1	# src/rules/digest: one small reading of each file for the project rules.
2	# A project rule sees every file at once, and a `+` reuse of that list copies
3	# it: handed the parsed `Src` (src/src.bend), each extra use duplicated every
4	# file's text, tokens and tree, and the pair of project rules grew faster than
5	# the file count (100 files cost 362 s that way). So each file is read down
6	# once to what those rules ask of it -- its path, its top-level defs and types
7	# by name and line, what its laws name, what it imports, and its `@unsafe`
8	# and foreign defs -- and the phases run over these, which are strings and cheap to copy.
9	import Base
10	import ../src.bend as Src
11	import ../syntax/lex.bend as Lex
12	import ../syntax/tree.bend as Tree
13	import ../syntax/bind.bend as Bind
14	import ../syntax/outline.bend as Outline
15	import ../lazy/lazy.bend as Lazy
16	import ./imports.bend as Imports
17	import ./laws/closed.bend as Closed
18	import ../paths.bend as Paths
19	import ../role.bend as Role
20	import ./correctness/foreign.bend as Foreign
21	import ./calls.bend as Calls
22	
23	# what a file holds
24	# -----------------
25	
26	# a law names an item of a module: its path and its name
27	type Mention is Data:
28	  Mention{path: String, name: String}
29	
30	# a top-level def or type, by kind, name and the line it starts on, with a
31	# type's constructors by name (none for a def), and what the uses on its
32	# lines name (its calls, for a def): each as the binder resolved it, an item
33	# of the file or one behind an import alias
34	type Top is Data:
35	  Top{kind: Outline.ItemKind, name: String, line: U32, ctors: List<&2, String>, calls: List<&2, Mention>}
36	
37	# a def a proof may not reach (bend 2.0.32): an `@unsafe def`, where its
38	# `@` is, or a foreign def (its body only `import "./x.c"` / `import
39	# "./x.js"` lines), where its header starts; foreign says which
40	type Unsafe is Data:
41	  Unsafe{name: String, line: U32, col: U32, foreign: Bool}
42	
43	# a law of a LAWS.bend: its name, the line it starts on, whether it binds
44	# (a `for` or `exs` line), and the lines of its comment block, `# ` dropped
45	type Law is Data:
46	  Law{name: String, line: U32, binds: Bool, doc: List<&2, String>}
47	
48	# one file as the project rules see it: its path as given and normalized, its
49	# directory, whether it states laws (LAWS.bend) or proves them too
50	# (PROOF.bend), whether the coverage rule lets it off, its top-level items, what
51	# its own laws name, the files it imports, its `@unsafe` and foreign defs
52	type Digest is Data:
53	  Digest{path: String, norm: String, dir: String, is_laws: Bool, is_law_file: Bool, exempt: Bool,
54	    tops: List<&2, Top>, says: List<&2, Mention>, deps: List<&2, String>, unsafes: List<&2, Unsafe>,
55	    laws: List<&2, Law>}
56	
57	# what the laws name
58	# ------------------
59	
60	# an import alias and the path it names
61	type Alias is Data:
62	  Alias{name: String, path: String}
63	
64	# the aliases a file imports
65	def aliases(items: List<&2, Outline.Item>, +from: String) -> List<&2, Alias>:
66	  match items:
67	    case Nil{}:
68	      Nil{}
69	    case Con{Outline.Item{Outline.IImport{}, name, line, sig, doc, path}, rest}:
70	      Alias{name, Imports.resolve(from, path)} <> aliases(rest, from)
71	    case Con{other, rest}:
72	      aliases(rest, from)
73	
74	# the path an alias names, when it is one; hit: the alias before as was
75	# the name, so the search stops there
76	def alias_path.go(as: List<&2, Alias>, +name: String, hit: Maybe<&2, String>) -> Maybe<&2, String>:
77	  match as:
78	    case Nil{}:
79	      hit
80	    case Con{Alias{+n, p}, rest}:
81	      match hit:
82	        case Some{x}:
83	          Some{x}
84	        case None{}:
85	          alias_path.go(rest, name, Bool.pick(Maybe<&2, String>, String.eq(n, name), Some{p}, None{}))
86	
87	# the path an alias names, when it is one: the first alias of the name
88	def alias_path(as: List<&2, Alias>, +name: String) -> Maybe<&2, String>:
89	  alias_path.go(as, name, None{})
90	
91	# the lines a quantified law's statement spans: from its header's first token
92	# to its body's last
93	type Span is Data:
94	  Span{from: U32, upto: U32}
95	
96	# the spans of every quantified law of a tree, in order. A closed law spans
97	# nothing (it covers one input, not the def)
98	def spans(root: Tree.Node) -> List<&2, Span>:
99	  match root:
100	    case Tree.NCons{Tree.Stmt{Tree.SLaw{}, kids, +body}, rest}:
101	      +more = spans(rest)
102	      Bool.pick(List<&2, Span>, Closed.binds(body),
103	        Span{Tree.line(kids), Tree.line.of(List.head(&2, Lex.Tok, Tree.leaves.go(body, [])))} <> more, more)
104	    case Tree.NCons{h, rest}:
105	      spans(rest)
106	    case other:
107	      Nil{}
108	
109	# is the line in one of the spans?
