Attribute* binary_operator( Attribute* attr1, Attribute* attr2, int op, int reverse, int rm1, int rm2, int lno) {
if(attr1==NULL || attr2==NULL)
die(lno, "NULL pointer for attr1 or attr2\n");
if(reverse) {
Attribute* tmp = attr1;
attr1 = attr2;
attr2 = tmp;
}
Attribute* result;
switch (op) {
case OP_ADD:
case OP_SUB:
case OP_MUL:
case OP_DIV:
result = math_operator(attr1, attr2, op, lno);break;
case OP_GT:
case OP_LT:
case OP_GE:
case OP_LE:
result = relational_operator(attr1, attr2, op, lno);break;
case OP_AND:
case OP_OR:
result = logic_operator(attr1, attr2, op, lno); break;
case OP_EQ:
case OP_NE:
result = equal_operator(attr1, attr2, op, lno); break;
default:
die(lno, "binary_opertor: unsupported OP %d.\n", op);
}
if(rm1==FLAG_DESTROY_ATTR) destroy_attr(attr1);
if(rm2==FLAG_DESTROY_ATTR) destroy_attr(attr2);
return result;
}
//main function
int main()
{
initialize_Symbol_Table();
remove("a4_1.out");
char input[1000];
token t;
int i;
//loop for rading lines of source code into input buffer
while(gets(input))
{
lexemeBegin = 0;
while(input[lexemeBegin]!='\0'&&input[lexemeBegin]!='\n' &&input[lexemeBegin]!='\r') //while end of line is not found
{
while(input[lexemeBegin]==' ' || input[lexemeBegin] == '\t')
lexemeBegin++;
//checking for keywords and identifiers
t = identifier_keyword(input);
if(t.tokenID!=NOTOK)
{
write_token(t);
continue;
}
//checking for integer constants
t = integer_constant(input);
if(t.tokenID!=NOTOK)
{
write_token(t);
continue;
}
//checking for floating point number constants
t = float_constant(input);
if(t.tokenID!=NOTOK)
{
write_token(t);
continue;
}
//checking for arithmetic operators
t = arithmetic_operator(input);
if(t.tokenID!=NOTOK)
{
write_token(t);
continue;
}
//checking for assignment operators
t = assignment_operator(input);
if(t.tokenID!=NOTOK)
{
write_token(t);
continue;
}
//checking for relational operators
t = relational_operator(input);
if(t.tokenID!=NOTOK)
{
write_token(t);
continue;
}
//checking for special symbols
t = special_symbol(input);
if(t.tokenID!=NOTOK)
{
write_token(t);
continue;
}
//checking for comments
comment(input);
//checking erroneous lexeme
error_condition(input);
}
}
}