget-param withdrawn-param] legacy-params))))))
;; ---------------------------------------------------------------------
;; Tokens
;;
;; It used to be a chain of str/replace calls, which is why {pc-last}
;; worked in a scene and rendered as the literal characters {pc-last}
;; inside a dice passage.
;;
;; Case follows the token: {ac} is `ted`, {Ac} is `Ted`, {AC} is `TED`,
;; so a passage can start a sentence or write a cue line without the
;; author reaching for a second token. Note that this makes {PC} in an
;; already-written scene render as OWEN rather than Owen; the old regex
;; was case-insensitive and threw the information away.
;;
;; An unkown token is passed over: A brace in a passage that is not
;; something this understands comes out exactly as it went in, so this
;; is safe to run over arbitrary prose.
;; ---------------------------------------------------------------------
(def ^:private token-re #"\{([A-Za-z]+)(-[A-Za-z-]+)?\}")
(defn- apply-case [head s]
(cond
(str/blank? s) s
(= head (str/upper-case head)) (str/upper-case s)
(= (subs head 0 1) (str/upper-case (subs head 0 1)))
(str (str/upper-case (subs s 0 1)) (subs s 1))
:else s))
(defn render
"Replace every {token} the resolver knows. `resolve` is called with the
lower-cased head and the lower-cased tail — \"ac\" and \"-plural\" for
{ac-plural} — and returns a string or nil."
[resolve s]
(str/replace (or s "") token-re
(fn [m]
(let [[whole head tail] (if (string? m) [m m nil] m)]
(or (some->> (resolve (str/lower-case head)
(some-> tail str/lower-case))
(apply-case head))
whole)))))
(defn- string-hash
"Stable across loads, which is the point: the same sentence picks the
same alternative name every time the reader opens the page, so nothing
reads as though it were rolled twice."
[s]
(reduce (fn [a i] (mod (+ (* 31 a) (.charCodeAt s i)) 1000003))
7 (range (count s))))
(defn- an [s]
(str (if (re-find #"(?i)^[aeiou]" (str s)) "an " "a ") s))
(defn- animal-tokens
"What a passage may say about the animal. The reader's own name for it
is a name; everything else is the species, because a reader who called
a marmot Ted did not thereby decide that two of them are Teds."
[source tail]
(when-let [{:keys [animal plural taxonomy collective other-names name named?]}
(companion)]
(let [kind (str/lower-case (or animal ""))]
(case (or tail "-name")
"-name" (if named? name (str "the " kind))
"-kind" kind
"-a" (an kind)
"-plural" (if (str/blank? plural) (str kind "s") (str/lower-case plural))
"-many" (if (str/blank? collective)
(str "several " (if (str/blank? plural) (str kind "s") plural))
(str (an collective) " of "
(if (str/blank? plural) (str kind "s") plural)))
"-taxonomy" (str/lower-case (or taxonomy kind))
"-given" (if named? name "")
"-other" (if (seq other-names)
(nth other-names (mod (string-hash source) (count other-names)))
(str "the " kind))
nil))))
(defn- reader-tokens [source]
(let [[f l] (reader-name)]
(fn [head tail]
(case head
"pc" (case (or tail "-first")
"-first" f
"-full" (str f " " l)
"-last" l
nil)
"ac" (or (animal-tokens source tail)
;; no roll yet, and a passage still has to read
(case (or tail "-name")
("-name" "-kind" "-other") "the animal"
"-a" "an animal"
"-plural" "animals"
"-many" "several animals"
"-taxonomy" "animal"
"-given" ""
nil))
nil))))
(defn fill-with
"Put the reader into a passage, plus whatever else the caller knows.
The dice box passes the die in this way."
[extra s]
(let [own (reader-tokens s)]
(render (fn [h t] (or (extra h t) (own h t))) s)))
(defn fill
"Put the reader into a passage. The only place any of these are
resolved."
[s]
(fill-with (fn [_ _] nil) s))
(defn animal-label
"Kept for anything still asking. The display name, as stored, not
shouted — the old one upper-cased and every caller lower-cased it
again somewhere else."
[]
(when-let [c (companion)] (:name c)))
;; ---------------------------------------------------------------------
;; The carry-over
;;
;; What a reader takes to the next book.
;; ---------------------------------------------------------------------
(def on-the-record
"What goes in the token. Everything else is furniture.
A key is on this list because it is small and because losing it would
lose the reader's year. Adding one is a decision about how long every
link on every page is going to be, so it is a list and not a
convention."
#{:pc :companion :echo :rolls :deeds :todo})
(defn kept
"Read something the reader left in a room. No widget that calls this
needs to know anything about tokens."
[k]
(stored k))
(defn keep!
"Leave something in a room. It stays where it was made."
[k v]
(store! k v)
(when (contains? on-the-record k) (refresh!))
v)
(def ^:private alphabet "23456789ABCDEFGHJKLMNPQRSTUVWXYZ")
(defn- b32 [n len]
(loop [n n i 0 out ""]
(if (= i len)
out
(recur (quot n 32) (inc i)
(str (nth alphabet (mod n 32)) out)))))
;; ---------------------------------------------------------------------
;; The name and the animal, on every page
;; ---------------------------------------------------------------------
(defn- paint-name []
(let [[f l] (reader-name)]
(doseq [node (q-all ".pc-name")]
(set! (.-textContent node)
(apply-case (or (.getAttribute node "data-case") "pc")
(case (.getAttribute node "data-pc")
"-full" (str f " " l) "-last" l f))))
(when-let [i (el "pc-first")] (when (str/blank? (.-value i)) (set! (.-value i) f)))
(when-let [i (el "pc-last")] (when (str/blank? (.-value i)) (set! (.-value i) l)))))
(defn- paint-companion
"Each span carries the token that made it, so {ac-plural} written in a
scene at build time still says `marmots` after the reader rolls a
marmot. It used to carry nothing and every span got the same word."
