-- GeNeRaTeD fOr: ../../CBS/Funcons/Computations/Data flow/Linking/follow-link.aterm
{-# LANGUAGE OverloadedStrings #-}

module Funcons.Core.Computations.DataFlow.Linking.FollowLink where

import Funcons.EDSL

entities = []

types = typeEnvFromList
    []

funcons = libFromList
    [("follow-link",StrictFuncon stepFollow_link)]

-- |
-- /follow-link(L)/ gives the value linked to by /L/ .
--   If this value is /uninitialised/ , then computation /fail/ s.
follow_link_ fargs = FApp "follow-link" (FTuple fargs)
stepFollow_link fargs =
    evalRules [] [step1,step2,step3]
    where step1 = do
            let env = emptyEnv
            env <- lifted_vsMatch fargs [VPMetaVar "L"] env
            env <- getMutPatt "link-store" (VPMetaVar "Sigma") env
            env <- lifted_sideCondition (SCPatternMatch (TApp "lookup" (TTuple [TVar "L",TVar "Sigma"])) (VPMetaVar "V")) env
            env <- lifted_sideCondition (SCNotInSort (TVar "V") (TName "uninitialised-values")) env
            putMutTerm "link-store" (TTuple [TVar "Sigma"]) env
            stepTermTo (TVar "V") env
          step2 = do
            let env = emptyEnv
            env <- lifted_vsMatch fargs [VPMetaVar "L"] env
            env <- getMutPatt "link-store" (VPMetaVar "Sigma") env
            env <- lifted_sideCondition (SCIsInSort (TApp "lookup" (TTuple [TVar "L",TVar "Sigma"])) (TName "uninitialised-values")) env
            putMutTerm "link-store" (TTuple [TVar "Sigma"]) env
            stepTo (FName "fail")
          step3 = do
            let env = emptyEnv
            env <- lifted_vsMatch fargs [VPMetaVar "L"] env
            env <- getMutPatt "link-store" (VPMetaVar "Sigma") env
            env <- lifted_sideCondition (SCEquality (TApp "is-in-set" (TTuple [TVar "L",TApp "domain" (TTuple [TVar "Sigma"])])) (TName "false")) env
            putMutTerm "link-store" (TTuple [TVar "Sigma"]) env
            stepTo (FName "fail")