bool CAstStatReturn::TypeCheck(CToken *t, string *msg) const
{
const CType *st = GetScope()->GetType();
CAstExpression *e = GetExpression();
if (st->Match(CTypeManager::Get()->GetNull())) {
if (e != NULL) {
if (t != NULL) *t = e->GetToken();
if (msg != NULL) *msg = "superfluous expression after return.";
return false;
}
} else {
if (e == NULL) {
if (t != NULL) *t = GetToken();
if (msg != NULL) *msg = "expression expected after return.";
return false;
}
if (!e->TypeCheck(t, msg)) return false;
if (!st->Match(e->GetType())) {
if (t != NULL) *t = e->GetToken();
if (msg != NULL) *msg = "return type mismatch.";
return false;
}
}
return true;
}
CAstStatCall* CParser::subroutineCall(CAstScope *s, CToken ident) {
//
// subroutineCall ::= ident "(" [ expression {"," expression} ] ")".
//
CToken t;
Consume(tLBrak);
CSymtab *symtab = s->GetSymbolTable();
CAstFunctionCall *call = NULL;
// Check undefined procedure/function call.
if(symtab->FindSymbol(ident.GetValue(), sLocal) == NULL && symtab->FindSymbol(ident.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(ident.GetValue(), sGlobal)) == NULL)
SetError(ident, "invalid procedure/function identifier.");
call = new CAstFunctionCall(ident, dynamic_cast<const CSymProc *>(symtab->FindSymbol(ident.GetValue(), sGlobal)));
}
else if(symtab->FindSymbol(ident.GetValue(), sLocal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(ident.GetValue(), sLocal)) == NULL)
SetError(ident, "invalid procedure/function identifier.");
call = new CAstFunctionCall(ident, dynamic_cast<const CSymProc *>(symtab->FindSymbol(ident.GetValue(), sLocal)));
}
else
SetError(ident, "undefined identifier.");
// Add expressions.
if(isExpr(_scanner->Peek())) {
CAstExpression *expr = expression(s);
assert(expr != NULL);
// Arrays are addressed.
if(expr->GetType()->IsArray())
expr = new CAstSpecialOp(expr->GetToken(), opAddress, expr, NULL);
call->AddArg(expr);
while(_scanner->Peek().GetType() == tComma) {
Consume(tComma);
expr = expression(s);
assert(expr != NULL);
// Arrays are addressed.
if(expr->GetType()->IsArray())
expr = new CAstSpecialOp(expr->GetToken(), opAddress, expr, NULL);
call->AddArg(expr);
}
}
Consume(tRBrak);
return new CAstStatCall(ident, call);
}
bool CAstArrayDesignator::TypeCheck(CToken *t, string *msg) const
{
bool result = true;
assert(_done);
if(!GetType()) { // if GetType is NULL then it is an invalid array expression
if(t != NULL) *t = GetToken();
if(msg != NULL) *msg = "invalid array expression.";
return false;
}
int i;
for(i = 0; i < GetNIndices(); i++) {
CAstExpression *e = GetIndex(i);
if(!e->TypeCheck(t, msg)) return false; // Do TypeCheck on indexing expression
if(!e->GetType()->IsInt()) { // The indexing expression should be Int type
if(t != NULL) *t = e->GetToken();
if(msg != NULL) *msg = "invalid array index expression.";
return false;
}
}
return result;
}
bool CAstStatIf::TypeCheck(CToken *t, string *msg) const
{
CAstExpression *cond = GetCondition();
bool result = true;
if (!cond->TypeCheck(t, msg)) return false;
if (cond->GetType() != CTypeManager::Get()->GetBool()) {
if (t != NULL) *t = cond->GetToken();
if (msg != NULL) *msg = "boolean expression expected.";
return false;
}
try {
CAstStatement *ifBody = GetIfBody();
CAstStatement *elseBody = GetElseBody();
while (result && (ifBody != NULL)) {
result = ifBody->TypeCheck(t, msg);
ifBody = ifBody->GetNext();
}
while (result && (elseBody != NULL)) {
result = elseBody->TypeCheck(t, msg);
elseBody = elseBody->GetNext();
}
} catch (...) {
result = false;
}
return result;
}
bool CAstFunctionCall::TypeCheck(CToken *t, string *msg) const
{
const CSymProc *symbol = GetSymbol();
// check the number of procedure/function arguments.
if (GetNArgs() != symbol->GetNParams()) {
if (t != NULL) *t = GetToken();
if (msg != NULL) *msg = "the number of arguments mismatch.";
return false;
}
// first, type check for expression of arguments.
// then, check the types of procedure/function arguments.
// in this project, arguments type is only integer.
for (int i = 0; i < GetNArgs(); i++) {
CAstExpression *arg = GetArg(i);
if (!arg->TypeCheck(t, msg)) return false;
if (arg->GetType() != symbol->GetParam(i)->GetDataType()) {
if (t != NULL) *t = arg->GetToken();
if (msg != NULL) *msg = "the type of arguments mismatch.";
return false;
}
}
return true;
}
bool CAstStatAssign::TypeCheck(CToken *t, string *msg) const
{
CAstDesignator *id = GetLHS();
CAstExpression *e = GetRHS();
if (!id->TypeCheck(t, msg)) return false;
if (!e->TypeCheck(t, msg)) return false;
if (!id->GetType()->Match(e->GetType())) {
if (t != NULL) *t = e->GetToken();
if (msg != NULL) *msg = "assignment type mismatch.";
return false;
}
return true;
}
CAstExpression* CParser::factor(CAstScope *s) {
//
// factor ::= qualident | number | boolean | char | string | "(" expression ")" | subroutineCall | "!" factor.