[]
(doseq [node (q-all ".ac-name")]
(let [tail (or (.getAttribute node "data-ac") "-name")
head (or (.getAttribute node "data-case") "ac")]
(set! (.-textContent node)
(or (some->> ((reader-tokens (or (.-textContent node) "")) "ac" tail)
(apply-case head))
"the animal")))))
(defn- paint-tokens []
(doseq [node (q-all ".tok")]
(set! (.-textContent node) (fill (.getAttribute node "data-tok")))))
;; ---------------------------------------------------------------------
;; Ending / Standing
;; ---------------------------------------------------------------------
(def deed-roll
[:nerve ;; a natural twenty with the Echo at nought
:named-it ;; the animal was given a name and kept it
:kept-the-programmes ;; both sheets went in the bag and stayed there
:no-name-for-the-box ;; nothing was spoken into the undertaker's box
:read-it-back ;; the ledger was read against the room out loud
:opened-the-cage
:held-the-door
:went-back-for-it
:signed-nothing
:walked-out
:told-a-new-one ;; Ariathne was paid in something that was theirs
:said-why]) ;; the chancellor asked, and got a true answer
(def ^:private deed-bits 15)
(defn- deed-mask []
(let [held (deeds)]
(reduce (fn [acc [index deed]]
(if (contains? held deed)
(+ acc (bit-shift-left 1 index))
acc))
0
(map-indexed vector deed-roll))))
(defn- deeds-from-mask [mask]
(set (keep-indexed (fn [index deed]
(when (pos? (bit-and mask (bit-shift-left 1 index)))
deed))
deed-roll)))
(def band-code {:closed 0 :reconciled 1 :outstanding 2})
(def code-band {0 :closed 1 :reconciled 2 :outstanding})
(defn ending-band []
(let [reader-standing (standing)]
(cond
(>= reader-standing 4) :outstanding
(>= reader-standing 0) :reconciled
:else :closed)))
(defn- paint-standing!
"One class on the body, so a chapter that forks three ways does it in
the stylesheet instead of in nine lines of DOM work per passage. A page
with no class on it shows :reconciled, which is what the print edition
gets and what the table actually got.
This existed and was never wired to anything, which meant every
`sp/by-standing` on every page was rendering all three endings at
once, or none."
[]
(when-let [body (.-body js/document)]
(let [classes (.-classList body)]
(doseq [old ["standing-closed" "standing-reconciled" "standing-outstanding"]]
(.remove classes old))
(.add classes (str "standing-" (clojure.core/name (ending-band)))))))
(def code-version 3)
(defn- check-char [body]
(nth alphabet
(mod (reduce + (map (fn [c] (.indexOf alphabet c)) body)) 32)))
(defn carry-code
"What this reader looks like to the next book, as an accession line."
[]
(let [n (+ (* code-version 4294967296)
(* (get band-code (ending-band) 1) 1073741824)
(* (min 31 (or (:n (companion)) 0)) 33554432)
(* (min 31 (echo)) 1048576)
(* (deed-mask) 32)
(min 31 (quot (score) 10)))
body (b32 n 7)]
(str "016.14 · " (registration) " · "
(subs body 0 4) "-" (subs body 4) (check-char body))))
(defn read-carry
"The other side of it, for the book after this one."
[s]
(let [cleaned (-> (str s) str/upper-case (str/replace #"[^2-9A-Z]" ""))
tail (subs cleaned (max 0 (- (count cleaned) 8)))]
(when (= 8 (count tail))
(let [body (subs tail 0 7)
n (reduce (fn [acc c] (+ (* 32 acc) (.indexOf alphabet c))) 0 body)]
(when (= (nth tail 7) (check-char body))
{:version (quot n 4294967296)
:band (get code-band (mod (quot n 1073741824) 4))
:companion (mod (quot n 33554432) 32)
:echo (mod (quot n 1048576) 32)
:deeds (deeds-from-mask (mod (quot n 32) (bit-shift-left 1 deed-bits)))
:score-floor (* 10 (mod n 32))})))))
;; ---------------------------------------------------------------------
;; Is any of this working
;;
;; Type fedoras.reader.diagnose_BANG_() in the console. Faster than
;; opening the storage inspector and reading JSON, and it says whether
;; the token agrees with the storage, which is the failure that cost an
;; animal.
;; ---------------------------------------------------------------------
(defn diagnose! []
(let [t (param carry-param)]
(js/console.log "storage works: " (storage-works?))
(js/console.log "origin: " (.-origin js/location)
(if (= "file:" (.-protocol js/location))
"— every page may have its own storage"
"— one bucket for the whole book"))
(js/console.log "name: " (pr-str (reader-name)))
(js/console.log "companion: " (pr-str (companion)))
(js/console.log " raw storage: " (pr-str (stored :companion)))
(js/console.log "roster loaded: " (count @animal-names) "animals")
(js/console.log "echo / fortune: " (echo) "/" (fortune) " → standing" (standing))
(js/console.log "withdrawn at: " (if (pos? (epoch)) (epoch) "never")
(if carries-epoch?
""
"— CODEC DROPS THE STAMP, carry.cljs is out of date"))
(js/console.log "rolls: " (pr-str (rolls)))
(js/console.log "token on url: " (or t "none"))
(when t
(js/console.log " unpacks to: "
(pr-str (try (fedoras.carry/unpack t)
(catch :default e (str "THREW: " e))))))
(js/console.log "token we'd emit:" (or (token) "none — pack failed"))
:ok))
;; A handle on `window`, because Scittle keeps its namespaces inside the
;; SCI context and the browser console cannot see into it. There is no
;; `fedoras.reader.diagnose_BANG_()` to call — that is the shape a
;; compiled build would have, and this is an interpreted one.
;;
;; fedoras.diagnose()
;; fedoras.forget()
;;
;; and for anything else, scittle.core.eval_string("(fedoras.reader/...)")
(set! (.-fedoras js/window)
(js-obj "diagnose" (fn [] (diagnose!))
"state" (fn [] (clj->js @state))
"token" (fn [] (token))
"forget" (fn [] (forget!))))
;; ---------------------------------------------------------------------
;; Boot
;; ---------------------------------------------------------------------
(if (withdraw-if-asked!)
;; a hidden frame, doing one job. no token, no links, no painting.
(refresh!)
;; read before anything registers a watch: `on-render!` calls its
;; function once on the spot, and the links watch tidies the query
;; string, so the flag is gone by the time the DOM is ready
(let [withdrew? (boolean (param withdrawn-param))]
(when-not carries-epoch?