110	def within(ss: List<&2, Span>, +ln: U32) -> Bool:
111	  match ss:
112	    case Nil{}:
113	      False{}
114	    case Con{Span{+from, +upto}, rest}:
115	      Lazy.or_else(Bool.and(U32.is_le(from, ln), U32.is_le(ln, upto)), _u => within(rest, ln))
116	
117	# an item behind an alias, when an import names the alias, onto the others
118	def aliased(mm: Maybe<&2, String>, +name: String, more: List<&2, Mention>) -> List<&2, Mention>:
119	  match mm:
120	    case Some{p}:
121	      Mention{p, name} <> more
122	    case None{}:
123	      more
124	
125	# what the binder resolved a use to, as a mention onto the others: an item of
126	# the law's own file, or an item of the file an import alias names; nothing
127	# for a binder, a free name, or an alias no import names
128	def target(tt: Bind.Target, +as: List<&2, Alias>, +file: String, more: List<&2, Mention>) -> List<&2, Mention>:
129	  match tt:
130	    case Bind.TItem{n}:
131	      Mention{file, n} <> more
132	    case Bind.TQual{a, n}:
133	      aliased(alias_path(as, a), n, more)
134	    case other:
135	      more
136	
137	# the mentions of every use the binder records in the statement of a
138	# quantified law, in order. Its header's own name is a binder, not a use
139	def mentions(us: List<&2, Bind.Use>, +ss: List<&2, Span>, +as: List<&2, Alias>, +file: String) -> List<&2, Mention>:
140	  match us:
141	    case Nil{}:
142	      Nil{}
143	    case Con{Bind.Use{n, +l, c, tt}, rest}:
144	      +more = mentions(rest, ss, as, file)
145	      +out = Bool.not(within(ss, l))
146	      Lazy.stop(List<&2, Mention>, out, more, _u => target(tt, as, file, more))
147	
148	# the uses the binder recorded
149	def uses.of(bb: Bind.Bound) -> List<&2, Bind.Use>:
150	  match bb:
151	    case Bind.Bound{bs, us, scs}:
152	      us
153	
154	# what the file holds besides
155	# ---------------------------
156	
157	# the names of the constructors the items open with: a type's, since the
158	# outline lists them right after it
159	def ctors(items: List<&2, Outline.Item>) -> List<&2, String>:
160	  match items:
161	    case Con{Outline.Item{Outline.ICtor{}, name, line, sig, doc, path}, rest}:
162	      name <> ctors(rest)
163	    case other:
164	      Nil{}
165	
166	# the uses, in order, before the first one at or past the line
167	def before(us: List<&2, Bind.Use>, +at: U32) -> List<&2, Bind.Use>:
168	  match us:
169	    case Nil{}:
170	      Nil{}
171	    case Con{Bind.Use{nm, +l, c, tt}, rest}:
172	      Lazy.stop(List<&2, Bind.Use>, U32.is_le(at, l), [], _u => Bind.Use{nm, l, c, tt} <> before(rest, at))
173	
174	# the uses from the first one at or past the line on
175	def after(us: List<&2, Bind.Use>, +at: U32) -> List<&2, Bind.Use>:
176	  match us:
177	    case Nil{}:
178	      Nil{}
179	    case Con{Bind.Use{nm, +l, c, tt}, +rest}:
180	      Lazy.stop(List<&2, Bind.Use>, U32.is_le(at, l), Bind.Use{nm, l, c, tt} <> rest, _u => after(rest, at))
181	
182	# the uses before the line, when there is one; else all of them
183	def upto(us: List<&2, Bind.Use>, mm: Maybe<&2, U32>) -> List<&2, Bind.Use>:
184	  match mm:
185	    case None{}:
186	      us
187	    case Some{at}:
188	      before(us, at)
189	
