src/rules/style/param.bend
bolt@1.18.0.0 · 66 lines · 0 definitions
1# rule param: a parameter name shorter than 2 characters. A single uppercase
2# letter is a type parameter (`A`, `T`), and a bare parameter or one typed
3# `Quant` is a quantity. Locals, pattern binders and a law's `for` names are
4# not parameters. A PROOF.bend's parameters are the names the law bound.
5import Base
6import bolt@1.18.0.0/src/paths.bend as Paths
7import bolt@1.18.0.0/src/src.bend as Src
8import bolt@1.18.0.0/src/finding.bend as F
9import bolt@1.18.0.0/src/syntax/bind.bend as Bind
10import bolt@1.18.0.0/src/lazy/lazy.bend as Lazy
11import bolt@1.18.0.0/src/rules/tokens.bend as T
12
13# one character, and a capital: a type parameter
14def check.letter(cs: List<&2, Char>) -> Bool:
15 match cs:
16 case Con{c, Nil{}}:
17 Char.is_upper(c)
18 case other:
19 False{}
20
21# `A`, `T`, `H`
22def check.upper(+nm: String) -> Bool:
23 check.letter(String.to_list(nm))
24
25# no type, or `: Quant`: a quantity parameter (`a` in `List<a, A>`). The
26# note is read with its string literals cut to their quote: a `:` inside a
27# string is no type
28def check.quant(+note: String) -> Bool:
29 +cn = T.code(note)
30 Bool.or(Bool.not(String.contains(cn, ":")), String.ends_with(cn, ": Quant"))
31
32# shorter than 2
33def check.short(+nm: String) -> Bool:
34 Nat.is_lt(String.length(nm), 2n)
35
36# a parameter, not a local or a pattern
37def check.is_param(kk: Bind.BindKind) -> Bool:
38 match kk:
39 case Bind.KParam{}:
40 True{}
41 case other:
42 False{}
43
44# a type parameter or a quantity, which are allowed to be one letter
45def check.allowed(+nm: String, +note: String) -> Bool:
46 Bool.or(check.upper(nm), check.quant(note))
47
48def check.go(binds: List<&2, Bind.Bind>, +path: String) -> List<&2, F.Finding>:
49 match binds:
50 case Nil{}:
51 Nil{}
52 case Con{Bind.Bind{+nm, +line, +col, +kind, +note}, rest}:
53 +more = check.go(rest, path)
54 +hit = Bool.and(check.is_param(kind), Bool.and(check.short(nm), Bool.not(check.allowed(nm, note))))
55 Bool.pick(List<&2, F.Finding>, hit,
56 F.Finding{path, line, col, U32.from_nat(String.length(nm)), "param",
57 "Parameter " ++ nm ++ " is too short; use at least 2 characters."} <> more, more)
58
59def check.on(binds: List<&2, Bind.Bind>, +path: String) -> List<&2, F.Finding>:
60 Lazy.stop(List<&2, F.Finding>, Paths.is_proof(path), [], _u => check.go(binds, path))
61
62# the rule; a proof's parameters stay the law's names
63def check(ss: Src.Src) -> List<&2, F.Finding>:
64 Src.Src{path, text, toks, tree, bound, items} = ss
65 Bind.Bound{binds, uses, scopes} = bound
66 check.on(binds, path)