(js/console.warn
(str "fedoras: carry.cljs does not round-trip the withdrawal stamp. "
"`forget!` will clear this chapter and every chapter linked from it, "
"but a stale link will not be refused afterwards. "
"Update resources/fedoras/carry.cljs — `pack` needs :epoch in its "
"destructuring and :g in its payload, and `unpack` needs :epoch back out.")))
(import-token!)
(refresh!)
(on-render! ::name paint-name)
(on-render! ::companion paint-companion)
(on-render! ::tokens paint-tokens)
(on-render! ::standing paint-standing!)
(on-render! ::links (fn [] (decorate-links!) (rewrite-address!)))
(if (= "loading" (.-readyState js/document))
(.addEventListener js/document "DOMContentLoaded"
(fn [_]
(note-withdrawal! withdrew?)
(decorate-links!)
(paint-standing!)))
(do (note-withdrawal! withdrew?)
(decorate-links!)))))</script><script type="application/x-scittle">(fedoras.reader/animals! {1 {:animal "Pigeon", :plural "pigeons", :taxonomy "bird", :collective "kit", :other-names ["dusty wings" "coooo"]}, 2 {:animal "Giant Centipede", :plural "centipedes", :taxonomy "arthropod", :collective "colony", :other-names ["clicker" "legs gooo"]}, 3 {:animal "Marmot", :plural "marmots", :taxonomy "rodent", :collective "madness", :other-names ["the alarm" "the fat rat"]}, 4 {:animal "Cat", :plural "cats", :taxonomy "felid", :collective "clowder", :other-names ["the cat" "cat"]}, 5 {:animal "Turkey", :plural "turkeys", :taxonomy "fowl", :collective "rafter", :other-names ["thanksgiving dinner for non vegans" "gobbler"]}, 6 {:animal "Giant Badger", :plural "badgers", :taxonomy "mustelid", :collective "cete", :other-names ["angry grandpa" "stripes"]}, 7 {:animal "Giant Weasel", :plural "weasels", :taxonomy "mustelid", :collective "sneak", :other-names ["the scout" "slenderman" "the ermine"]}, 8 {:animal "Fox", :plural "foxes", :taxonomy "canid", :collective "skulk", :other-names ["foxxxy" "spry foot"]}, 9 {:animal "Wolverine", :plural "wolverines", :taxonomy "mustelid", :collective "gang", :other-names ["the small trouble"]}, 10 {:animal "Dog", :plural "dogs", :taxonomy "canid", :collective "pack", :other-names ["the dog" "the ordinary dog"]}, 11 {:animal "Python", :plural "pythons", :taxonomy "serpent", :collective "knot", :other-names ["ssSSssSsss" "coilssss"]}, 12 {:animal "Mule", :plural "mules", :taxonomy "equid", :collective "barren", :other-names ["dapple" "HeeHaw :("]}, 13 {:animal "Lynx", :plural "lynxes", :taxonomy "felid", :collective "clowder", :other-names ["tufts" "yelper"]}, 14 {:animal "Ape", :plural "apes", :taxonomy "primate", :collective "shrewdness", :other-names ["treecrawler"]}, 15 {:animal "Horse", :plural "horses", :taxonomy "equid", :collective "harras", :other-names ["rocinante" "the one nobody rides"]}, 16 {:animal "Moose", :plural "moose", :taxonomy "cervid", :collective "herd", :other-names ["its a giant moose"]}, 17 {:animal "Wyrmling", :plural "wyrmlings", :taxonomy "draconic", :collective "clutch", :other-names ["the wyrmling" "scales"]}, 18 {:animal "Falcon", :plural "falcons", :taxonomy "raptor", :collective "cast", :other-names ["the raptor" "true sight"]}, 19 {:animal "Wolf", :plural "wolves", :taxonomy "canid", :collective "pack", :other-names ["the wolf" "the packleader"]}, 20 {:animal "Bear", :plural "bears", :taxonomy "ursid", :collective "sloth", :other-names ["the bear" "the citadel"]}})</script></div></div>
```
# Scene 1 — The Second Week
```{=html}
<span style="display:none;"></span>
```
```{=html}
<blockquote class="handbook"><p class="rule-number">The Fedora Handbook, Rule #2</p><p class="rule-text">“Every great thinker was misunderstood in his own time. I have arranged to be misunderstood in advance.”</p></blockquote>
```
```{=html}
<div class="scene"><div class="screenplay"><p class="slug">INT. PLANT SERVICES — MONDAY, 6:00 A.M.</p></div><div class="screenplay"><p class="action">A long low room under the north end of campus. Concrete floor sloping to a drain. Four sets of waders hanging by the shoulders like people.</p><p class="action">The whole of one wall is drawings. Left unframed. Rolled, in racks, in tubes, hundreds of them, each with a building and a date on the end of it in four different hands.</p><p class="action">HOLLIS has one unrolled on the bench with a mug on one corner and a hammer on the other, and he does not look up when <span class="pc-name" data-case="pc" data-pc="-first">Owen</span> comes in and does not ask who he is.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">You're the Provisional. Six o'clock is six</p><p class="line">o'clock.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">Sorry.</p></div></div><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">It's two minutes past. I'm not making a thing of</p><p class="line">it, I'm telling you what it is.</p></div></div></div><div class="screenplay"><p class="action beat">He goes back to the drawing.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">Do you know what this is?</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">A plan.</p></div></div><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">It's Meridian Hall, nineteen forty-one, services.</p><p class="line">Every pipe and every run and every box in that</p><p class="line">building, drawn by a man who never saw it built.</p></div></div></div><div class="screenplay"><p class="action">He puts a finger on a line that goes off the edge of the sheet.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">And that is where it stops being true, and the job</p><p class="line">is knowing where.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">Isn't there a new one?</p></div></div><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">There's a new one for the bits they've done since.</p><p class="line">There's one for forty-one, one for sixty-eight,</p><p class="line">two for the nineties and a folder of loose sheets</p><p class="line">that nobody signed. None of them agree and all of</p><p class="line">them are right about something.</p></div></div></div><div class="screenplay"><p class="action beat">He rolls it and puts it back in the rack and takes another one out without looking at the labels.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">Four hundred contactors under this campus. I've</p><p class="line">asked for eighty a year for eleven years. What I</p><p class="line">get is a map that's wrong and a lad in October,</p><p class="line">and the maps last longer.</p></div></div></div><div class="screenplay"><p class="transition">Cut to:</p></div><div class="screenplay"><p class="slug">INT. MERIDIAN HALL — BASEMENT — 6:40 A.M.</p></div><div class="screenplay"><p class="action">Wet. A torch that wet is worse than no torch. <span class="pc-name" data-case="pc" data-pc="-first">Owen</span> has a photocopy of a sheet of 1941 folded into his pocket and a galvanised bucket in his hand.</p><p class="action">The job mainly consistst of two responsibilities: The bucket goes under the pipe by the stair, which has been coming through since June. Then he walks the run on the sheet and marks where the sheet is lying.