source: liacs/coco/assignment2/coercion.cc@ 144

#include "coercion.h"
#include "messages.h"
#include "types.h"
#include "Node.h"
#include "SyntaxTree.h"
#include "Symbol.h"
#include <assert.h>

extern int lineno; // declared in comp.l
extern SyntaxTree *tree; // declared in comp.y
extern Messages messages; // declared in comp.y

ReturnType minimumtype(ReturnType lhs, ReturnType rhs)
{
    if (lhs == RT_REAL || rhs == RT_REAL) {
        return RT_REAL;
    } else {
        return RT_INT;
    }
}

void checkType(ReturnType expected, ReturnType actual) {
    if (actual != expected) {
        messages.TypeError(lineno, expected, actual);
    }
}

void checkType(ReturnType expected, Node *expression) {
    checkType(expected, expression->GetReturnType());
}

Node *coerce(ReturnType to, Node *expression)
{
    if (to == RT_ERROR) {
        /* ignore coercions to error type */
        return expression;
    }

    assert(expression != NULL);
    ReturnType from = expression->GetReturnType();

    if (from == to) {
        /* no coercion needed */
        return expression;
    }

    if (from == RT_ERROR) {
        /* always coerce error type */
        return tree->CreateParentNode(NODE_COERCION, to, expression);
    }

    if (from == RT_INT && to == RT_REAL) {
        /* coerce integer to real */
        messages.CoercionWarning(lineno, to, from);
        return tree->CreateParentNode(NODE_COERCION, to, expression);
    }

  if (from == RT_INT && to == RT_BOOL) {
  /* coerce integer to bool */
    messages.CoercionWarning(lineno, to, from);
    return tree->CreateParentNode(NODE_COERCION, to, expression);
  }

  if (from == RT_BOOL && to == RT_INT) {
  /* ../tests/varia/bitwise.p0: coerce bool to integer */
    messages.CoercionWarning(lineno, to, from);
    return tree->CreateParentNode(NODE_COERCION, to, expression);
  }

    /* no coercion possible */
    messages.TypeError(lineno, to, from);
    return expression;
}

void check_parameters(Node *call_node)
{
    assert(call_node != NULL);
    assert(call_node->GetNodeType() == NODE_PROCCALL ||
           call_node->GetNodeType() == NODE_FUNCTIONCALL);

    Node *expression_list = call_node->GetRightChild();
    assert(expression_list->GetNodeType() == NODE_EXPRLIST ||
           expression_list->GetNodeType() == NODE_EMPTY);

    Node *node_id = call_node->GetLeftChild();
    assert(node_id->GetNodeType() == NODE_ID);

    Symbol *symbol = node_id->GetSymbol();
    assert(symbol->GetSymbolType() == ST_PROCEDURE ||
           symbol->GetSymbolType() == ST_FUNCTION);
    if (symbol->GetReturnType() == RT_ERROR) {
        return;
    }

    /* Go through parameters */
    int parametercount = 0;
    while (expression_list->GetNodeType() != NODE_EMPTY) {
        ++parametercount;
        if (parametercount > symbol->GetParameterCount()) {
            break;
        }

        /* Check parameter and add coercion if necessary */
        ReturnType wanted = symbol->GetParameter(parametercount-1)->GetReturnType();
        Node *coerced_node = coerce(wanted, expression_list->GetLeftChild());
        expression_list->SetLeftChild(coerced_node);

        /* Next parameter */
        expression_list = expression_list->GetRightChild();
        assert(expression_list->GetNodeType() == NODE_EXPRLIST || 
               expression_list->GetNodeType() == NODE_EMPTY);
    }
    if (parametercount != symbol->GetParameterCount()) {
        messages.ParamCountError(lineno, parametercount, symbol);
    }
}