git.iko.soy/rowtype-yoga/purescript-native
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rowtype-yoga/purescript-native/src/Language/PureScript/ModuleDependencies.hs
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1-----------------------------------------------------------------------------
2--
3-- Module : Language.PureScript.ModuleDependencies
4-- Copyright : (c) Phil Freeman 2013
5-- License : MIT
6--
7-- Maintainer : Phil Freeman <paf31@cantab.net>
8-- Stability : experimental
9-- Portability :
10--
11-- | Provides the ability to sort modules based on module dependencies
12--
13-----------------------------------------------------------------------------
15module Language.PureScript.ModuleDependencies (
16 sortModules
17) where
19import Data.Data
20import Data.Graph
21import Data.Generics
22import Data.List (nub, intersect)
23import Control.Applicative ((<$>))
25import Language.PureScript.Declarations
26import Language.PureScript.Names
27import Language.PureScript.Values
28import Language.PureScript.Types
30-- |
31-- Sort a collection of modules based on module dependencies.
32--
33-- Reports an error if the module graph contains a cycle.
34--
35sortModules :: [Module] -> Either String [Module]
36sortModules ms = do
37 let verts = map (\m -> (m, getModuleName m, usedModules m)) ms
38 mapM toModule $ stronglyConnComp verts
40-- |
41-- Calculate a list of used modules based on explicit imports and qualified names
42--
43usedModules :: (Data d) => d -> [ProperName]
44usedModules = nub . everything (++) (mkQ [] qualifiedIdents `extQ` qualifiedProperNames `extQ` imports)
45 where
46 qualifiedIdents :: Qualified Ident -> [ProperName]
47 qualifiedIdents (Qualified (Just (ModuleName pn)) _) = [pn]
48 qualifiedIdents _ = []
49 qualifiedProperNames :: Qualified ProperName -> [ProperName]
50 qualifiedProperNames (Qualified (Just (ModuleName pn)) _) = [pn]
51 qualifiedProperNames _ = []
52 imports :: Declaration -> [ProperName]
53 imports (ImportDeclaration (ModuleName pn) _) = [pn]
54 imports _ = []
56getModuleName :: Module -> ProperName
57getModuleName (Module pn _) = pn
59-- |
60-- Convert a strongly connected component of the module graph to a module
61--
62toModule :: SCC Module -> Either String Module
63toModule (AcyclicSCC m) = return m
64toModule (CyclicSCC [m]) = return m
65toModule (CyclicSCC _) = Left "Cycle in module dependencies"