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1. // plugins/web/compile.hl — THE FRAMEWORK COMPILES EACH COMPONENT.
2. //
3. // Mission 313 (the creator, 15 Sep 14:30: "clientside interpreter + table against
4. // component code per component, no tables needed"). The old hl:web ships ONE generic client
5. // that walks a tree the seed carries: it pairs elements with nodes, asks a table which
6. // members each element shows, asks `view.value` what each bound spot holds, and does it
7. // again on every paint. hl:web ships the ANSWERS instead — this file writes each
8. // component's own code, once, where the old hl:web would have walked.
9. //
10. // WHAT IS EMITTED, per component, beside the class `hlJs` compiled:
11. //
12. // v(c,m,o,host,i,rows,rk,fill,cr,opt) the component's View, unrolled: one
13. // statement per element, per handler, per
14. // bound spot. `cr` false CLAIMS the server's
15. // DOM (take host.children[i], step on), `cr`
16. // true CREATES it — the two walks the old hl:web
17. // spells out separately, which differ only in
18. // where an element comes from.
19. // b["<for site>"] one `for` body — the row factory the keyed
20. // region builds a row with.
21. // t/e["<if site>"] an `if`'s two branches.
22. // f["<reference site>"] the fragment this component writes into a
23. // child's `slot` — built in THIS frame, which
24. // is why it is this component's code.
25. // p["<element site>"] the paint statements: `p` writes what one
26. // member feeds (the old hl:web's paint(&m,s,name)),
27. // `r` rewrites a row's element where the DOM
28. // does not already hold it (rowPaint).
29. //
30. // The generated code calls a FIXED runtime (client.hl) for everything that is not this
31. // component: the mount records, the keyed region diff, the binding edges, the
32. // derivations, the socket, navigation. It never looks anything up in a table — the
33. // names, the sites and the write sets are written into the statements.
34. //
35. // It is TEXT the framework produces, served from memory beside the module (WebFramework
36. // `module`), never a JavaScript file under plugins/.
37. import { newline, tab } from './view.hl'
38. import View from './view.hl'
40. // ---- the emitted half --------------------------------------------------------------
41. module(gen, key, nodes) {
42. fns = [] // the sub-walks: row bodies, if branches, fills
43. done = {}
44. rowVars = []
45. tbl = tableOf(gen, key) // what the language says about this file, read once
46. regions = regionIndex(tbl) // a `for`'s list reads, an `if`'s condition reads
47. // A SHELL'S VIEW IS A `body` ELEMENT and the document already has one: the walk runs
48. // against document.body itself, so the root list is that element's children and the
49. // element only takes the marks a region rebuild on it would need.
50. let roots = nodes
51. let bodySite = null
52. if (nodes.length == 1 && nodes[0].k == 'el' && nodes[0].tag == 'body') {
53. roots = nodes[0].children
54. bodySite = nodes[0].site
55. }
56. let root = walkTop(key, roots)
57. if (bodySite != null) {
58. root = root.replace('let r=rows;', 'let r=rows;await c.markHost(m,host,' + str(bodySite) + ');')
59. }
60. let src = ';(function(){var g=(typeof globalThis!=="undefined"?globalThis:window);'
61. src = src + 'var C=(g.__hlC=g.__hlC||{});'
62. // the element a claim takes or a create makes — the one shape both walks share
63. // THE PRELUDE, one per module: the element a claim takes or a create makes, and the
64. // two reads. A read written out in full — `(r["title"]!=null?r["title"]:inst["title"])`
65. // — is 45 bytes and a component's View holds dozens of them; named, it is 16. The
66. // rule is the same rule (a `for` row variable in scope wins over a member of the
67. // same name, and a field path walks into it), spelled once.
68. // A claim also moves the host's CURSOR — the last node the walk took there — which is
69. // where a text leaf and a region's mark are looked for next (client.hl `leafNode`,
70. // `markAt`).
71. src = src + 'function A(cr,host,i,tag){if(cr){return document.createElement(tag);}var e=host.children[i];if(e!=null){host.__hlCur=e;}return e;}'
72. src = src + 'function S(v){return v==null?"":""+v;}'
73. src = src + 'function RV(r,q,n){return r[n]!=null?r[n]:q[n];}'
74. src = src + 'function RF(r,q,n,p){var v=RV(r,q,n);for(var k=0;k<p.length;k++){if(v==null)return null;v=v[p[k]];}return v;}'
75. src = src + 'var B={},T={},E={},F={},P={};'
76. // ONE FUNCTION PER LIST, however many sites reach it: a nested walk is written once
77. // and named — emitting it per site made the reference app's home page 215 KB of the
78. // same code over and over.
79. let wi = 0
80. for (f of fns) {
81. wi = wi + 1
82. let name = 'w' + wi
83. src = src + 'var ' + name + '=' + f.src + ';'
84. for (site of f.sites) { src = src + f.slot + '[' + str(site) + ']=' + name + ';' }
85. }
86. let paints = []
87. collectPaints(&paints, roots)
88. for (e of paints) { src = src + 'P[' + str(e.site) + ']={p:' + e.paint + ',r:' + e.row + '};' }
89. src = src + 'C[' + str(key) + ']={v:' + root + ',b:B,t:T,e:E,f:F,p:P'
90. // THE ANSWERS A LOOKUP STILL NEEDS, and only those. A local event's write set stands
91. // at its own listener and a region's names at its own region — written into the
92. // call. These three are asked for by NAME at run time and cannot be: an inbound
93. // frame names its event, a routine handed down names the member that holds it, and
94. // a write set names the derivations that follow it.
95. src = src + ',ev:' + eventMap() + ',mw:' + memberMap() + ',dv:' + derivList() + '};'
96. return src + '})();' + newline
97. }
99. tbl = null
100. regions = {}
102. // what a DECLARED handler writes, by event: one entry per event name, unioned
103. eventMap() {
104. let byEvent = {}
105. for (h of tbl.handlers) {
106. if (!h.nested) {
107. let have = byEvent[h.event] == null ? [] : byEvent[h.event]
108. for (w of closeWrites(tbl, h.writes, h.reads)) { if (!have.includes(w)) { have.push(w) } }
109. byEvent[h.event] = have
110. }
111. }
112. return mapOf(byEvent)
113. }
115. // A MEMBER HOLDING A ROUTINE: what calling it writes is what its initializer writes
116. memberMap() {
117. let byName = {}
118. for (m of tbl.members) {
119. if (m.nodes != null) { byName[m.name] = memberNames(m.nodes.writes) }
120. }
121. return mapOf(byName)
122. }
124. // EVERY INITIALIZER, IN DECLARATION ORDER, with the members it reads — the whole of
125. // what a derivation needs; the class carries the computation itself as `__derive__`
126. derivList() {
127. let src = '['
128. let first = true
129. for (d of tbl.derivations) {
130. if (!first) { src = src + ',' }
131. first = false
132. src = src + '{name:' + str(d.name) + ',site:' + str(d.site) + ',reads:' + list(memberNames(d.reads)) + '}'
133. }
134. return src + ']'
135. }
137. mapOf(byName) {
138. let src = '{'
139. let first = true
140. for (k of byName.keys()) {
141. if (!first) { src = src + ',' }
142. first = false
143. src = src + str(k) + ':' + list(byName[k])
144. }
145. return src + '}'
146. }
148. // the write set and the read set of the handler at this site, closed over the methods
149. // it calls and the handlers it emits to — computed here, written into the listener
150. handlerSets(site) {
151. for (h of tbl.handlers) {
152. if (h.nested && h.site == site) {
153. return list(closeWrites(tbl, h.writes, h.reads)) + ',' + list(closeReads(tbl, h.reads))
154. }
155. }
156. return '[],[]'
157. }
159. regionNamesAt(site) {
160. let names = regions[site]
161. return list(names == null ? [] : names)
162. }
164. fns = []
166. // ---- the walk, unrolled ------------------------------------------------------------
167. // `top` marks the View's own root list: an element there is a COMPOSITION ROOT — a
168. // reference above may have overwritten some of its events and put classes on it, which
169. // is what `opt` carries (the old hl:web's rootOverwrites and withRootClasses).