</p><p class="action">It lies twice in forty feet. A branch that is not on the sheet. A box on the sheet that is not on the wall.</p><p class="action">There is already a bucket under the pipe. He puts his next to it.</p><p class="action">The floor slopes away to the south, further than a floor needs to, and the sheet stops at a line marked in pencil and the pencil is not the same pencil as the rest of it.</p></div><div class="screenplay"><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><p class="paren">(calling up the stair)</p><div class="lines"><p class="line">The drawing stops.</p></div></div><div class="dialogue"><p class="character">HOLLIS (O.S.)</p><div class="lines"><p class="line">Yes.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">Stops at what?</p></div></div><div class="dialogue"><p class="character">HOLLIS (O.S.)</p><div class="lines"><p class="line">At the fill.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">What's the fill?</p></div></div><div class="dialogue"><p class="character">HOLLIS (O.S.)</p><div class="lines"><p class="line">"What's under it?", "What's it made of?" As if</p><p class="line">you're the first to ask. Bring the sheet up, don't</p><p class="line">get it wet.</p></div></div><div class="dialogue"><p class="character">HOLLIS (O.S.)</p><div class="lines"><p class="line">The fill is just that which the college doesn't</p><p class="line">need anymore All the waste and refuse. It's best</p><p class="line">to pay it no heed,</p></div></div><div class="dialogue"><p class="character">HOLLIS (O.S.)</p><p class="paren">(Laughing, the soung getting staticky)</p><div class="lines"><p class="line">"Unless 'ye be Meridian..."</p></div></div></div><div class="screenplay"><p class="transition">Cut to:</p></div><div class="screenplay"><p class="slug">INT. PLANT SERVICES — 7:20 A.M.</p></div><div class="screenplay"><p class="action">Hollis takes the sheet, looks at the two marks, and writes on the drawing in pencil, in the fourth hand.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">Right. That's the job. That and the bucket.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">How long has that branch not been on there?</p></div></div><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">Since before me. I've been forty-one years and</p><p class="line">I've put about nine hundred marks on these and the</p><p class="line">man before me put more.</p></div></div></div><div class="screenplay"><p class="action beat">He hangs it back in the rack.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">What did you fix, then? They said you fixed</p><p class="line">something.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">The water on my block. It stopped in February and</p><p class="line">nobody came, and then it came back on.</p></div></div><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">Came back on how?</p></div></div></div><div class="screenplay"><p class="action beat">This is the part <span class="pc-name" data-case="pc" data-pc="-first">Owen</span> has never had a great answer to.</p></div><div class="screenplay"><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><p class="paren">(With a closed fist and a pounding gesture)</p><div class="lines"><p class="line">I hit it, kinda like this.</p></div></div></div><div class="screenplay"><p class="action">Hollis puts the mug down. It is the first time he has shown any real interest in the conversation.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><p class="paren">(With hands on his hips, and another at his beard)</p><div class="lines"><p class="line">Whereabouts?</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">The flat panel on the side, near the bottom.</p></div></div><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">Yyyyep, thought so. That could definitely be a</p><p class="line">contactor. There'll be a spring in it. And by God</p><p class="line">do those springs stick- if you catch it near</p><p class="line">enough... *click!* it drops. Just like that, and</p><p class="line">the pump goes.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">So that's what it was.</p></div></div><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">Could be. Could be it came back on and you were</p><p class="line">stood right there in front of it. Forty-one years</p><p class="line">and I've seen it both ways and I've never once</p><p class="line">been able to tell you which.</p></div></div></div><div class="screenplay"><p class="action beat">He picks the mug up again.</p></div><div class="screenplay"><div class="dialogue"><p class="character">HOLLIS</p><div class="lines"><p class="line">What I'd say is you touched it. Nobody touches</p><p class="line">anything.</p></div></div></div><div class="screenplay"><p class="transition">Cut to:</p></div><div class="screenplay"><p class="slug">INT. MERIDIAN HALL — CS 101 — MONDAY, 8:00 A.M.</p></div><div class="screenplay"><p class="action"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span> comes in wet to the knee. Nobody asks.</p></div><div class="screenplay"><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">We did the first three last week.</p><p class="line">These three draw. Starting with program four:</p></div></div></div><div class="screenplay"><p class="action">Dots appear on the page, one at a time, faster than the eye can keep up with. For a moment it is nothing. Then it forms equal triangles going in, and in, and in.</p></div><div class="screenplay"><div class="dialogue"><p class="character">A STUDENT</p><div class="lines"><p class="line">Is it a picture of something?</p></div></div><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">It's ten thousand dots and one rule. I'm not</p><p class="line">telling you the rule, because that is the point of</p><p class="line">the class.</p></div></div><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">Five.</p></div></div></div><div class="screenplay"><p class="action">Fifteen numbers and a hole. She slides four of them, then tries to slide one that is not next to the hole, and the page does not let her.</p></div><div class="screenplay"><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">See that? It said no.</p><p class="line">That's the assignment.</p></div></div><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">Last one, and then you can go back to sleep.</p></div></div></div><div class="screenplay"><p class="action">A square. Inside it a smaller square, turned. Inside that, a smaller one, turned the same way again, and again, and the middle of the page is filled with them.</p></div><div class="screenplay"><div class="dialogue"><p class="character">A STUDENT</p><div class="lines"><p class="line">How do you get it to turn?</p></div></div><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">Ask your helps how to move things on a canvas.</p></div></div><div class="dialogue"><p class="character">A STUDENT</p><div class="lines"><p class="line">Do we need the geometry?</p></div></div></div><div class="screenplay"><p class="action beat">Reyes puts the page away and looks at the student.