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	# 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	
20	# what a file holds
21	# -----------------
22	
23	# a law names an item of a module: its path and its name
24	type Mention is Data:
25	  Mention{path: String, name: String}
26	
27	# a top-level def or type, by kind, name and the line it starts on, with a
28	# type's constructors by name (none for a def), and what the uses on its
29	# lines name (its calls, for a def): each as the binder resolved it, an item
30	# of the file or one behind an import alias
31	type Top is Data:
32	  Top{kind: Outline.ItemKind, name: String, line: U32, ctors: List<&2, String>, calls: List<&2, Mention>}
33	
34	# an `@unsafe def` and where its `@` is
35	type Unsafe is Data:
36	  Unsafe{name: String, line: U32, col: U32}
37	
38	# a law of a LAWS.bend: its name, the line it starts on, whether it binds
39	# (a `for` or `exs` line), and the lines of its comment block, `# ` dropped
40	type Law is Data:
41	  Law{name: String, line: U32, binds: Bool, doc: List<&2, String>}
42	
43	# one file as the project rules see it: its path as given and normalized, its
44	# directory, whether it states laws (LAWS.bend) or proves them too
45	# (PROOF.bend), whether the coverage rule lets it off, its top-level items, what
46	# its own laws name, the files it imports, and its `@unsafe` defs
47	type Digest is Data:
48	  Digest{path: String, norm: String, dir: String, is_laws: Bool, is_law_file: Bool, exempt: Bool,
49	    tops: List<&2, Top>, says: List<&2, Mention>, deps: List<&2, String>, unsafes: List<&2, Unsafe>,
50	    laws: List<&2, Law>}
51	
52	# what the laws name
53	# ------------------
54	
55	# an import alias and the path it names
56	type Alias is Data:
57	  Alias{name: String, path: String}
58	
59	# the aliases a file imports
60	def aliases(items: List<&2, Outline.Item>, +from: String) -> List<&2, Alias>:
61	  match items:
62	    case Nil{}:
63	      Nil{}
64	    case Con{Outline.Item{Outline.IImport{}, name, line, sig, doc, path}, rest}:
65	      Alias{name, Imports.resolve(from, path)} <> aliases(rest, from)
66	    case Con{other, rest}:
67	      aliases(rest, from)
68	
69	# the path an alias names, when it is one
70	def alias_path(as: List<&2, Alias>, +name: String) -> Maybe<&2, String>:
71	  match as:
72	    case Nil{}:
73	      None{}
74	    case Con{Alias{+n, p}, rest}:
75	      +more = alias_path(rest, name)
76	      Bool.pick(Maybe<&2, String>, String.eq(n, name), Some{p}, more)
77	
78	# the lines a quantified law's statement spans: from its header's first token
79	# to its body's last
80	type Span is Data:
81	  Span{from: U32, upto: U32}
82	
83	# the spans of every quantified law of a tree, in order. A closed law spans
84	# nothing (it covers one input, not the def)
85	def spans(root: Tree.Node) -> List<&2, Span>:
86	  match root:
87	    case Tree.NCons{Tree.Stmt{Tree.SLaw{}, kids, +body}, rest}:
88	      +more = spans(rest)
89	      Bool.pick(List<&2, Span>, Closed.binds(body),
90	        Span{Tree.line(kids), Tree.line.of(List.head(&2, Lex.Tok, Tree.leaves.go(body, [])))} <> more, more)
91	    case Tree.NCons{h, rest}:
92	      spans(rest)
93	    case other:
94	      Nil{}
95	
96	# is the line in one of the spans?