170. walk(key, nodes) {
171. return plain(key, nodes)
172. }
174. // a list's walk
175. plain(key, nodes) {
176. let body = ''
177. for (n of nodes) { body = body + node(key, n, false, false) }
178. return 'async function(c,m,o,host,i,rows,rk,fill,cr,opt){let inst=m.instance;let r=rows;' + body + 'return i;}'
179. }
181. // the View's own root list, whose elements are composition roots
182. walkTop(key, nodes) {
183. let body = ''
184. for (n of nodes) { body = body + node(key, n, true, false) }
185. return 'async function(c,m,o,host,i,rows,rk,fill,cr,opt){let inst=m.instance;let r=rows;' + body + 'return i;}'
186. }
188. // a sub-walk, registered under its own site so the runtime can reach it by name
189. // A SUB-WALK IS WRITTEN ONCE, however often the compile reaches its list.
190. sub(key, nodes, slot, site) {
191. if (done[slot + ' ' + site] != null) { return null }
192. done[slot + ' ' + site] = true
193. fns.push({ slot = slot; sites = [site]; src = walk(key, nodes); })
194. return null
195. }
197. done = {}
199. node(key, n, top, filterOns) {
200. if (n.k == 'el') { return elNode(key, n, top) }
201. if (n.k == 'text') { return 'if(cr){host.appendChild(document.createTextNode(' + str(n.text) + '));}else{await c.leafAt(host,false,i,null,' + str(n.text) + ');}' }
202. if (n.k == 'on') {
203. // A REFERENCE ABOVE MAY HAVE OVERWRITTEN THIS EVENT on the composition root:
204. // the root's own handler for it is dropped and the reference's stands instead
205. // (the old hl:web's withoutOns, which applies to the root element's direct children).
206. let guard = filterOns ? 'if(!(opt&&opt.over&&opt.over.indexOf(' + str(n.event) + ')>=0)){' : '{'
207. return guard + 'await c.onAt(m,host,' + str(n.event) + ',' + str(n.site) + ',rows,' + handlerSets(n.site) + ');}'
208. }
209. if (n.k == 'member' && n.name == 'slot') {
210. // the SHELL's slot is where the route component hangs; a child's slot is the
211. // fragment its host wrote, and the host's frame builds it
212. return 'if(m.isShell){i=await c.slotShell(m,host,i,cr);}else if(fill!=null){i=await c.slotFill(m,o,host,i,fill,cr);}'
213. }
214. // A TEXT LEAF STANDING IN A LIST — an `if` branch, a `for` body — beside elements or
215. // alone: its own text node, and a site of the member it reads (or of the row it
216. // stands in), painted by rewriting that node.
217. if (n.k == 'member' || n.k == 'field') {
218. let names = (n.name == 'Style' || rowVars.includes(n.name)) ? [] : [n.name]
219. return 'await c.textAt(m,host,cr,function(inst,r){return ' + textRead(n) + ';},' + list(names) + ',rows,rk);'
220. }
221. if (n.k == 'for') {
222. // THE ROW VARIABLE IS IN SCOPE INSIDE THE BODY, and a read of it is the ROW's,
223. // not a member of the instance — the language resolves it that way and the site
224. // sets must say the same, or a member of the same name would paint the row.
225. rowVars.push(n.row)
226. sub(key, n.body, 'B', n.site)
227. rowVars.pop()
228. return 'i=await c.forAt(m,o,host,i,' + str(n.site) + ',' + str(n.row) + ',function(inst,r){return ' + rawRead(n.list) + ';},rows,rk,fill,cr,' + regionNamesAt(n.site) + ');'
229. }
230. if (n.k == 'if') {
231. sub(key, n.then, 'T', n.site)
232. sub(key, n.other, 'E', n.site)
233. return 'i=await c.ifAt(m,o,host,i,' + str(n.site) + ',function(inst,r){return ' + rawRead(n.cond) + ';},rows,rk,fill,cr,' + regionNamesAt(n.site) + ');'
234. }
235. if (n.k == 'component') {
236. if (n.fill != null && n.fill.length > 0) { sub(key, n.fill, 'F', n.site) }
237. return 'i=await c.kidAt(m,host,i,' + kidSpec(n) + ',rows,rk,fill,cr,opt);'
238. }
239. return ''
240. }
242. // ---- an element --------------------------------------------------------------------
243. elNode(key, n, top) {
244. let src = '{let el=A(cr,host,i,' + str(n.tag) + ');if(!cr){i=i+1;}'
245. src = src + 'if(el==null){await c.acqFail(' + str(n.tag) + ',host);}else{'
246. // the attributes, on the walk that BUILDS the element (a claim takes the server's)
247. src = src + 'if(cr){' + createAttrs(n) + (top ? 'await c.rootClasses(el,opt);' : '') + 'host.appendChild(el);}'
248. src = src + 'el.__hlRows=rows;el.__hlSite=' + str(n.site) + ';el.__hlKey=' + str(key) + ';'
249. // the element's own named entries, for the literal a handler on it fires
250. src = src + 'el.__hlLit=function(inst,r){return ' + litNamed(n) + ';};'
251. let names = siteNames(n)
252. let valueMember = 'null'
253. for (a of n.attrs) { if (a.member != null && a.name == 'value') { valueMember = str(a.member) } }
254. let sited = ''
255. if (names.length > 0 || valueMember != 'null') {
256. sited = 'await c.siteAt(m,el,' + list(names) + ',' + str(n.site) + ',' + valueMember + ',' + (n.tag == 'select' ? 'true' : 'false') + ',rows);'
257. }
258. let kids = ''
259. // AN ELEMENT THAT HOLDS ONLY TEXT is painted whole (`textContent`, see the paints):
260. // built, it gets that text as one node; claimed, the server's is taken as it stands
261. let whole = textOf(n)
262. if (whole != null) {
263. kids = 'if(cr){host.appendChild(document.createTextNode(' + whole + '));}'
264. for (c of n.children) { if (c.k == 'on') { kids = kids + node(key, c, false, top) } }
265. }
266. else if (mixed(n)) { kids = mixedKids(key, n, top) }
267. else { for (c of n.children) { kids = kids + node(key, c, false, top) } }
268. let inner = '{let host=el;let i=0;' + kids + '}'
269. // A SELECT IS SITED AFTER ITS OPTIONS: the member decides which option stands, and
270. // the read-back that `siteAt` does reports nothing before they exist.
