git.iko.soy/rowtype-yoga/purescript-native
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rowtype-yoga/purescript-native/src/Language/PureScript/Scope.hs
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1-----------------------------------------------------------------------------
2--
3-- Module : Language.PureScript.Scope
4-- Copyright : (c) Phil Freeman 2013
5-- License : MIT
6--
7-- Maintainer : Phil Freeman <paf31@cantab.net>
8-- Stability : experimental
9-- Portability :
10--
11-- |
12--
13-----------------------------------------------------------------------------
15module Language.PureScript.Scope (
16 usedNames,
17 unusedNames,
18 firstUnusedName
19) where
21import Data.Data
22import Data.List ((\\), nub)
23import Data.Generics (extQ, mkQ, everything)
25import Language.PureScript.Values
26import Language.PureScript.Names
27import Language.PureScript.CodeGen.JS.AST
28import Data.Maybe (mapMaybe)
30usedNames :: (Data d) => d -> [Ident]
31usedNames val = nub $ everything (++) (mkQ [] namesV `extQ` namesS `extQ` namesB `extQ` namesJS) val
32 where
33 namesV :: Value -> [Ident]
34 namesV (Abs args _) = args
35 namesV (Var (Qualified (ModulePath []) name)) = [name]
36 namesV _ = []
37 namesS :: Statement -> [Ident]
38 namesS (VariableIntroduction name _) = [name]
39 namesS (For name _ _ _) = [name]
40 namesS _ = []
41 namesB :: Binder -> [Ident]
42 namesB (VarBinder name) = [name]
43 namesB _ = []
44 namesJS :: JS -> [Ident]
45 namesJS (JSVar name) = [name]
46 namesJS (JSFunction (Just name) args _) = name : args
47 namesJS (JSFunction Nothing args _) = args
48 namesJS (JSVariableIntroduction name _) = [name]
49 namesJS (JSFor name _ _ _) = [name]
50 namesJS _ = []
52unusedNames :: (Data d) => d -> [Ident]
53unusedNames val =
54 let
55 allNames = usedNames val
56 varNames = map (Ident . ('_' :) . show) ([1..] :: [Int])
57 in
58 varNames \\ allNames
60firstUnusedName :: (Data d) => d -> Int
61firstUnusedName val =
62 let
63 allNames = usedNames val
64 varNames = mapMaybe toUnknown allNames
65 in
66 1 + maximum (0 : varNames)
67 where
68 toUnknown :: Ident -> Maybe Int
69 toUnknown (Ident ('_' : s)) = readMaybe s
70 toUnknown _ = Nothing
72readMaybe :: String -> Maybe Int
73readMaybe s = case reads s of
74 [(n, "")] -> Just n
75 _ -> Nothing