97	def within(ss: List<&2, Span>, +ln: U32) -> Bool:
98	  match ss:
99	    case Nil{}:
100	      False{}
101	    case Con{Span{+from, +upto}, rest}:
102	      Lazy.or_else(Bool.and(U32.is_le(from, ln), U32.is_le(ln, upto)), _u => within(rest, ln))
103	
104	# an item behind an alias, when an import names the alias, onto the others
105	def aliased(mm: Maybe<&2, String>, +name: String, more: List<&2, Mention>) -> List<&2, Mention>:
106	  match mm:
107	    case Some{p}:
108	      Mention{p, name} <> more
109	    case None{}:
110	      more
111	
112	# what the binder resolved a use to, as a mention onto the others: an item of
113	# the law's own file, or an item of the file an import alias names; nothing
114	# for a binder, a free name, or an alias no import names
115	def target(tt: Bind.Target, +as: List<&2, Alias>, +file: String, more: List<&2, Mention>) -> List<&2, Mention>:
116	  match tt:
117	    case Bind.TItem{n}:
118	      Mention{file, n} <> more
119	    case Bind.TQual{a, n}:
120	      aliased(alias_path(as, a), n, more)
121	    case other:
122	      more
123	
124	# the mentions of every use the binder records in the statement of a
125	# quantified law, in order. Its header's own name is a binder, not a use
126	def mentions(us: List<&2, Bind.Use>, +ss: List<&2, Span>, +as: List<&2, Alias>, +file: String) -> List<&2, Mention>:
127	  match us:
128	    case Nil{}:
129	      Nil{}
130	    case Con{Bind.Use{n, +l, c, tt}, rest}:
131	      +more = mentions(rest, ss, as, file)
132	      Lazy.stop(List<&2, Mention>, Bool.not(within(ss, l)), more, _u => target(tt, as, file, more))
133	
134	# the uses the binder recorded
135	def uses.of(bb: Bind.Bound) -> List<&2, Bind.Use>:
136	  match bb:
137	    case Bind.Bound{bs, us, scs}:
138	      us
139	
140	# what the file holds besides
141	# ---------------------------
142	
143	# the names of the constructors the items open with: a type's, since the
144	# outline lists them right after it
145	def ctors(items: List<&2, Outline.Item>) -> List<&2, String>:
146	  match items:
147	    case Con{Outline.Item{Outline.ICtor{}, name, line, sig, doc, path}, rest}:
148	      name <> ctors(rest)
149	    case other:
150	      Nil{}
151	
152	# the uses, in order, before the first one at or past the line
153	def before(us: List<&2, Bind.Use>, +at: U32) -> List<&2, Bind.Use>:
154	  match us:
155	    case Nil{}:
156	      Nil{}
157	    case Con{Bind.Use{nm, +l, c, tt}, rest}:
158	      Lazy.stop(List<&2, Bind.Use>, U32.is_le(at, l), [], _u => Bind.Use{nm, l, c, tt} <> before(rest, at))
159	
160	# the uses from the first one at or past the line on
161	def after(us: List<&2, Bind.Use>, +at: U32) -> List<&2, Bind.Use>:
162	  match us:
163	    case Nil{}:
164	      Nil{}
165	    case Con{Bind.Use{nm, +l, c, tt}, +rest}:
166	      Lazy.stop(List<&2, Bind.Use>, U32.is_le(at, l), Bind.Use{nm, l, c, tt} <> rest, _u => after(rest, at))
167	
168	# the uses before the line, when there is one; else all of them
169	def upto(us: List<&2, Bind.Use>, mm: Maybe<&2, U32>) -> List<&2, Bind.Use>:
170	  match mm:
171	    case None{}:
172	      us
173	    case Some{at}:
174	      before(us, at)
175	
176	# the uses from the line on, when there is one; else none
177	def past(us: List<&2, Bind.Use>, mm: Maybe<&2, U32>) -> List<&2, Bind.Use>:
178	  match mm:
179	    case None{}:
180	      Nil{}
181	    case Some{at}:
182	      after(us, at)
183	
184	# the line of the next item that ends an item's lines: any but a constructor,
185	# which the outline lists inside its type
186	def next_line(items: List<&2, Outline.Item>) -> Maybe<&2, U32>:
187	  match items:
188	    case Nil{}:
189	      None{}
190	    case Con{Outline.Item{Outline.ICtor{}, name, line, sig, doc, path}, rest}:
191	      next_line(rest)
192	    case Con{Outline.Item{kind, name, line, sig, doc, path}, rest}:
193	      Some{line}
194	
195	# what the uses name, in order: an item of the file, or one behind an alias
196	def called(us: List<&2, Bind.Use>, +as: List<&2, Alias>, +file: String) -> List<&2, Mention>:
197	  match us:
198	    case Nil{}:
199	      Nil{}
200	    case Con{Bind.Use{n, l, c, tt}, rest}:
201	      target(tt, as, file, called(rest, as, file))
202	
203	# the top-level defs and types, by name and line: what the coverage rule
204	# grades. The uses are read in order, once: each item but a constructor
205	# takes those before the next such item's line, and a def or a type keeps
206	# what they name (a def's calls)
207	def ranged(
208	  items: List<&2, Outline.Item>,
209	  +us: List<&2, Bind.Use>,
210	  +as: List<&2, Alias>,
211	  +file: String
212	) -> List<&2, Top>:
213	  match items:
214	    case Nil{}:
215	      Nil{}
216	    case Con{Outline.Item{Outline.ICtor{}, name, line, sig, doc, path}, rest}:
217	      ranged(rest, us, as, file)
218	    case Con{Outline.Item{Outline.IDef{}, name, line, sig, doc, path}, +rest}:
219	      +nx = next_line(rest)
220	      Top{Outline.IDef{}, name, line, [], called(upto(us, nx), as, file)} <> ranged(rest, past(us, nx), as, file)
221	    case Con{Outline.Item{Outline.IType{}, name, line, sig, doc, path}, +rest}:
222	      +nx = next_line(rest)
223	      Top{Outline.IType{}, name, line, ctors(rest), called(upto(us, nx), as, file)}
224	        <> ranged(rest, past(us, nx), as, file)
225	    case Con{Outline.Item{kind, name, line, sig, doc, path}, +rest}:
226	      ranged(rest, past(us, next_line(rest)), as, file)
227	
228	# a law file or a test, by its path alone: not under law. Nothing the file's
229	# text mentions exempts it; IO is not an exemption, since an IO equality is a
230	# law.
231	def is_exempt(+pp: String) -> Bool:
232	  Bool.or(Paths.is_law_file(pp), Paths.is_test(pp))
233	
234	# the significant tokens: no space, newline or comment
235	def significant(toks: List<&2, Lex.Tok>) -> List<&2, Lex.Tok>:
236	  match toks:
237	    case Nil{}:
238	      Nil{}
239	    case Con{Lex.Tok{+k, t, l, c}, rest}:
240	      +more = significant(rest)
241	      Bool.pick(List<&2, Lex.Tok>, Lex.significant(k), Lex.Tok{k, t, l, c} <> more, more)
242	
243	# the name after `unsafe def`, when the tokens run so
244	def unsafe_name(toks: List<&2, Lex.Tok>) -> Maybe<&2, String>:
245	  match toks:
246	    case Con{Lex.Tok{k1, +u, l1, c1}, Con{Lex.Tok{k2, +d, l2, c2}, Con{Lex.Tok{k3, n, l3, c3}, rest}}}:
247	      Bool.pick(Maybe<&2, String>, Bool.and(String.eq(u, "unsafe"), String.eq(d, "def")), Some{n}, None{})
248	    case other:
249	      None{}
250	
251	# an `@` that heads an unsafe def, onto the others