271. if (n.tag == 'select') { src = src + inner + 'if(cr){await c.applySelectAt(m,el,' + selectValue(n) + ');}' + sited }
272. else { src = src + sited + inner }
273. return src + '}}'
274. }
276. // A TEXT LEAF BESIDE AN ELEMENT OR A REGION (ticket #86 follow-up): `td { d.n if (…) {…} }`
277. // cannot be painted through `textContent`, which would wipe the branch. Each RUN of
278. // adjacent leaves is one text node, held on the element (`__hlLeaves`, by the run's
279. // index) where the walk builds or claims it, and the paints rewrite that node alone.
280. mixed(n) {
281. if (textOf(n) != null) { return false }
282. for (c of n.children) { if ((c.k == 'member' || c.k == 'field') && c.name != 'slot') { return true } }
283. return false
284. }
286. isLeaf(c) { return c.k == 'text' || ((c.k == 'member' || c.k == 'field') && c.name != 'slot') }
288. // the runs of adjacent leaves, in order; an `on` renders nothing and splits none
289. runsOf(n) {
290. let out = []
291. let run = []
292. for (c of n.children) {
293. if (isLeaf(c)) { run.push(c) }
294. else if (c.k != 'on') {
295. if (run.length > 0) { out.push(run) }
296. run = []
297. }
298. }
299. if (run.length > 0) { out.push(run) }
300. return out
301. }
303. runText(run) {
304. let src = '""'
305. for (c of run) { src = src + '+(' + (c.k == 'text' ? str(c.text) : textRead(c)) + ')' }
306. return src
307. }
309. runFeeds(run) {
310. for (c of run) { if (c.k != 'text') { return true } }
311. return false
312. }
314. mixedKids(key, n, top) {
315. let kids = ''
316. let run = []
317. let k = 0
318. for (c of n.children) {
319. if (isLeaf(c)) { run.push(c) }
320. else {
321. if (c.k != 'on' && run.length > 0) { kids = kids + leafRun(run, k) k = k + 1 run = [] }
322. kids = kids + node(key, c, false, top)
323. }
324. }
325. if (run.length > 0) { kids = kids + leafRun(run, k) }
326. return kids
327. }
329. // EVERY CALL INTO THE CLIENT IS AWAITED: its methods are async in the browser, and one
330. // not awaited runs its DOM work after the walk has gone on — a built leaf then lands
331. // after the elements that follow it (ticket #104).
332. leafRun(run, k) {
333. if (!runFeeds(run)) { return 'if(cr){host.appendChild(document.createTextNode(' + runText(run) + '));}else{await c.leafAt(host,false,i,null,' + runText(run) + ');}' }
334. return 'await c.leafAt(host,cr,i,' + k + ',' + runText(run) + ');'
335. }
337. // the attributes an element is BUILT with — a bound one written in, a literal one as it
338. // stands. `value` is a property once the page is live and an attribute as the control's
339. // default; a textarea has no value attribute at all and a select's value is an option.
340. createAttrs(n) {
341. let src = ''
342. for (a of n.attrs) {
343. if (isBool(a)) {
344. src = src + '{' + boolWrite(a, rawRead(a.member != null ? { k = 'member'; name = a.member; } : a.ref)) + '}'
345. } else {
346. let rd = a.member != null ? readOf({ k = 'member'; name = a.member; }) : (a.ref != null ? readOf(a.ref) : str(a.text))
347. src = src + '{let v=' + rd + ';'
348. if (a.extra != null) { src = src + 'v=v+" "+' + str(a.extra) + ';' }
349. if (n.tag == 'select' && a.name == 'value') { src = src + '}' }
350. else if (a.name == 'value') {
351. src = src + 'if(el.value!=null){el.value=v;' + (n.tag == 'textarea' ? '' : 'el.setAttribute("value",v);') + '}else{el.setAttribute("value",v);}}'
352. } else { src = src + 'el.setAttribute(' + str(a.name) + ',v);}' }
353. }
354. }
355. if (boundValue(n)) { src = src + 'el.setAttribute("autocomplete","off");' }
356. return src
357. }
359. // a BOUND boolean attribute — a literal one was decided at build (WebFramework `element`)
360. isBool(a) {
361. return (a.member != null || a.ref != null) && v.isBoolAttr(a.name)
362. }
364. // A BOUND BOOLEAN ATTRIBUTE, WRITTEN (ticket #33): set when the value is on, REMOVED when
365. // it is off — the markup's rule (view.boolAttrs) — and the DOM property with it, because
366. // once the page is live `checked` is the property and the attribute only its default.