</p></div><div class="screenplay"><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">You only need one idea. There's a hard way that</p><p class="line">works and an easy way that works and both get the</p><p class="line">marks, so take whichever one you can get to the</p><p class="line">end of.</p></div></div><div class="dialogue"><p class="character">A STUDENT</p><div class="lines"><p class="line">Which did you do?</p></div></div><div class="dialogue"><p class="character">REYES</p><div class="lines"><p class="line">The hard way. Twice.</p></div></div></div><div class="screenplay"><p class="transition">Cut to:</p></div><div class="screenplay"><p class="slug">INT. WHITLOCK HALL — LECTURE ROOM 1 — MONDAY, 4:00 P.M.</p></div><div class="screenplay"><p class="action">Two hundred and forty seats. Nine people in them.</p><p class="action">PROFESSOR WHITLOCK is old and takes a while to stand. There is a wooden box on the desk in front of him with photographs in it and he takes them out one at a time and holds them up, and nine people at the front of a room built for two hundred and forty lean forward to see a photograph the size of a hand.</p><p class="action">MAYA is in the second row because Carter's bench work is on Tuesdays now. She has brought <span class="pc-name" data-case="pc" data-pc="-first">Owen</span>, who has not been to a lecture nobody made him go to.</p><p class="action">LENA is in the front row and is not taking notes. She has a flat grey box on her knees with forty of the photographs in it in sleeves, which she made.</p></div><div class="screenplay"><div class="dialogue"><p class="character">WHITLOCK</p><div class="lines"><p class="line">This is the ground. Before any of it. 15 acres,</p><p class="line">flat, which is why they took it.</p></div></div></div><div class="screenplay"><p class="action">He holds up a photograph of a field.</p></div><div class="screenplay"><div class="dialogue"><p class="character">WHITLOCK</p><div class="lines"><p class="line">And this is the same ground the following spring,</p><p class="line">and you can see the line of the refectory going</p><p class="line">in, and - Miss Novak, is that the one?</p></div></div><div class="dialogue"><p class="character">LENA</p><p class="paren">(Leans in for a closer look)</p><div class="lines"><p class="line">Uhhh, yeah that's the one.</p></div></div><div class="dialogue"><p class="character">WHITLOCK</p><div class="lines"><p class="line">Miss Novak has copied these because the originals</p><p class="line">are fading. They are fading because nobody has</p><p class="line">kept them at the right temperature for 50 odd</p><p class="line">years and not because of anything sinister, which</p><p class="line">I say because somebody asks every year.</p></div></div></div><div class="screenplay"><p class="action beat">Nobody laughs, nor was he being funny.</p><p class="action">He holds up the second photograph. It is the same field with a trench across it and a stack of brick beside the trench.</p></div><div class="screenplay"><div class="dialogue"><p class="character">MAYA</p><p class="paren">(quietly, to <span class="pc-name" data-case="pc" data-pc="-first">Owen</span>)</p><div class="lines"><p class="line">That's not 15 acres of nothing...</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">What?</p></div></div><div class="dialogue"><p class="character">MAYA</p><div class="lines"><p class="line">There's a stack of brick in it. Nobody carries</p><p class="line">brick onto a field. You take brick off a field.</p></div></div></div><div class="screenplay"><p class="action beat">Whitlock has heard her, because the room is nine people.</p></div><div class="screenplay"><div class="dialogue"><p class="character">WHITLOCK</p><div class="lines"><p class="line">Yes. There was something here. It is in every</p><p class="line">history of the institution, in one sentence, and</p><p class="line">the sentence is that the site was cleared.</p></div></div><div class="dialogue"><p class="character">MAYA</p><div class="lines"><p class="line">Cleared of what?</p></div></div><div class="dialogue"><p class="character">WHITLOCK</p><div class="lines"><p class="line">That's a good question. I have been asking it</p><p class="line">since nineteen sixty-two, and I would like you to</p><p class="line">understand that I am not being mysterious with</p><p class="line">you. I do not know.</p></div></div></div><div class="screenplay"><p class="action beat">He puts the photograph back in the box.</p></div><div class="screenplay"><div class="dialogue"><p class="character">WHITLOCK</p><div class="lines"><p class="line">Miss Novak has been through the whole box twice</p><p class="line">and she will tell you the same.</p></div></div><div class="dialogue"><p class="character">LENA</p><p class="paren">(without turning round)</p><div class="lines"><p class="line">Forty-one photographs. Nothing after the trench.</p></div></div></div><div class="screenplay"><p class="transition">Cut to:</p></div><div class="screenplay"><p class="slug">EXT. WHITLOCK HALL — THE STEPS — 5:10 P.M.</p></div><div class="screenplay"><p class="action">Lena closes the camera with two elastic bands, because the clasp has been broken since before the camera was hers. She has been holding it shut like this since the day she got it and has stopped noticing she does it.</p></div><div class="screenplay"><div class="dialogue"><p class="character">MAYA</p><div class="lines"><p class="line">Why are you doing it?</p></div></div><div class="dialogue"><p class="character">LENA</p><div class="lines"><p class="line">Because he asked me. He came to the print shop</p><p class="line">himself, at his speed, up the four flights of</p><p class="line">stairs, and asked whether I would copy some</p><p class="line">photographs. I don't know what else I'd do.</p></div></div></div><div class="screenplay"><p class="action beat">She puts the second band on.</p></div><div class="screenplay"><div class="dialogue"><p class="character">MAYA</p><div class="lines"><p class="line">And the photographs?</p></div></div><div class="dialogue"><p class="character">LENA</p><div class="lines"><p class="line">The photographs are the other reason. There are</p><p class="line">forty-one of them and there ought to be more.</p></div></div><div class="dialogue"><p class="character"><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></p><div class="lines"><p class="line">Why ought there?</p></div></div><div class="dialogue"><p class="character">LENA</p><div class="lines"><p class="line">Because they are numbered on the back and the</p><p class="line">numbers go to seventy-three.</p></div></div></div><div class="screenplay"><p class="action">She puts the box under her arm and goes.</p></div><div class="screenplay"><p class="transition">Blackout.</p></div><div class="screenplay"><p class="action">Tuesday he starts the squares program, using lines, for the simple fact that a square is four lines and he knows how to describe a line mathematically: where it starts and how steep it is.</p></div></div>
```
::: {.sourceClojure}
```clojure
(defn slope [[x1 y1] [x2 y2]]
(/ (- y2 y1) (- x2 x1)))
(slope [0 0] [100 0]) ;; 0
(slope [0 0] [0 100]) ;; ?