190	# the uses from the line on, when there is one; else none
191	def past(us: List<&2, Bind.Use>, mm: Maybe<&2, U32>) -> List<&2, Bind.Use>:
192	  match mm:
193	    case None{}:
194	      Nil{}
195	    case Some{at}:
196	      after(us, at)
197	
198	# the line of the next item that ends an item's lines: any but a constructor,
199	# which the outline lists inside its type
200	def next_line(items: List<&2, Outline.Item>) -> Maybe<&2, U32>:
201	  match items:
202	    case Nil{}:
203	      None{}
204	    case Con{Outline.Item{Outline.ICtor{}, name, line, sig, doc, path}, rest}:
205	      next_line(rest)
206	    case Con{Outline.Item{kind, name, line, sig, doc, path}, rest}:
207	      Some{line}
208	
209	# what the uses name, in order: an item of the file, or one behind an alias
210	def called(us: List<&2, Bind.Use>, +as: List<&2, Alias>, +file: String) -> List<&2, Mention>:
211	  match us:
212	    case Nil{}:
213	      Nil{}
214	    case Con{Bind.Use{n, l, c, tt}, rest}:
215	      target(tt, as, file, called(rest, as, file))
216	
217	# the names of the top-level defs that are proofs (Calls.proof: one that
218	# returns a proof, or one written with no type, which is how Bend fills the
219	# law named f). The law states their property, so the coverage rule neither
220	# grades them nor walks through them
221	def proofs(ds: List<&2, Calls.Def>) -> List<&2, String>:
222	  match ds:
223	    case Nil{}:
224	      Nil{}
225	    case Con{Calls.Def{name, +sig, body}, rest}:
226	      +more = proofs(rest)
227	      Bool.pick(List<&2, String>, Calls.proof(sig), name <> more, more)
228	
229	# the top-level defs and types, by name and line, less the defs that are
230	# proofs (ps): what the coverage rule grades. The uses are read in order,
231	# once: each item but a constructor takes those before the next such item's
232	# line, and a def or a type keeps what they name (a def's calls)
233	def ranged(
234	  items: List<&2, Outline.Item>,
235	  +us: List<&2, Bind.Use>,
236	  +as: List<&2, Alias>,
237	  +file: String,
238	  +ps: List<&2, String>
239	) -> List<&2, Top>:
240	  match items:
241	    case Nil{}:
242	      Nil{}
243	    case Con{Outline.Item{Outline.ICtor{}, name, line, sig, doc, path}, rest}:
244	      ranged(rest, us, as, file, ps)
245	    case Con{Outline.Item{Outline.IDef{}, +name, line, sig, doc, path}, +rest}:
246	      +nx = next_line(rest)
247	      cs = called(upto(us, nx), as, file)
248	      +more = ranged(rest, past(us, nx), as, file, ps)
249	      Bool.pick(List<&2, Top>, Imports.has(ps, name), more, Top{Outline.IDef{}, name, line, [], cs} <> more)
250	    case Con{Outline.Item{Outline.IType{}, name, line, sig, doc, path}, +rest}:
251	      +nx = next_line(rest)
252	      Top{Outline.IType{}, name, line, ctors(rest), called(upto(us, nx), as, file)}
253	        <> ranged(rest, past(us, nx), as, file, ps)
254	    case Con{Outline.Item{kind, name, line, sig, doc, path}, +rest}:
255	      ranged(rest, past(us, next_line(rest)), as, file, ps)
256	
257	# a law file or a test, by its path alone: not under law. Nothing the file's
258	# text mentions exempts it; IO is not an exemption, since an IO equality is a
259	# law.