367. boolWrite(a, raw) {
368. let prop = a.name == 'readonly' ? 'readOnly' : a.name
369. return 'let on=!!' + raw + ';if(on){el.setAttribute(' + str(a.name) + ',"");}else if(el.removeAttribute){el.removeAttribute(' + str(a.name) + ');}if(' + str(prop) + ' in el&&el[' + str(prop) + ']!==on){el[' + str(prop) + ']=on;}'
370. }
372. // view.hl's `boundValue`, to the letter: a FORM CONTROL whose `value` reads a member or
373. // a field, and not one the author gave an `autocomplete` of its own
374. boundValue(n) {
375. if (n.tag != 'input' && n.tag != 'textarea' && n.tag != 'select') { return false }
376. let bound = false
377. for (a of n.attrs) {
378. if (a.name == 'autocomplete') { return false }
379. if (a.name == 'value' && (a.member != null || a.ref != null)) { bound = true }
380. }
381. return bound
382. }
384. selectValue(n) {
385. for (a of n.attrs) {
386. if (a.name == 'value') {
387. if (a.member != null) { return readOf({ k = 'member'; name = a.member; }) }
388. if (a.ref != null) { return readOf(a.ref) }
389. return str(a.text)
390. }
391. }
392. return 'null'
393. }
395. // the element's own entries as the literal sees them — its attributes by name, then the
396. // `for` row variables in scope (the row rides on the value)
397. litNamed(n) {
398. let src = '{'
399. let first = true
400. for (a of n.attrs) {
401. if (!first) { src = src + ',' }
402. first = false
403. let v = a.member != null ? rawRead({ k = 'member'; name = a.member; }) : (a.ref != null ? rawRead(a.ref) : str(a.text))
404. src = src + str(a.name) + ':' + v
405. }
406. return src + '}'
407. }
409. // the reference's own description, written at its use site: what it binds, what it
410. // overwrites, the classes the host's `#Child` rule puts on it
411. kidSpec(n) {
412. let src = '{key:' + str(n.key) + ',kid:' + str(kidKeyOf(n)) + ',site:' + str(n.site) + ',fill:' + ((n.fill != null && n.fill.length > 0) ? 'true' : 'false')
413. src = src + ',bindings:['
414. let first = true
415. for (b of n.bindings) {
416. if (!first) { src = src + ',' }
417. first = false
418. src = src + '{name:' + str(b.name) + ',member:' + (b.member == null ? 'null' : str(b.member))
419. src = src + ',ref:' + (b.ref == null ? 'null' : 'function(inst,r){return ' + rawRead(b.ref) + ';}')
420. src = src + ',refName:' + (b.ref == null ? 'null' : str(b.ref.name))
421. src = src + ',text:' + (b.text == null ? 'null' : 'true') + ',value:' + (b.text == null ? 'null' : refLiteral(b)) + '}'
422. }
423. src = src + '],ons:['
424. first = true
425. for (o of n.ons) {
426. if (!first) { src = src + ',' }
427. first = false
428. src = src + '{event:' + str(o.event) + ',site:' + str(o.site) + ',sets:[' + handlerSets(o.site) + ']}'
429. }
430. src = src + '],classes:' + list(n.classes == null ? [] : n.classes) + '}'
431. return src
432. }
434. // view.hl's kidKey: the reference's path, joined — the key the server mounted it under
435. kidKeyOf(n) {
436. let out = ''
437. for (p of n.path) { out = out + '/' + p }
438. return out
439. }
441. // the value a literal binding carries — view.refValue, folded at compile time
442. refLiteral(b) {
443. if (b.kind == 'folded') { return jsValue(b.value) }
444. if (b.kind == 'number') { return '' + b.text }
445. if (b.kind == 'boolean') { return b.text == 'true' ? 'true' : 'false' }
446. if (b.kind == 'null_literal') { return 'null' }
447. return str(b.text)
448. }
450. jsValue(v) {
451. if (v == null) { return 'null' }
452. if (hlTypeName(v) == 'String') { return str(v) }
453. if (hlTypeName(v) == 'Boolean') { return v ? 'true' : 'false' }
454. if (hlTypeName(v) == 'Number') { return '' + v }
455. return JSON.stringify(v)
456. }
458. // ---- the site set: what this element SHOWS ------------------------------------------
459. // The old hl:web asked the module's table which members the element at this site reads. The
460. // answer is a fact about the View, so it is written in: the members its bound
461. // attributes and its text leaves name. `Style` is folded into a class name at build and
462. // the shell's `slot` is swapped by navigation — neither is ever painted, and neither is
463. // a member read that reaches here (a `for` row variable resolves to its row).
464. siteNames(n) {
465. let out = []
466. for (a of n.attrs) {
467. if (a.member != null && a.member != 'Style' && !rowVars.includes(a.member) && !out.includes(a.member)) { out.push(a.member) }
468. // A FIELD OF A MEMBER (`value = f.title`, ticket #93) is a read of the member:
469. // a write to `f.title`, or a new `f`, moves `f`, and this element repaints
470. if (a.ref != null && a.ref.name != 'Style' && !rowVars.includes(a.ref.name) && !out.includes(a.ref.name)) { out.push(a.ref.name) }
471. }
472. for (c of n.children) {
473. if ((c.k == 'member' || c.k == 'field') && c.name != 'slot' && c.name != 'Style' && !rowVars.includes(c.name)) {
474. if (!out.includes(c.name)) { out.push(c.name) }
475. }
476. }
477. return out
478. }
480. rowVars = []
482. // ---- the paints ---------------------------------------------------------------------
483. collectPaints(&out, nodes) {
484. for (n of nodes) {
485. if (n.k == 'el') {
486. let paint = paintFn(n)
487. let row = rowFn(n)
488. if (paint != null || row != 'null') {
489. out.push({ site = n.site; paint = paint == null ? 'null' : paint; row = row; })
490. }
491. collectPaints(&out, n.children)
492. } else if (n.k == 'for') { collectPaints(&out, n.body) }
493. else if (n.k == 'if') { collectPaints(&out, n.then) collectPaints(&out, n.other) }
494. else if (n.k == 'component') { if (n.fill != null) { collectPaints(&out, n.fill) } }
495. }
496. return null
497. }
499. // `paint(&m, s, name)`, compiled: the bound attributes under the member each reads, and
500. // the text where the member that moved stands among the leaves.
501. paintFn(n) {
502. let body = ''
503. for (a of n.attrs) {
504. if (a.member != null) {
505. body = body + 'if(n===' + str(a.member) + '){' + attrWrite(n, a, readOf({ k = 'member'; name = a.member; })) + '}'
506. } else if (a.ref != null) {
507. // a field of a member paints when the MEMBER moves (ticket #93)
508. body = body + 'if(n===' + str(a.ref.name) + '){' + attrWrite(n, a, readOf(a.ref)) + '}'
509. }
510. }
511. let text = textOf(n)
512. if (text != null) {
513. let guard = ''
514. for (c of n.children) {
515. if ((c.k == 'member' || c.k == 'field') && c.name != 'slot') {
516. if (guard != '') { guard = guard + '||' }
517. guard = guard + 'n===' + str(c.name)
518. }
519. }
520. if (guard != '') { body = body + 'if(' + guard + '){el.textContent=' + text + ';}' }
521. } else if (mixed(n)) {
522. let k = 0
523. for (run of runsOf(n)) {
524. let guard = ''
525. for (c of run) {
526. if (c.k != 'text') {
527. if (guard != '') { guard = guard + '||' }
528. guard = guard + 'n===' + str(c.name)
529. }
530. }
531. if (guard != '') { body = body + 'if((' + guard + ')&&el.__hlLeaves&&el.__hlLeaves[' + k + ']){el.__hlLeaves[' + k + '].data=' + runText(run) + ';}' }
532. k = k + 1
533. }
534. }
535. if (body == '') { return null }
536. return 'function(el,inst,r,n){' + body + '}'
537. }
539. // `rowPaint(&m, el)`, compiled: every bound spot, written only where the DOM does not
540. // already hold it — which is why a push into 2000 rows costs the 1999 nothing.