// FIRST(factor) = { tIdent, tNumber, tTrue, tFalse, tCharacter, tString, tLBrak, tEMark }.
//
CToken t;
EToken tt = _scanner->Peek().GetType();
CTypeManager *tm = CTypeManager::Get();
CAstExpression *n = NULL;
CSymtab *symtab = s->GetSymbolTable();
switch(tt) {
case tTrue:
Consume(tTrue, &t);
n = new CAstConstant(t, tm->GetBool(), 1);
break;
case tFalse:
Consume(tFalse, &t);
n = new CAstConstant(t, tm->GetBool(), 0);
break;
case tNumber:
{
Consume(tNumber, &t);
errno = 0;
long long v = strtoll(t.GetValue().c_str(), NULL, 10);
if (errno != 0) SetError(t, "invalid number.");
// integer range validation check.
if(v > 2147483648)
SetError(t, "integer constant outside valid range.");
n = new CAstConstant(t, tm->GetInt(), v);
break;
}
case tIdent:
{
Consume(tIdent, &t);
if(_scanner->Peek().GetType() == tLBrak) { // subroutineCall
Consume(tLBrak);
CAstFunctionCall *f;
// If subroutineCall calls undefined procedure/function, then set error.
if(symtab->FindSymbol(t.GetValue(),sLocal) == NULL && symtab->FindSymbol(t.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)) == NULL)
SetError(t, "invalid procedure/function identifier.");
f = new CAstFunctionCall(t, dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)));
}
else if(symtab->FindSymbol(t.GetValue(), sLocal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)) == NULL)
SetError(t, "invalid procedure/function identifier.");
f = new CAstFunctionCall(t, dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)));
}
else
SetError(t, "undefined identifier.");
assert(f != NULL);
if(isExpr(_scanner->Peek())) {
CAstExpression *expr = expression(s);
assert(expr != NULL);
// If array, then addressed.
if(expr->GetType()->IsArray())
expr = new CAstSpecialOp(expr->GetToken(), opAddress, expr, NULL);
f->AddArg(expr);
while(_scanner->Peek().GetType() == tComma) {
Consume(tComma);
expr = expression(s);
assert(expr != NULL);
// If array, then addressed.
if(expr->GetType()->IsArray())
expr = new CAstSpecialOp(expr->GetToken(), opAddress, expr, NULL);
f->AddArg(expr);
}
}
Consume(tRBrak);
n = f;
}
else { // qualident
if(_scanner->Peek().GetType() == tLSBrak) { // It means array
CAstArrayDesignator *f;
if(symtab->FindSymbol(t.GetValue(), sLocal) == NULL && symtab->FindSymbol(t.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)) != NULL)
SetError(t, "designator expected.");
f = new CAstArrayDesignator(t, symtab->FindSymbol(t.GetValue(), sGlobal));
}
else if(symtab->FindSymbol(t.GetValue(), sLocal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)) != NULL)
SetError(t, "designator expected");
f = new CAstArrayDesignator(t, symtab->FindSymbol(t.GetValue(), sLocal));
}
else {
SetError(t, "undefined identifier.");
}
while(_scanner->Peek().GetType() == tLSBrak) {
Consume(tLSBrak);
CAstExpression *expr = expression(s);
assert(expr != NULL);
f->AddIndex(expr);
Consume(tRSBrak);
}
f->IndicesComplete();
n = f;
} // non-array case.
else {
if(symtab->FindSymbol(t.GetValue(), sLocal) == NULL && symtab->FindSymbol(t.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)) != NULL) {
SetError(t, "designator expected.");
}
n = new CAstDesignator(t, symtab->FindSymbol(t.GetValue(), sGlobal));
}
else if(symtab->FindSymbol(t.GetValue(), sLocal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)) != NULL) {
SetError(t, "designator expected.");
}
n = new CAstDesignator(t, symtab->FindSymbol(t.GetValue(), sLocal));
}
else
SetError(t, "undefined identifier.");
}
}
break;
}
case tString:
Consume(tString, &t);
n = new CAstStringConstant(t, t.GetValue(), s);
break;
case tCharacter:
{
Consume(tCharacter, &t);
char res;
// If character length is 0, it means character is '\0' because invalid character cases are handled in scanner.
if(t.GetValue().length() == 0)
res = '\0';
else if(t.GetValue().length() == 1) {
if(t.GetValue().at(0) != '\\')
res = t.GetValue().at(0);
else SetError(t, "wrong character");
}
// unescape.
else if(t.GetValue().length() == 2) {
if(t.GetValue().at(0) == '\\') {
if(t.GetValue().at(1) == 'n') {
res = '\n';
}
else if(t.GetValue().at(1) == 't') {
res = '\t';
}
else if(t.GetValue().at(1) == '"') {
res = '"';
}
else if(t.GetValue().at(1) == '\'') {
res = '\'';
}
else if(t.GetValue().at(1) == '\\') {
res = '\\';
}
else if(t.GetValue().at(1) == '0') {
res = '\0';
}
else
SetError(t, "wrong character");
}
}
else SetError(t, "wrong character");
n = new CAstConstant(t, tm->GetChar(), (long long)res);
break;
}
case tLBrak:
Consume(tLBrak);
n = expression(s);
Consume(tRBrak);
break;
case tEMark:
Consume(tEMark, &t);
n = new CAstUnaryOp(t, opNot, factor(s));
break;
default:
// cout << "got " << _scanner->Peek() << endl;
SetError(_scanner->Peek(), "factor expected.");
break;
}
return n;
}