```
:::
```{=html}
<div class="artifact terminal"><p class="term-in"><span>$ clj -M -e "(slope [0 0] [0 100])"</span></p><p class="term-out"><span>Execution error (ArithmeticException)</span></p><p class="term-out"><span>Divide by zero</span></p><p class="term-in"><span>$</span></p></div>
```
```{=html}
<div class="scene"><div class="screenplay"><p class="action">Two of the four sides of a square go straight up. A line that goes straight up goes up any amount you like for none across, and the page will not have it. By Thursday there are four special cases and the corners are in the wrong order and the whole thing leans.</p></div></div>
```
```{=html}
<div class="artifact discord"><div class="discord-head"><span class="discord-server">FEDORA SOCIETY</span><span class="discord-channel">#general</span></div><div class="discord-body"><div class="discord-msg"><p class="discord-meta"><span class="discord-who"><span><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></span></span><span class="discord-at">1:14 AM</span></p><div class="discord-text"><p><span>does anyone know how to do a line thats straight up</span></p></div></div><div class="discord-msg"><p class="discord-meta"><span class="discord-who"><span>Derek</span></span><span class="discord-at">1:19 AM</span></p><div class="discord-text"><p><span>up how</span></p></div></div><div class="discord-msg"><p class="discord-meta"><span class="discord-who"><span><span class="pc-name" data-case="pc" data-pc="-first">Owen</span></span></span><span class="discord-at">1:19 AM</span></p><div class="discord-text"><p><span>straight up. vertical</span></p></div></div><div class="discord-msg"><p class="discord-meta"><span class="discord-who"><span>Derek</span></span><span class="discord-at">1:22 AM</span></p><div class="discord-text"><p><span>draw it sideways then turn the page</span></p></div></div><div class="discord-msg"><p class="discord-meta"><span class="discord-who"><span>Miles</span></span><span class="discord-at">1:26 AM</span></p><div class="discord-text"><p><span>^</span></p></div></div><div class="discord-msg"><p class="discord-meta"><span class="discord-who"><span>Victor</span></span><span class="discord-role">PRESIDENT</span><span class="discord-at">8:02 AM</span></p><div class="discord-text"><p><span>Coursework is not a matter for #general.</span></p><p><span>There is no channel for coursework. I will consider one.</span></p></div></div></div></div>
```
```{=html}
<div class="scene"><div class="screenplay"><p class="action">Friday, in the basement, with the second bucket, he is thinking about a man putting a pencil mark on a drawing that is wrong, in the fourth hand, without stopping to work out why it is wrong.</p><p class="action">He doesn't necessarily need the angle of anything. He needs a mark a little way along each side, and the four marks are the next square, and then he does the same thing to those.</p><p class="action">First, though, the thing he knows he is going to want, which is a way to do something, then do it again to what came out, and keep every step on the way, because he would like to watch the squares arrive one at a time rather than all at once at the end.</p></div></div>
```
```{=html}
<div class="scene-code"><pre><code>(defn each
"Start with a thing. Do the thing to it, n times. Keep all of them."
[start f n]
(reduce (fn [acc _] (conj acc (f (peek acc)))) [start] (range n)))
(each 1 (fn [x] (* 2 x)) 8)</code></pre></div>
```
```{=html}
<div class="scene"><div class="screenplay"><p class="action">Eleven lines of nothing, written on a Tuesday, used for the rest of the year. In the page it is called frames!, because the page draws between the steps.</p></div></div>
```
```{=html}
<div class="scene-code"><pre><code>(defn corners [size]
[[0 0] [size 0] [size size] [0 size]])
(defn inset
" Walk a little way along each side, in order, and keep where you got
to. The corner you are walking towards is the next one round."
[pts t]
(mapv (fn [[x1 y1] [x2 y2]]
[(+ x1 (* t (- x2 x1)))
(+ y1 (* t (- y2 y1)))])
pts
(conj (subvec pts 1) (nth pts 0))))
(inset (corners 100) 0.12)
(def rings
(each (corners 100) (fn [square] (inset square 0.12)) 39))
(count rings)
(kind/hiccup
[:svg {:viewBox " -6 -6 112 112 " :width 380
:xmlns "http://www.w3.org/2000/svg"}
[:rect {:x -6 :y -6 :width 112 :height 112 :style {:fill "var(--paper)"}}]
(for [pts rings]
[:polygon {:points (str/join " " (map (fn [[x y]] (str x "," y)) pts))
:stroke-width 0.4
:style {:fill "none" :stroke "var(--ink)"}}])])</code></pre></div>
```
::: {.printedClojure}
```clojure
[1 2 4 8 16 32 64 128 256]
```
:::
::: {.printedClojure}
```clojure
[[12.0 0.0] [100.0 12.0] [88.0 100.0] [0.0 88.0]]
```
:::
::: {.printedClojure}
```clojure
40
```
:::
```{=html}
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```
```{=html}
<div class="scene"><div class="screenplay"><p class="action">The page gives you somewhere to draw and four things to draw with. There is nothing in it that is hidden.</p></div><div><script type="application/x-scittle">(ns fedoras.sketch
"Editable ClojureScript that draws.
The live cells elsewhere in the book evaluate an expression and print
what it returned, which is fine for a list and useless for a picture.
A sketch cell gives the code a canvas and five things to draw with,
and then gets out of the way: what the reader edits is the same
algorithm that ran on the JVM at build time, in the same language,
and it runs in front of them.
What the page provides, and the scene says so out loud because Reyes
said it in class:
(clear!) wipe it
(ink! \"#1c1f24\") colour
(dot x y) one mark, in world coordinates
(poly [[x y] ...]) a closed outline
(frames! total per f) call (f i) total times, per of them a frame
Nothing else is injected. Everything above the fold in the cell is
the reader's.