541. rowFn(n) {
542. let body = ''
543. for (a of n.attrs) {
544. if (isBool(a)) {
545. body = body + '{' + boolWrite(a, rawRead(a.member != null ? { k = 'member'; name = a.member; } : a.ref)) + '}'
546. } else if (a.member != null || a.ref != null) {
547. let one = 'let v=' + readOf(a.member != null ? { k = 'member'; name = a.member; } : a.ref) + ';'
548. if (a.extra != null) { one = one + 'v=v+" "+' + str(a.extra) + ';' }
549. if (n.tag == 'select' && a.name == 'value') { one = one + 'if(el.value!==v){el.value=v;}' }
550. else {
551. one = one + 'if(el.getAttribute(' + str(a.name) + ')!==v){el.setAttribute(' + str(a.name) + ',v);}'
552. if (a.name == 'value') { one = one + 'if(el.value!=null&&el.value!==v){el.value=v;}' }
553. }
554. body = body + '{' + one + '}'
555. }
556. }
557. let text = textOf(n)
558. let feeds = false
559. for (c of n.children) { if ((c.k == 'member' || c.k == 'field') && c.name != 'slot') { feeds = true } }
560. if (text != null && feeds) { body = body + '{let t=' + text + ';if(el.textContent!==t){el.textContent=t;}}' }
561. if (text == null && feeds) {
562. let k = 0
563. for (run of runsOf(n)) {
564. if (runFeeds(run)) { body = body + '{let x=el.__hlLeaves&&el.__hlLeaves[' + k + '];let t=' + runText(run) + ';if(x&&x.data!==t){x.data=t;}}' }
565. k = k + 1
566. }
567. }
568. if (body == '') { return 'null' }
569. return 'function(el,inst,r){' + body + '}'
570. }
572. attrWrite(n, a, v) {
573. if (isBool(a)) { return boolWrite(a, rawRead(a.member != null ? { k = 'member'; name = a.member; } : a.ref)) }
574. let src = 'let v=' + v + ';'
575. if (a.extra != null) { src = src + 'v=v+" "+' + str(a.extra) + ';' }
576. if (n.tag == 'select' && a.name == 'value') { return src + 'el.value=v;' }
577. src = src + 'el.setAttribute(' + str(a.name) + ',v);'
578. if (a.name == 'value') { src = src + 'if(el.value!=null){el.value=v;}' }
579. return src
580. }
582. textOf(n) {
583. let parts = []
584. let content = 0
585. let feeds = false
586. for (c of n.children) {
587. if (c.k != 'on') {
588. content = content + 1
589. if (c.k == 'text') { parts.push(str(c.text)) }
590. else if ((c.k == 'member' || c.k == 'field') && c.name != 'slot') { parts.push(textRead(c)) feeds = true }
591. }
592. }
593. if (!feeds) { return null }
594. if (parts.length != content) { return null }
595. let src = '""'
596. for (p of parts) { src = src + '+(' + p + ')' }
597. return src
598. }
600. // ---- a read, written in ---------------------------------------------------------------
601. // `view.value`'s own rule as an expression: a `for` row variable in scope wins over a
602. // member of the same name, and a field path walks into it. `readOf` answers the STRING
603. // the DOM takes; `rawRead` the value itself (a binding, a list, a condition).
604. readOf(node) { return '(""+' + rawRead(node) + ')' }
606. // A READ SHOWN AS TEXT: null is no text, as the server writes it (view.hl `escape`)
607. textRead(node) { return 'S(' + rawRead(node) + ')' }
609. rawRead(node) {
610. if (node == null) { return 'null' }
611. if (node.k == 'text') { return str(node.text) }
612. if (node.k != 'field') { return 'RV(r,inst,' + str(node.name) + ')' }
613. return 'RF(r,inst,' + str(node.name) + ',' + list(node.path) + ')'
614. }
616. list(names) {
617. let src = '['
618. let first = true
619. for (n of names) {
620. if (!first) { src = src + ',' }
621. first = false
622. src = src + str(n)
623. }
624. return src + ']'
625. }
627. // a JavaScript string literal — JSON's escaping is a subset of JavaScript's, so a
628. // source text's quotes, newlines and backslashes survive into the statement unchanged
629. str(s) {
630. if (s == null) { return '""' }
631. return JSON.stringify('' + s)
632. }
634. // ---- WHAT THE LANGUAGE SAYS ABOUT THIS FILE, read HERE and written into the code ----
635. // The old hl:web shipped the language's answers to the browser as data: `hlJs` writes each file's
636. // members, handlers and methods — every node of every initializer, with the names it
637. // reads — into the module, and the client reduces that table on every boot. The answers
638. // are facts about the source, so this file asks for them once, at compile time, and
639. // writes the RESULT into the statements: a handler's write set stands at the listener
640. // that needs it, a region's names at the region, the derivations as a list of what to
641. // re-run. The module carries no table at all (WebFramework `module` drops the one the
642. // emitter writes).
643. //
644. // The reflection is the framework's own analysis generation — the same `gen` the View
645. // trees come from. Nothing starts a second one: a handle is only valid inside the
646. // generation that made it.
647. tableOf(gen, key) {
648. let members = []
649. let derivations = []
650. let handlers = []
651. let methods = []
652. for (m of hlMembers(gen, key)) {
653. let entry = { name = m.name; nodes = null; }
654. if (m.hasValue) {
655. let n = syntaxTree(gen, key, m.node)
656. entry.nodes = n
657. derivations.push({ name = m.name; site = n.site; reads = n.reads; })
658. nestedHandlers(&handlers, n)
659. }
660. members.push(entry)
661. }
662. for (h of hlEvents(gen, key).handles) {
663. let n = syntaxTree(gen, key, h.node)
664. handlers.push({ event = h.event; site = n.site; reads = n.reads; writes = n.writes; nested = false; })
665. }
666. for (mm of hlMethods(gen, key)) {
667. if (!mm.inlineHandler) {
668. let n = syntaxTree(gen, key, mm.node)
669. methods.push({ name = mm.name; reads = n.reads; writes = n.writes; })
670. }
671. }
672. return { members = members; derivations = derivations; handlers = handlers; methods = methods; }
673. }
675. // A NESTED `on` IS A DOM HANDLER, filed under its own site — the id the View node
676. // carries. Its body is not the literal's syntax, so the node answers for it and the
677. // walk stops there.
678. nestedHandlers(&into, n) {
679. if (n == null) { return null }
680. if (n.tag == 'on_statement') {
681. into.push({ event = n.event; site = n.site; reads = n.reads; writes = n.writes; nested = true; })
682. return null
683. }
684. for (c of [n.value, n.list, n.body, n.condition, n.consequent, n.alternate, n.object, n.property, n.callee, n.left, n.right, n.operand]) {
685. if (c != null) { nestedHandlers(&into, c) }
686. }
687. for (l of [n.entries, n.args, n.elements]) {
688. if (l != null) { for (c of l) { nestedHandlers(&into, c) } }
689. }
690. return null
691. }
693. shortSite(site) {
694. if (site == null) { return null }
695. let at = site.indexOf(':')
696. if (at < 0) { return site }
697. let path = site.slice(0, at)
698. let cut = path.lastIndexOf('/')
699. if (cut < 0) { return site }
700. return path.slice(cut + 1) + site.slice(at)
701. }
703. // the syntax of one node, recursively — hl:core/AST's `tree`, read off the framework's
704. // own generation instead of starting one of its own
705. syntaxTree(gen, key, node) {
706. let n = hlSyntax(gen, key, node)
707. if (n == null) { return null }
708. // A SITE IS NAMED BY THE FILE'S BASE NAME. The reflection answers with the project
709. // key ('components/sort_list.hl:77:26'); the View tree, the emitter's own
710. // `__derive__` branches and every site this framework writes use the base name
711. // ('sort_list.hl:77:26'). One spelling, or a lookup by site finds nothing.
