-----------------------------------------------------------------------------
-- |The Helium Compiler : Static Analysis
--
-- Maintainer  :  bastiaan@cs.uu.nl
-- Stability   :  experimental
-- Portability :  unknown
--
-- Collects information
--
-- (directives based on "Scripting the Type Inference Process", ICFP 2003)
-----------------------------------------------------------------------------
imports {
import Helium.StaticAnalysis.Inferencers.ExpressionTypeInferencer (expressionTypeInferencer)
import qualified Data.Map as M
}

-- Collect all type variables 

ATTR UserStatement UserStatements TypeRule Judgement SimpleJudgement SimpleJudgements 
     Type Types [ | | typevariables USE { ++ } { [] } : Names ]

SEM Type
  | Variable  lhs . typevariables = [ @name.self ]

SEM TypingStrategy
  | TypingStrategy
       loc . uniqueTypevariables = nub (@typerule.typevariables ++ @statements.typevariables)
  
ATTR UserStatement UserStatements TypeRule Judgement SimpleJudgement SimpleJudgements 
     [ nameMap : {[(Name,Tp)]} | | ]
     
-- Construct type constraints from the constraint-set     

ATTR UserStatement UserStatements [ | userConstraints : {TypeConstraints ConstraintInfo} 
                                      userPredicates  : Predicates | ]

SEM TypingStrategy 
  | TypingStrategy
       statements . userConstraints = []
                  . userPredicates  = []
       
SEM UserStatement
  | Equal 
       lhs . userConstraints = @newConstraint : @lhs.userConstraints
       loc . newConstraint   = (makeTpFromType @lhs.nameMap @leftType.self .==. makeTpFromType @lhs.nameMap @rightType.self) @lhs.standardConstraintInfo
  | Pred
       lhs . userPredicates = @newPredicate : @lhs.userPredicates
       loc . newPredicate   = Predicate (show @predClass.self) (makeTpFromType @lhs.nameMap @predType.self)
       
-- Collect judgements in typerule

ATTR SimpleJudgement SimpleJudgements TypeRule [ | simpleJudgements:{[(String,Tp)]} | ]

SEM TypingStrategy
  | TypingStrategy
       typerule . simpleJudgements = []
       
SEM SimpleJudgement
  | SimpleJudgement   
       lhs . simpleJudgements = @newJudgement : @lhs.simpleJudgements       
       loc . newJudgement  = (show @name.self, makeTpFromType @lhs.nameMap @type.self)
                
ATTR Judgement TypeRule [ | | conclusionType : Tp ]

SEM Judgement
  | Judgement   lhs . conclusionType = makeTpFromType @lhs.nameMap @type.self

-- Collecting MetaVariableConstraints

ATTR UserStatements UserStatement [ | metaVariableConstraintNames : Names | ]

SEM TypingStrategy
  | TypingStrategy
       statements . metaVariableConstraintNames = []
       
SEM UserStatement    
  | MetaVariableConstraints
       lhs . metaVariableConstraintNames = @name.self : @lhs.metaVariableConstraintNames
       
SEM TypingStrategy 
  | TypingStrategy  
       loc . allMetaVariables     = map fst @typerule.simpleJudgements 
           . constraintsNotExplicit = filter (`notElem` (map show @statements.metaVariableConstraintNames)) @allMetaVariables       

ATTR UserStatements UserStatement [ standardConstraintInfo : ConstraintInfo
                                    attributeTable : {[((String, Maybe String), MessageBlock)]} | | ]

SEM TypingStrategy
  | TypingStrategy
       loc . standardConstraintInfo = standardConstraintInfo
           . attributeTable         = [] 
   
--

ATTR TypeRule  [ | | conclusionExpression:Expression ]
ATTR Judgement [ | | theExpression:Expression ]
           
SEM TypeRule  | TypeRule   lhs . conclusionExpression = @conclusion.theExpression           
SEM Judgement | Judgement  lhs . theExpression = @expression.self