260	def is_exempt(+pp: String) -> Bool:
261	  Bool.or(Paths.is_law_file(pp), Paths.is_test(pp))
262	
263	# the significant tokens: no space, newline or comment
264	def significant(toks: List<&2, Lex.Tok>) -> List<&2, Lex.Tok>:
265	  match toks:
266	    case Nil{}:
267	      Nil{}
268	    case Con{Lex.Tok{+k, t, l, c}, rest}:
269	      +more = significant(rest)
270	      Bool.pick(List<&2, Lex.Tok>, Lex.significant(k), Lex.Tok{k, t, l, c} <> more, more)
271	
272	# the name after `unsafe def`, when the tokens run so
273	def unsafe_name(toks: List<&2, Lex.Tok>) -> Maybe<&2, String>:
274	  match toks:
275	    case Con{Lex.Tok{k1, +u, l1, c1}, Con{Lex.Tok{k2, +d, l2, c2}, Con{Lex.Tok{k3, n, l3, c3}, rest}}}:
276	      Bool.pick(Maybe<&2, String>, Bool.and(String.eq(u, "unsafe"), String.eq(d, "def")), Some{n}, None{})
277	    case other:
278	      None{}
279	
280	# an `@` that heads an unsafe def, onto the others
281	def push(mm: Maybe<&2, String>, +ll: U32, +cc: U32, more: List<&2, Unsafe>) -> List<&2, Unsafe>:
282	  match mm:
283	    case None{}:
284	      more
285	    case Some{n}:
286	      Unsafe{n, ll, cc, False{}} <> more
287	
288	# every `@ unsafe def name` run of tokens, on one line or two
289	def unsafe_defs(toks: List<&2, Lex.Tok>) -> List<&2, Unsafe>:
290	  match toks:
291	    case Nil{}:
292	      Nil{}
293	    case Con{Lex.Tok{k, +at, +l, +c}, +rest}:
294	      +more = unsafe_defs(rest)
295	      Bool.pick(List<&2, Unsafe>, String.eq(at, "@"), push(unsafe_name(rest), l, c, more), more)
296	
297	# a foreign def, when its body is one (Foreign.lanes), onto the others
298	def foreign.push(
299	  mm: Maybe<&2, Foreign.Lanes>,
300	  +name: String,
301	  +ll: U32,
302	  +cc: U32,
303	  more: List<&2, Unsafe>
304	) -> List<&2, Unsafe>:
305	  match mm:
306	    case None{}:
307	      more
308	    case Some{_lanes}:
309	      Unsafe{name, ll, cc, True{}} <> more
310	
311	# every top-level foreign def, where its header starts
312	def foreign_defs(root: Tree.Node) -> List<&2, Unsafe>:
313	  match root:
314	    case Tree.NCons{Tree.Stmt{Tree.SDef{}, +kids, body}, rest}:
315	      foreign.push(Foreign.lanes(body), Foreign.name.of(Bind.declared(kids)), Tree.line(kids), Tree.col(kids),
316	        foreign_defs(rest))
317	    case Tree.NCons{h, rest}:
318	      foreign_defs(rest)
319	    case other:
320	      Nil{}
321	
322	# the laws
323	# --------
324	
325	# the doc of the item on a line; the items are in line order, so the search
326	# stops at it
327	def doc_at(items: List<&2, Outline.Item>, +at: U32) -> String:
328	  match items:
329	    case Nil{}:
330	      ""
331	    case Con{Outline.Item{kk, nn, +ln, sig, +doc, pp}, rest}:
332	      Lazy.stop(String, U32.is_le(at, ln), Bool.pick(String, U32.is_eq(ln, at), doc, ""), _u => doc_at(rest, at))
333	
334	# does the first item sit on or after a line (from_line stops there)?