712. let out = { tag = n.tag; site = shortSite(n.site); reads = n.reads; writes = n.writes; }
713. if (n.tag == 'object_expression') {
714. let kids = []
715. for (h of n.entries) { kids.push(syntaxTree(gen, key, h)) }
716. out.entries = kids
717. } else if (n.tag == 'object_property') {
718. out.key = n.key
719. out.value = syntaxTree(gen, key, n.value)
720. } else if (n.tag == 'view_for') {
721. out.list = syntaxTree(gen, key, n.list)
722. out.body = syntaxTree(gen, key, n.body)
723. } else if (n.tag == 'view_if') {
724. out.condition = syntaxTree(gen, key, n.condition)
725. out.consequent = syntaxTree(gen, key, n.consequent)
726. out.alternate = syntaxTree(gen, key, n.alternate)
727. } else if (n.tag == 'on_statement') {
728. out.event = n.event
729. } else if (n.tag == 'member_expression') {
730. out.object = syntaxTree(gen, key, n.object)
731. out.property = syntaxTree(gen, key, n.property)
732. } else if (n.tag == 'call_expression') {
733. out.callee = syntaxTree(gen, key, n.callee)
734. let args = []
735. for (h of n.args) { args.push(syntaxTree(gen, key, h)) }
736. out.args = args
737. } else if (n.tag == 'binary_expression') {
738. out.left = syntaxTree(gen, key, n.left)
739. out.right = syntaxTree(gen, key, n.right)
740. } else if (n.tag == 'unary_expression') {
741. out.operand = syntaxTree(gen, key, n.operand)
742. } else if (n.tag == 'conditional_expression') {
743. out.condition = syntaxTree(gen, key, n.condition)
744. out.consequent = syntaxTree(gen, key, n.consequent)
745. out.alternate = syntaxTree(gen, key, n.alternate)
746. } else if (n.tag == 'array_expression') {
747. let els = []
748. for (h of n.elements) { els.push(syntaxTree(gen, key, h)) }
749. out.elements = els
750. }
751. return out
752. }
754. // ---- the reductions the browser used to make on every boot --------------------------
755. // A `for`'s names are what its list reads, an `if`'s what its condition reads — filed
756. // under the region's own site.
757. regionIndex(t) {
758. let idx = {}
759. for (m of t.members) { if (m.nodes != null) { indexRegions(&idx, m.nodes) } }
760. return idx
761. }
763. indexRegions(&idx, n) {
764. if (n == null) { return null }
765. if (n.tag == 'view_for') {
766. idx[n.site] = memberNames(nodeReads(n.list))
767. indexRegions(&idx, n.body)
768. return null
769. }
770. if (n.tag == 'view_if') {
771. idx[n.site] = memberNames(nodeReads(n.condition))
772. indexRegions(&idx, n.consequent)
773. indexRegions(&idx, n.alternate)
774. return null
775. }
776. if (n.tag == 'on_statement') { return null }
777. for (c of [n.value, n.list, n.body, n.condition, n.consequent, n.alternate, n.object, n.property, n.callee, n.left, n.right, n.operand]) {
778. if (c != null) { indexRegions(&idx, c) }
779. }
780. for (l of [n.entries, n.args, n.elements]) {
781. if (l != null) { for (c of l) { indexRegions(&idx, c) } }
782. }
783. return null
784. }
786. // the member reads of a read list — the language resolved every name, so this is a
787. // filter and not a second resolution
788. memberNames(reads) {
789. let out = []
790. if (reads == null) { return out }
791. for (r of reads) {
792. if (r.kind == 'member' && r.isStatic != true && !out.includes(r.name)) { out.push(r.name) }
793. }
794. return out
795. }
797. nodeReads(n) {
798. if (n == null) { return [] }
799. if (n.reads != null) { return n.reads }
800. let out = []
801. for (c of [n.value, n.list, n.body, n.condition, n.consequent, n.alternate, n.object, n.property, n.callee, n.left, n.right, n.operand]) {
802. if (c != null) { for (r of nodeReads(c)) { out.push(r) } }
803. }
804. for (l of [n.entries, n.args, n.elements]) {
805. if (l != null) { for (c of l) { for (r of nodeReads(c)) { out.push(r) } } }
806. }
807. return out
808. }
810. // A ROUTINE'S WRITES, PLUS THE WRITES OF EVERYTHING IT REACHES — the method it calls
811. // and the handler it emits to, transitively. Both are READS the language resolved, so
812. // this is a walk of its answer and never a guess.
813. closeWrites(t, writes, reads) {
814. let out = memberNames(writes)
815. let queue = []
816. reached(&queue, reads)
817. let seen = {}
818. while (queue.length > 0) {
819. let at = queue.shift()
820. if (seen[at] == null) {
821. seen[at] = true
822. let sp = at.indexOf(' ')
823. let kind = at.slice(0, sp)
824. let name = at.slice(sp + 1)
825. for (mm of t.methods) {
826. if (kind == 'method' && mm.name == name) {
827. for (w of memberNames(mm.writes)) { if (!out.includes(w)) { out.push(w) } }
828. reached(&queue, mm.reads)
829. }
830. }
831. for (h of t.handlers) {
832. if (kind == 'handler' && !h.nested && h.event == name) {
833. for (w of memberNames(h.writes)) { if (!out.includes(w)) { out.push(w) } }
834. reached(&queue, h.reads)
835. }
836. }
837. for (mb of t.members) {
838. if (kind == 'member' && mb.name == name && mb.nodes != null) {
839. for (w of memberNames(mb.nodes.writes)) { if (!out.includes(w)) { out.push(w) } }
840. reached(&queue, nodeReads(mb.nodes))
841. }
842. }
843. }
844. }
845. return out
846. }
848. // the mirror: a handler's reads plus the reads of everything it reaches — the
849. // candidates for a routine a host handed down, whose writes only the host's table names
850. closeReads(t, reads) {
851. let out = memberNames(reads)
852. let queue = []
853. reached(&queue, reads)
854. let seen = {}
855. while (queue.length > 0) {
856. let at = queue.shift()
857. if (seen[at] == null) {
858. seen[at] = true
859. let sp = at.indexOf(' ')
860. let kind = at.slice(0, sp)
861. let name = at.slice(sp + 1)
862. for (mm of t.methods) {
863. if (kind == 'method' && mm.name == name) {
864. for (r of memberNames(mm.reads)) { if (!out.includes(r)) { out.push(r) } }
865. reached(&queue, mm.reads)
866. }
867. }
868. for (h of t.handlers) {
869. if (kind == 'handler' && !h.nested && h.event == name) {
870. for (r of memberNames(h.reads)) { if (!out.includes(r)) { out.push(r) } }
871. reached(&queue, h.reads)
872. }
873. }
874. for (mb of t.members) {
875. if (kind == 'member' && mb.name == name && mb.nodes != null) {
876. for (r of memberNames(nodeReads(mb.nodes))) { if (!out.includes(r)) { out.push(r) } }
877. reached(&queue, nodeReads(mb.nodes))
878. }
879. }
880. }
881. }
882. return out
883. }
885. reached(&queue, reads) {
886. if (reads == null) { return null }
887. for (r of reads) {
888. if (r.kind == 'method' || r.kind == 'handler' || (r.kind == 'member' && r.isStatic != true)) { queue.push(r.kind + ' ' + r.name) }
889. }
890. return null
891. }
893. // ---- THE SERVER RENDER, COMPILED --------------------------------------------------
894. // The old hl:web rendered a page by WALKING the View tree per request: for every node it asks
895. // what kind it is, for every element it builds the attribute string, and it decides the
896. // indentation of every line again, on every request, for every one of the 121 mounts a
897. // page may hold. Every one of those decisions is a fact about the View.
