source: src/AST/TypeSubstitution.hpp

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// TypeSubstitution.hpp --
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Mon Dec 11 16:07:30 2023
// Update Count     : 15
//

#pragma once

#include <cassert>                   // for assert
#include <list>                      // for list<>::iterator, _List_iterator
#include <unordered_map>
#include <unordered_set>
#include <string>                    // for string, operator!=
#include <utility>                   // for pair

#include "Fwd.hpp"                   // for UniqueId
#include "ParseNode.hpp"
#include "Type.hpp"
#include "Common/SemanticError.hpp"  // for SemanticError
#include "Visitor.hpp"
#include "Decl.hpp"
#include "Expr.hpp"
#include "Node.hpp"

namespace ast {

class TypeSubstitution : public Node {
  public:
        TypeSubstitution();
        template< typename FormalContainer, typename ActualContainer >
        TypeSubstitution( FormalContainer formals, ActualContainer actuals );
        template< typename FormalIterator, typename ActualIterator >
        TypeSubstitution( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin );
        TypeSubstitution( const TypeSubstitution &other );
        virtual ~TypeSubstitution();

        TypeSubstitution &operator=( const TypeSubstitution &other );

        template< typename node_t >
        struct ApplyResult {
                ast::ptr<node_t> node;
                int count;
        };

        template< typename node_t >
        ApplyResult<node_t> apply( const node_t * input ) const {
                ApplyResult<Node> ret = applyBase( input, false );
                return { ret.node.strict_as<node_t>(), ret.count };
        }

        template< typename node_t, enum Node::ref_type ref_t >
        int apply( ptr_base< node_t, ref_t > & input ) const {
                ApplyResult<Node> ret = applyBase( input.get(), false );
                input = ret.node.strict_as<node_t>();
                return ret.count;
        }

        template< typename node_t >
        ApplyResult<node_t> applyFree( const node_t * input ) const {
                ApplyResult<Node> ret = applyBase( input, true );
                return { ret.node.strict_as<node_t>(), ret.count };
        }

        template< typename node_t, enum Node::ref_type ref_t >
        int applyFree( ptr_base< node_t, ref_t > & input ) const {
                ApplyResult<Node> ret = applyBase( input.get(), true );
                input = ret.node.strict_as<node_t>();
                return ret.count;
        }

        void add( const TypeInstType * formalType, const Type *actualType );
        void add( const TypeEnvKey & key, const Type *actualType );
        void add( const TypeSubstitution &other );
        void remove( const TypeInstType * formalType );
        const Type *lookup( const TypeEnvKey & formalType ) const;
        const Type *lookup( const TypeInstType * formalType ) const;
        bool empty() const;

        template< typename FormalContainer, typename ActualContainer >
        void addAll( FormalContainer formals, ActualContainer actuals );
        template< typename FormalIterator, typename ActualIterator >
        void addAll( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin );

        /// create a new TypeSubstitution using bindings from env containing all of the type variables in expr
        static TypeSubstitution * newFromExpr( const Expr * expr, const TypeSubstitution * env );

        void normalize();

        const TypeSubstitution * accept( Visitor & v ) const override { return v.visit( this ); }

        TypeSubstitution * clone() const override { return new TypeSubstitution( *this ); }

  private:

        // Mutator that performs the substitution
        struct Substituter;
        ApplyResult<Node> applyBase( const Node * input, bool isFree ) const;

        // TODO: worry about traversing into a forall-qualified function type or type decl with assertions

        void initialize( const TypeSubstitution &src, TypeSubstitution &dest );

        template<typename core_t>
        friend class Pass;

        typedef std::unordered_map< TypeEnvKey, ptr<Type> > TypeMap;
        TypeMap typeMap;

  public:
        // has to come after declaration of typeMap
        auto begin()       -> decltype( typeMap.begin() ) { return typeMap.begin(); }
        auto   end()       -> decltype( typeMap.  end() ) { return typeMap.  end(); }
        auto begin() const -> decltype( typeMap.begin() ) { return typeMap.begin(); }
        auto   end() const -> decltype( typeMap.  end() ) { return typeMap.  end(); }

};

template< typename FormalContainer, typename ActualContainer >
TypeSubstitution::TypeSubstitution( FormalContainer formals, ActualContainer actuals ) {
        assert( formals.size() == actuals.size() );
        addAll( formals.begin(), formals.end(), actuals.begin() );
}

template< typename FormalIterator, typename ActualIterator >
TypeSubstitution::TypeSubstitution( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin ) {
        addAll( formalBegin, formalEnd, actualBegin );
}

template< typename FormalContainer, typename ActualContainer >
void TypeSubstitution::addAll( FormalContainer formals, ActualContainer actuals ) {
        assert( formals.size() == actuals.size() );
        addAll( formals.begin(), formals.end(), actuals.begin() );
}

// this is the only place where type parameters outside a function formal may be substituted.
template< typename FormalIterator, typename ActualIterator >
void TypeSubstitution::addAll( FormalIterator formalBegin, FormalIterator formalEnd, ActualIterator actualBegin ) {
        // FormalIterator points to a TypeDecl
        // ActualIterator points to a Type
        FormalIterator formalIt = formalBegin;
        ActualIterator actualIt = actualBegin;
        for ( ; formalIt != formalEnd; ++formalIt, ++actualIt ) {
                if ( const TypeDecl *formal = formalIt->template as<TypeDecl>() ) {
                        if ( const TypeExpr *actual = actualIt->template as<TypeExpr>() ) {
                                if ( formal->name != "" ) {
                                        typeMap[ formal ] = actual->type;
                                } // if
                        } else {
                                SemanticError( formal->location, "Attempt to provide non-type parameter %s for type parameter %s",
                                                           toString( *actualIt ).c_str(), formal->name.c_str() );
                        } // if
                } else {
                        // Is this an error?
                } // if
        } // for
}

} // namespace ast

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// mode: c++ //
// compile-command: "make install" //
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