WHERE THE CODE IS. All of it is here, in one file read twice. The
build reads the :clj half, which writes the markup and, for each cell,
a header binding the short names to that cell's own canvas or piece of
page. The page reads the :cljs half, because the build ships this file
to it as it stands: the drawing kit the headers call, and the runner
behind every Run button."
#?(:clj (:require [clojure.string :as str]
[fedoras.state :as state]
[scicloj.kindly.v4.kind :as kind])))
;; ---------------------------------------------------------------------
;; The build: headers and markup
;; ---------------------------------------------------------------------
#?(:clj
(do
(defn canvas-header
"The short names a sketch cell may use, bound to its own canvas.
Built as Clojure forms rather than as a string, so it cannot be
unbalanced and can be read back and printed."
[id world-w world-h]
[(list 'def 'C (list 'fedoras.sketch/mount id world-w world-h))
'(def cv (:cv C))
'(def ctx (:ctx C))
'(def CW (:cw C))
'(def CH (:ch C))
'(def SX (:sx C))
'(def SY (:sy C))
'(defn clear! [] (fedoras.sketch/clear! C))
'(defn ink! [c] (fedoras.sketch/ink! C c))
'(defn dot ([x y] (fedoras.sketch/dot C x y)) ([x y s] (fedoras.sketch/dot C x y s)))
'(defn poly [pts] (fedoras.sketch/poly C pts))
'(defn frames! [total per f] (fedoras.sketch/frames! C total per f))
'(defn on-pointer! [f] (fedoras.sketch/on-pointer! C f))
'(def page-ink (fedoras.sketch/page-ink C))
'(clear!)
'(ink! page-ink)
'(fedoras.sketch/line-width! C 0.8)])
(defn page-header
"The names a page cell may use. No canvas: a piece of the page."
[id]
[(list 'def 'root (list '.getElementById 'js/document (str id "-out")))
'(defn html! [s] (set! (.-innerHTML root) s))
'(defn on! [id f]
(let [e (.getElementById js/document id)]
(when e (set! (.-onclick e) (fn [_] (f))))))
'(defn fetch [k]
(try
(let [v (.getItem js/localStorage (str "fedoras." k))]
(when v (read-string v)))
(catch :default _ nil)))
'(defn store! [k v]
(try (.setItem js/localStorage (str "fedoras." k) (pr-str v))
(catch :default _ nil))
v)])
(defn- header-text [forms]
(str/join "\n" (map pr-str (cons '(in-ns 'fedoras.sketch-runner) forms))))
(defn primitives
"What the page hands a cell, printed, so that nothing in the book is
doing something the reader cannot look at."
([] (primitives 100 100))
([world-w world-h]
(kind/code (header-text (canvas-header "the-page" world-w world-h)))))
(defn cell
"An editable ClojureScript sketch with a canvas under it.
(sketch/cell {:id \"chaos\" :label \"CHAOS.CLJS\" :world [100 86.6]}
\"(dot 50 40)\")"
[{:keys [id label world w h rows]
:or {id "sketch" world [100 100] w 420 h 380 rows 16}}
code]
(let [[ww wh] world]
(kind/hiccup
[:div
(state/source "fedoras/sketch.cljc")
[:div.sketch {:id id}
[:div.roll-head
[:span.roll-label (or label "SKETCH")]
[:span.roll-dc (str ww " × " wh)]]
[:textarea {:id (str id "-src") :class "live-src" :rows rows :spellcheck "false"}
(str/trim code)]
[:div.live-bar
[:button.live-run "Run"]]
[:canvas {:id (str id "-canvas") :width w :height h}]
[:pre {:id (str id "-out") :class "live-out"}]]
(state/call 'fedoras.sketch/cell! id (header-text (canvas-header id ww wh)))])))
(defn page
"An editable ClojureScript cell with a piece of page under it instead
of a canvas. The header gives the code five things:
root the div it owns
(html! s) put markup in it
(on! id f) wire a click
(fetch k) read something the reader saved
(store! k v) save something, and it is still there tomorrow
Everything else in the cell belongs to the reader."
[{:keys [id label rows] :or {id "page" rows 20}} code]
(kind/hiccup
[:div
(state/source "fedoras/sketch.cljc")
[:div.sketch {:id id}
[:div.roll-head
[:span.roll-label (or label "PAGE")]
[:span.roll-dc "cljs"]]
[:textarea {:id (str id "-src") :class "live-src" :rows rows :spellcheck "false"}
(str/trim code)]
[:div.live-bar
[:button.live-run "Run"]]
[:div {:id (str id "-out") :class "sketch-page"}]
[:pre {:id (str id "-res") :class "live-out"}]]
(state/call 'fedoras.sketch/cell! id (header-text (page-header id)))]))))
;; ---------------------------------------------------------------------
;; The page: the drawing kit and the runner
;; ---------------------------------------------------------------------
#?(:cljs
(do
(defonce counters
(atom {}))
(defn- counters-for
"The frame counters of one canvas: made the first time it is mounted
and kept for every Run after, so that each press of Run takes the
next number and the loop the last press started sees it and stops."
[id]
(or (get @counters id)
(let [made {:run (atom 0) :i (atom 0)}]
(swap! counters assoc id made)
made)))
(defn mount
"Everything one cell needs, from the id of its canvas and the size of
the world it draws in. Every drawing function below takes the map
this returns."
[id world-w world-h]
(let [cv (.getElementById js/document (str id "-canvas"))
ctx (.getContext cv "2d")
cw (.-width cv)
ch (.-height cv)]
(merge {:cv cv :ctx ctx :cw cw :ch ch
:sx (/ cw world-w)
:sy (/ ch world-h)}
(counters-for id))))
(defn ink!
"Both fill and stroke, because a cell that sets one and not the other
is a cell that draws in two colours by accident."
[{:keys [ctx]} colour]
(set! (.-fillStyle ctx) colour)
(set! (.-strokeStyle ctx) colour))
(defn page-ink
"Whatever colour the surrounding prose is, so a drawing belongs to the
page it is on and follows it into dark mode."