898. //
899. // So a component's render is compiled ONCE into a list of STEPS — constant text, and a
900. // read with its own closure — and a request is a concatenation. The structure (tags,
901. // static attributes, the readable form's line breaks, which element is a block) is
902. // decided at compile time; only the values are asked for per request.
903. //
904. // KEYED BY THE INDENT IT IS RENDERED AT, because that is the only thing about a
905. // component's HTML that its caller decides: the shell renders at one tab, the page at
906. // the depth the slot stands, a fill compactly (null). An app has a handful of those.
907. serverSteps(key, nodes, indent, classes, slotted) {
908. let ck = key + '|' + (indent == null ? '~' : indent) + '|' + joinList(classes) + '|' + (slotted ? '1' : '0')
909. if (steps[ck] == null) {
910. steps[ck] = blockSteps(classes == null || classes.length == 0 ? nodes : v.withRootClasses(nodes, classes), indent, slotted)
911. }
912. return steps[ck]
913. }
915. // A `slot` THE HOST FILLED COUNTS AS CONTENT, and an empty one does not — the one
916. // thing about a component's shape its caller decides, so it is part of the key.
917. staticVoid = [ 'area' 'base' 'br' 'col' 'embed' 'hr' 'img' 'input' 'link' 'meta' 'source' 'track' 'wbr' ]
918. staticVerbatim = [ 'textarea' 'pre' 'script' 'style' ]
920. blocky(n, slotted) {
921. if (staticVerbatim.includes(n.tag)) { return false }
922. if (n.children.length == 0) { return false }
923. for (c of n.children) {
924. if (c.k == 'text' || c.k == 'field') { return false }
925. if (c.k == 'member' && !(c.name == 'slot' && slotted)) { return false }
926. }
927. return true
928. }
930. steps = {}
931. v = new View
933. joinList(l) {
934. if (l == null) { return '' }
935. let out = ''
936. for (c of l) { out = out + ',' + c }
937. return out
938. }
940. // `render(nodes, …, indent)`: the readable form puts each element on its own line at
941. // `indent`, the compact one writes them end to end.
942. blockSteps(nodes, indent, slotted) {
943. let out = []
944. for (n of nodes) {
945. if (indent != null) {
946. if (n.k == 'el') { push(&out, { k = 's'; v = newline + indent; }) nodeSteps(&out, n, indent, slotted) }
947. else if (n.k == 'component') { nodeSteps(&out, n, indent, slotted) }
948. else if (n.k == 'for') { forSteps(&out, n, indent, slotted) }
949. else if (n.k == 'if') { ifSteps(&out, n, indent, slotted) }
950. else if (n.k == 'member' && n.name == 'slot') { push(&out, { k = 'slotline'; v = newline + indent; }) }
951. else if (n.k != 'on') { nodeSteps(&out, n, indent, slotted) }
952. } else {
953. nodeSteps(&out, n, null, slotted)
954. }
955. }
956. return out
957. }
959. forSteps(&out, n, indent, slotted) {
960. out.push({ k = 'for'; row = n.row; read = readFn(n.list); body = blockSteps(n.body, indent, slotted); })
961. return null
962. }
964. ifSteps(&out, n, indent, slotted) {
965. out.push({ k = 'if'; read = readFn(n.cond); then = blockSteps(n.then, indent, slotted); other = blockSteps(n.other, indent, slotted); })
966. return null
967. }
969. // one node's steps — `html(node, …)`, decided once
970. nodeSteps(&out, n, indent, slotted) {
971. if (n.k == 'text') { push(&out, { k = 's'; v = v.escape(n.text); }) return null }
972. if (n.k == 'on') { return null }
973. if (n.k == 'member' && n.name == 'slot') { out.push({ k = 'slot'; }) return null }
974. if (n.k == 'member' || n.k == 'field') { out.push({ k = 'r'; read = readFn(n); }) return null }
975. if (n.k == 'for') { forSteps(&out, n, indent, slotted) return null }
976. if (n.k == 'if') { ifSteps(&out, n, indent, slotted) return null }
977. if (n.k == 'component') {
978. out.push({ k = 'kid'; path = n.path; cls = n.cls; key = n.key; classes = n.classes; indent = indent;
979. fill = (n.fill == null || n.fill.length == 0) ? null : blockSteps(n.fill, null, slotted); })
980. return null
981. }
982. if (n.k == 'el') { elSteps(&out, n, indent, slotted) return null }
983. push(&out, { k = 's'; v = '<!-- ' + n.tag + ' not rendered yet -->'; })
984. return null
985. }
987. elSteps(&out, n, indent, slotted) {
988. let attrs = []
989. let valueRead = null // a textarea's value is its content
990. let selRead = null // a select's value selects an option
991. for (a of n.attrs) {
992. if (n.tag == 'textarea' && a.name == 'value') { valueRead = attrRead(a) }
993. else if (n.tag == 'select' && a.name == 'value') { selRead = attrRead(a) }
994. // a bound BOOLEAN attribute is its presence (ticket #33): ` checked=""` or nothing
995. else if ((a.member != null || a.ref != null) && v.isBoolAttr(a.name)) { attrs.push({ k = 'b'; name = a.name; read = attrRead(a); }) }
996. else if (a.member != null || a.ref != null) {
997. push(&attrs, { k = 's'; v = ' ' + a.name + '="'; })
998. attrs.push({ k = 'r'; read = attrRead(a); })
999. push(&attrs, { k = 's'; v = v.extraOf(a) + '"'; })
1000. } else {
1001. push(&attrs, { k = 's'; v = ' ' + a.name + '="' + v.escape(a.text) + '"'; })
1002. }
1003. }
1004. if (v.boundValue(n)) { push(&attrs, { k = 's'; v = ' autocomplete="off"'; }) }
1006. // the children, in the form this element takes: a block puts them one per line
1007. let kids = []
1008. if (indent != null && blocky(n, slotted)) {
1009. kids = blockSteps(n.children, indent + tab, slotted)
1010. push(&kids, { k = 's'; v = newline + indent; })
1011. } else {
1012. kids = blockSteps(n.children, null, slotted)
1013. }
1014. if (valueRead != null) { kids = [{ k = 'r'; read = valueRead; }] }
1016. // AN OPTION IS THE ONE ELEMENT WHOSE OWN TAG DEPENDS ON THE VALUE ABOVE IT: it
1017. // carries `selected` when its value is the select's. Everything else is settled.
