-- GeNeRaTeD fOr: ../../CBS/Funcons/Computations/Control flow/Normal/Iterating/Definite/Filtering collections/list-filter.aterm
{-# LANGUAGE OverloadedStrings #-}

module Funcons.Core.Computations.ControlFlow.Normal.Iterating.Definite.FilteringCollections.ListFilter where

import Funcons.EDSL

entities = []

types = typeEnvFromList
    []

funcons = libFromList
    [("list-filter",PartiallyStrictFuncon [NonStrict,Strict] stepList_filter)]

-- |
-- /list-filter(P,L)/ discards all elements from the list /L/ that do not
--   satisify the predicate /P/ .
list_filter_ fargs = FApp "list-filter" (FTuple fargs)
stepList_filter fargs@[arg1,arg2] =
    evalRules [rewrite1,rewrite2] []
    where rewrite1 = do
            let env = emptyEnv
            env <- fsMatch fargs [PMetaVar "P",PValue (PList [])] env
            rewriteTo (FList [])
          rewrite2 = do
            let env = emptyEnv
            env <- fsMatch fargs [PMetaVar "P",PValue (PList [VPMetaVar "V",VPSeqVar "V*" StarOp])] env
            rewriteTermTo (TApp "if-then-else" (TTuple [TApp "give" (TTuple [TVar "V",TVar "P"]),TApp "cons" (TTuple [TVar "V",TApp "list-filter" (TTuple [TVar "P",TList [TVar "V*"]])]),TApp "list-filter" (TTuple [TVar "P",TList [TVar "V*"]])])) env
stepList_filter fargs = sortErr (FApp "list-filter" (FTuple fargs)) "invalid number of arguments"