252	def push(mm: Maybe<&2, String>, +ll: U32, +cc: U32, more: List<&2, Unsafe>) -> List<&2, Unsafe>:
253	  match mm:
254	    case None{}:
255	      more
256	    case Some{n}:
257	      Unsafe{n, ll, cc} <> more
258	
259	# every `@ unsafe def name` run of tokens, on one line or two
260	def unsafe_defs(toks: List<&2, Lex.Tok>) -> List<&2, Unsafe>:
261	  match toks:
262	    case Nil{}:
263	      Nil{}
264	    case Con{Lex.Tok{k, +at, +l, +c}, +rest}:
265	      +more = unsafe_defs(rest)
266	      Bool.pick(List<&2, Unsafe>, String.eq(at, "@"), push(unsafe_name(rest), l, c, more), more)
267	
268	# the laws
269	# --------
270	
271	# the doc of the item on a line; the items are in line order, so the search
272	# stops at it
273	def doc_at(items: List<&2, Outline.Item>, +at: U32) -> String:
274	  match items:
275	    case Nil{}:
276	      ""
277	    case Con{Outline.Item{kk, nn, +ln, sig, +doc, pp}, rest}:
278	      Lazy.stop(String, U32.is_le(at, ln), Bool.pick(String, U32.is_eq(ln, at), doc, ""), _u => doc_at(rest, at))
279	
280	# every law of a tree, with whether it binds and its doc lines
281	def laws_of(root: Tree.Node, +items: List<&2, Outline.Item>) -> List<&2, Law>:
282	  match root:
283	    case Tree.NCons{Tree.Stmt{Tree.SLaw{}, +kids, body}, rest}:
284	      +at = Tree.line(kids)
285	      Law{Closed.name.of(Bind.declared(kids)), at, Closed.binds(body), String.lines(doc_at(items, at))}
286	        <> laws_of(rest, items)
287	    case Tree.NCons{h, rest}:
288	      laws_of(rest, items)
289	    case other:
290	      Nil{}
291	
292	# the laws of a LAWS.bend; no other file states any
293	def laws.in(is_laws: Bool, root: Tree.Node, items: List<&2, Outline.Item>) -> List<&2, Law>:
294	  match is_laws:
295	    case True{}:
296	      laws_of(root, items)
297	    case False{}:
298	      Nil{}
299	
300	# the digest
301	# ----------
302	
303	# what a file's laws name: only a LAWS.bend states laws that cover a def
304	def stated(is_laws: Bool, root: Tree.Node, bound: Bind.Bound, as: List<&2, Alias>, file: String) -> List<&2, Mention>:
305	  match is_laws:
306	    case True{}:
307	      mentions(uses.of(bound), spans(root), as, file)
308	    case False{}:
309	      Nil{}
310	
311	# one parsed file read down to its digest
312	def of(s2: Src.Src) -> Digest:
313	  Src.Src{+path, text, toks, +tree, +bound, +items} = s2
314	  +p = Imports.norm(path)
315	  +as = aliases(items, p)
316	  Digest{path, p, Imports.dir_of(path), Paths.is_laws(path), Paths.is_law_file(path), is_exempt(p),
317	    ranged(items, uses.of(bound), as, p), stated(Paths.is_laws(path), tree, bound, as, p), Imports.targets(items, p),
318	    unsafe_defs(significant(toks)), laws.in(Paths.is_laws(path), tree, items)}
319	
320	# every file the linter read, in one pass, in order
321	def all(ss: List<&2, Src.Src>) -> List<&2, Digest>:
322	  match ss:
323	    case Nil{}:
324	      Nil{}
325	    case Con{s, rest}:
326	      of(s) <> all(rest)
327	
328	# the import graph of the files, built once for every closure taken over it
329	def edges(ds: List<&2, Digest>) -> List<&2, Imports.Edge>:
330	  match ds:
331	    case Nil{}:
332	      Nil{}
333	    case Con{Digest{path, norm, dir, is_laws, is_law_file, exempt, tops, says, deps, unsafes, laws}, rest}:
334	      Imports.Edge{norm, deps} <> edges(rest)