1018. if (n.tag == 'option') {
1019. out.push({ k = 'opt'; attrs = attrs; body = kids; ov = optionRead(n); })
1020. return null
1021. }
1022. push(&out, { k = 's'; v = '<' + n.tag; })
1023. for (a of attrs) { push(&out, a) }
1024. if (staticVoid.includes(n.tag)) { push(&out, { k = 's'; v = '>'; }) return null }
1025. push(&out, { k = 's'; v = '>'; })
1026. // A SELECT HANDS ITS VALUE TO ITS OPTIONS, however deep they stand: its children
1027. // run under it, and it is the only element that changes anything for them.
1028. if (n.tag == 'select') { out.push({ k = 'sel'; read = selRead; body = kids; }) }
1029. else { for (kk of kids) { push(&out, kk) } }
1030. push(&out, { k = 's'; v = '</' + n.tag + '>'; })
1031. return null
1032. }
1034. // CONSTANT TEXT MERGES. Two literal steps in a row are one string decided at compile
1035. // time — which is what makes a request a concatenation of a handful of pieces instead
1036. // of one per node.
1037. push(&out, step) {
1038. if (step.k == 's' && out.length > 0 && out[out.length - 1].k == 's') {
1039. let last = out[out.length - 1]
1040. last.v = last.v + step.v
1041. out[out.length - 1] = last
1042. return null
1043. }
1044. out.push(step)
1045. return null
1046. }
1048. // ---- the reads, each with its own closure ------------------------------------------
1049. // `view.value`'s rule, split once: a `for` row variable in scope wins over a member of
1050. // the same name, and a field path walks into it. The closure holds the name — there is
1051. // no node to look at per request.
1052. readFn(node) {
1053. if (node == null) { return (inst, rows) => { return null } }
1054. if (node.k == 'text') { let t = v.literalValue(node.kind, node.text) return (inst, rows) => { return t } }
1055. let name = node.name
1056. if (node.k != 'field') {
1057. return (inst, rows) => { return rows[name] != null ? rows[name] : inst[name] }
1058. }
1059. let path = node.path
1060. return (inst, rows) => {
1061. let val = rows[name] != null ? rows[name] : inst[name]
1062. for (f of path) {
1063. if (val == null) { return null }
1064. val = val[f]
1065. }
1066. return val
1067. }
1068. }
1070. attrRead(a) {
1071. if (a.member != null) { return readFn({ k = 'member'; name = a.member; }) }
1072. if (a.ref != null) { return readFn(a.ref) }
1073. let t = a.text
1074. return (inst, rows) => { return t }
1075. }
1077. // an option's own value: its `value` attribute, or null when it has none (the browser
1078. // then reports its text, and the run compares against what it rendered)
1079. optionRead(n) {
1080. for (a of n.attrs) {
1081. if (a.name == 'value') { return attrRead(a) }
1082. }
1083. return null
1084. }
1086. // ---- the run: a concatenation ------------------------------------------------------
1087. // EVERY REGION IS WRITTEN BETWEEN TWO MARKS (tickets #103, #104): an `if` around the
1088. // branch that stands, a `for` around its rows and each row around its own nodes. The
1089. // client claims them as they are and builds the same ones, and a region's nodes are
1090. // exactly what stands between its two marks — nothing it holds has to be remembered
1091. // node by node, and text beside a region can never run into the region's text.
1092. markOpen = '<!--[-->'
1093. markClose = '<!--]-->'
1095. runSteps(list, &inst, &rows, &ctx) {
1096. let out = ''
1097. for (s of list) {
1098. if (s.k == 's') { out = out + s.v }
1099. else if (s.k == 'r') { let f = s.read out = out + v.escape(f(&inst, &rows)) }
1100. else if (s.k == 'b') { let f = s.read if (v.boolOn(f(&inst, &rows))) { out = out + ' ' + s.name + '=""' } }
1101. else if (s.k == 'slot') { if (ctx.slot != null) { out = out + ctx.slot } }
1102. else if (s.k == 'slotline') { if (ctx.slot != null) { out = out + s.v + ctx.slot } }
1103. else if (s.k == 'for') {
1104. let f = s.read
1105. let list2 = f(&inst, &rows)
1106. out = out + markOpen
1107. if (list2 != null) {
1108. let ri = 0
1109. for (entry of list2) {
1110. let inner = rows + {}
1111. inner[s.row] = entry
1112. let rc = v.rowCtx(&ctx, &entry, ri)
1113. out = out + markOpen + runSteps(s.body, &inst, &inner, &rc) + markClose
1114. ri = ri + 1
1115. }
1116. }
1117. out = out + markClose
1118. }
1119. else if (s.k == 'if') {
1120. let f = s.read
1121. if (f(&inst, &rows)) { out = out + markOpen + runSteps(s.then, &inst, &rows, &ctx) + markClose }
1122. else { out = out + markOpen + runSteps(s.other, &inst, &rows, &ctx) + markClose }
1123. }
1124. else if (s.k == 'opt') {
1125. let head = runSteps(s.attrs, &inst, &rows, &ctx)
1126. let body = runSteps(s.body, &inst, &rows, &ctx)
1127. let mark = ''
1128. if (ctx.sel != null) {
1129. let ov = body
1130. if (s.ov != null) { let f = s.ov ov = '' + f(&inst, &rows) }
1131. if (ov == ctx.sel) { mark = ' selected' }
1132. }
1133. out = out + '<option' + head + mark + '>' + body + '</option>'
1134. }
1135. else if (s.k == 'sel') {
1136. let f = s.read
1137. let inner = ctx + {}
1138. inner.sel = f == null ? null : '' + f(&inst, &rows)
1139. out = out + runSteps(s.body, &inst, &rows, &inner)
1140. }
1141. else if (s.k == 'kid') {
1142. let kid = ctx.kids[v.kidKeyIn(s.path, ctx)]
1143. if (kid == null) { out = out + '<!-- ' + s.cls + ' not mounted -->' }
1144. else {
1145. let fillText = s.fill == null ? null : runSteps(s.fill, &inst, &rows, &ctx)
1146. let kidCtx = { slot = fillText; kids = kid.kids; }
1147. let kidInst = kid.page
1148. let empty = {}
1149. out = out + runSteps(serverSteps(s.key, kid.view, s.indent, s.classes, fillText != null), &kidInst, &empty, &kidCtx)
1150. }
1151. }
1152. }
1153. return out
1154. }