335	def from_line.stop(items: List<&2, Outline.Item>, +at: U32) -> Bool:
336	  match items:
337	    case Nil{}:
338	      True{}
339	    case Con{Outline.Item{kk, nn, +ln, sig, doc, pp}, rest}:
340	      U32.is_le(at, ln)
341	
342	# the items from the first on or after a line; the items are in line order,
343	# and so are a tree's laws, so an item this drops lies above every later law
344	# too. stop is from_line.stop of items, carried so the step stays a loop
345	def from_line(items: List<&2, Outline.Item>, +at: U32, +stop: Bool) -> List<&2, Outline.Item>:
346	  match items:
347	    case Nil{}:
348	      Nil{}
349	    case Con{h, +rest}:
350	      match stop:
351	        case True{}:
352	          h <> rest
353	        case False{}:
354	          from_line(rest, at, from_line.stop(rest, at))
355	
356	# every law of a tree, with whether it binds and its doc lines. items is a
357	# cursor: each law's search starts where the last one stopped, so the items
358	# are read once over all the laws, not once per law
359	def laws_of(root: Tree.Node, +items: List<&2, Outline.Item>) -> List<&2, Law>:
360	  match root:
361	    case Tree.NCons{Tree.Stmt{Tree.SLaw{}, +kids, body}, rest}:
362	      +at = Tree.line(kids)
363	      +left = from_line(items, at, from_line.stop(items, at))
364	      dd = doc_at(left, at)
365	      Law{Closed.name.of(Bind.declared(kids)), at, Closed.binds(body), String.lines(dd)} <> laws_of(rest, left)
366	    case Tree.NCons{h, rest}:
367	      laws_of(rest, items)
368	    case other:
369	      Nil{}
370	
371	# the laws of a LAWS.bend; no other file states any
372	def laws.in(is_laws: Bool, root: Tree.Node, items: List<&2, Outline.Item>) -> List<&2, Law>:
373	  match is_laws:
374	    case True{}:
375	      laws_of(root, items)
376	    case False{}:
377	      Nil{}
378	
379	# the digest
380	# ----------
381	
382	# what a file's laws name: only a LAWS.bend states laws that cover a def
383	def stated(is_laws: Bool, root: Tree.Node, bound: Bind.Bound, as: List<&2, Alias>, file: String) -> List<&2, Mention>:
384	  match is_laws:
385	    case True{}:
386	      mentions(uses.of(bound), spans(root), as, file)
387	    case False{}:
388	      Nil{}
389	
390	# one parsed file read down to its digest
391	def of(s2: Src.Src) -> Digest:
392	  Src.Src{+path, text, toks, +tree, +bound, +items} = s2
393	  +p = Imports.norm(path)
394	  +as = aliases(items, p)
395	  Digest{path, p, Imports.dir_of(path), Paths.is_laws(path), Paths.is_law_file(path), is_exempt(p),
396	    ranged(items, uses.of(bound), as, p, proofs(Calls.defs(tree))), stated(Paths.is_laws(path), tree, bound, as, p),
397	    Imports.targets(items, p),
398	    List.append(&2, Unsafe, unsafe_defs(significant(toks)), foreign_defs(tree)),
399	    laws.in(Paths.is_laws(path), tree, items)}
400	
401	# one parsed file read down to its digest, told its role (src/role.bend): a
402	# law file states the laws that cover defs, and a law or proof file is exempt
403	def of.role(+rr: Role.Role, s2: Src.Src) -> Digest:
404	  Src.Src{+path, text, toks, +tree, +bound, +items} = s2
405	  +p = Imports.norm(path)
406	  +as = aliases(items, p)
407	  +laws = Role.is_laws(rr)
408	  Digest{path, p, Imports.dir_of(path), laws, Role.is_law_file(rr), Bool.or(Role.is_law_file(rr), Paths.is_test(p)),
409	    ranged(items, uses.of(bound), as, p, proofs(Calls.defs(tree))), stated(laws, tree, bound, as, p),
410	    Imports.targets(items, p),
411	    List.append(&2, Unsafe, unsafe_defs(significant(toks)), foreign_defs(tree)),
412	    laws.in(laws, tree, items)}
413	
414	# one parsed file's digest, told its role among the marks (src/role.bend)
415	def of.marked(+ms: List<&2, Role.Mark>, s2: Src.Src) -> Digest:
416	  Src.Src{+path, text, toks, tree, bound, items} = s2
417	  of.role(Role.of(ms, path), Src.Src{path, text, toks, tree, bound, items})
418	
419	# every file the linter read, each with its role among the marks, in one
420	# pass, in order
421	def all.role(+ms: List<&2, Role.Mark>, ss: List<&2, Src.Src>) -> List<&2, Digest>:
422	  match ss:
423	    case Nil{}:
424	      Nil{}
425	    case Con{s, rest}:
426	      of.marked(ms, s) <> all.role(ms, rest)
427	
428	# the import graph of the files, built once for every closure taken over it
429	def edges(ds: List<&2, Digest>) -> List<&2, Imports.Edge>:
430	  match ds:
431	    case Nil{}:
432	      Nil{}
433	    case Con{Digest{path, norm, dir, is_laws, is_law_file, exempt, tops, says, deps, unsafes, laws}, rest}:
434	      Imports.Edge{norm, deps} <> edges(rest)