[{:keys [cv]}]
(.-color (js/getComputedStyle cv)))
(defn clear! [{:keys [ctx cw ch]}]
(.clearRect ctx 0 0 cw ch))
(defn dot
([c x y] (dot c x y 1.2))
([{:keys [ctx sx sy ch]} x y size]
(.fillRect ctx (* x sx) (- ch (* y sy)) size size)))
(defn poly
"A closed outline through the points, in world coordinates."
[{:keys [ctx sx sy ch]} pts]
(when (seq pts)
(let [[fx fy] (first pts)]
(.beginPath ctx)
(.moveTo ctx (* fx sx) (- ch (* fy sy)))
(doseq [[x y] (rest pts)]
(.lineTo ctx (* x sx) (- ch (* y sy))))
(.closePath ctx)
(.stroke ctx))))
(defn line-width! [{:keys [ctx]} w]
(set! (.-lineWidth ctx) w))
(defn- tick! [{:keys [run i] :as c} generation total per f]
(when (= generation @run)
(dotimes [_ per]
(when (< @i total) (f @i) (swap! i inc)))
(when (< @i total)
(js/requestAnimationFrame (fn [] (tick! c generation total per f)))))
nil)
(defn frames!
"Call (f i) total times, per of them per frame.
Pressing Run again retires the loop that is already going. Without
that, a cell run twice advances twice per frame and looks broken in a
way nobody can debug from the outside."
[{:keys [run i] :as c} total per f]
(let [generation (swap! run inc)]
(reset! i 0)
(tick! c generation total per f))
nil)
(defn on-pointer!
"Pointer position in world coordinates, which is what a cell wants and
never what the event gives it."
[{:keys [cv sx sy]} f]
(set! (.-onmousemove cv)
(fn [e]
(f (/ (.-offsetX e) sx)
(- (/ (.-height cv) sy) (/ (.-offsetY e) sy))))))
(defonce headers
(atom {}))
(defn- element
[id]
(.getElementById js/document id))
(defn- line-count
[text]
(count (re-seq #"\n" text)))
(defn- error-text
"An error as the reader should see it: the message, and the line of
their own code it came from, when there is one."
[error header-lines]
(let [line (:line (ex-data error))]
(str (or (ex-message error) (str error))
(when (and line (> line header-lines))
(str " (line " (- line header-lines) ")")))))
(defn run-cell!
"Cell `id`'s header, then the reader's code, with what came back
printed under the cell, or the error, counted in the reader's lines."
[id]
(let [header (get @headers id)
out (or (element (str id "-res")) (element (str id "-out")))
source (.-value (element (str id "-src")))]
(set! (.-textContent out)
(try
;; load-string is Scittle's own; plain ClojureScript has none
(let [value #_{:clj-kondo/ignore [:unresolved-symbol]} (load-string (str header "\n" source))]
(if (nil? value) "" (str value)))
(catch :default error
(error-text error (inc (line-count header))))))))
(defn- prepare-canvas!
"Give a sketch cell's canvas its drawing context while the page
loads, so that the first Run draws on a canvas the browser has
already shown once. A context made at the moment of the first
drawing loses that drawing in Firefox: the first frames of the
first Run never appear."
[id]
(when-let [cv (element (str id "-canvas"))]
(.clearRect (.getContext cv "2d") 0 0 (.-width cv) (.-height cv))))
(defn cell!
"Keep cell `id`'s header and wire its Run button, and the first time
the cell is seen, prepare its canvas, if it has one. Only the first
time, because preparing clears, and a canvas that is already drawing
must not be cleared under it."
[id header]
(let [first-time? (not (contains? @headers id))]
(swap! headers assoc id header)
(when-let [button (some-> (element id) (.querySelector ".live-run"))]
(set! (.-onclick button) (fn [_] (run-cell! id))))
(when first-time?
(prepare-canvas! id))))))</script><div class="sketch" id="squares"><div class="roll-head"><span class="roll-label">SQUARES.CLJS</span><span class="roll-dc">100 × 100</span></div><textarea class="live-src" id="squares-src" rows="16" spellcheck="false">(defn inset [pts t]
(mapv (fn [[x1 y1] [x2 y2]]
[(+ x1 (* t (- x2 x1)))
(+ y1 (* t (- y2 y1)))])
pts
(conj (subvec pts 1) (nth pts 0))))
(def square (atom [[0 0] [100 0] [100 100] [0 100]]))
;; 40 squares, one a frame. Try 0.4 instead of 0.12.
(frames! 40 1
(fn [_]
(poly @square)
(swap! square inset 0.12)))</textarea><div class="live-bar"><button class="live-run">Run</button></div><canvas height="380" id="squares-canvas" width="420"></canvas><pre class="live-out" id="squares-out"></pre></div><script type="application/x-scittle">(if-let [mount (resolve (quote fedoras.sketch/cell!))] (mount "squares" "(in-ns (quote fedoras.sketch-runner))\n(def C (fedoras.sketch/mount \"squares\" 100 100))\n(def cv (:cv C))\n(def ctx (:ctx C))\n(def CW (:cw C))\n(def CH (:ch C))\n(def SX (:sx C))\n(def SY (:sy C))\n(defn clear! [] (fedoras.sketch/clear! C))\n(defn ink! [c] (fedoras.sketch/ink! C c))\n(defn dot ([x y] (fedoras.sketch/dot C x y)) ([x y s] (fedoras.sketch/dot C x y s)))\n(defn poly [pts] (fedoras.sketch/poly C pts))\n(defn frames! [total per f] (fedoras.sketch/frames! C total per f))\n(defn on-pointer! [f] (fedoras.sketch/on-pointer! C f))\n(def page-ink (fedoras.sketch/page-ink C))\n(clear!)\n(ink! page-ink)\n(fedoras.sketch/line-width! C 0.8)") (js/console.error "fedoras: fedoras.sketch/cell! is not on this page. Either the file that declares it was never shipped, or the namespace inside it does not match the path it was shipped from."))</script></div><div class="screenplay"><p class="action">No slope in it anywhere and it doesn't maintain any conception of which way a side is pointing. It turns. He did not tell it to turn and he cannot entirely say why it turns, and he sits looking at it for longer than the assignment took.</p></div></div>
```