constant_t node_add_eval(node_t*n, environment_t* env)
{
double sum = 0;
int t;
for(t=0;t<n->num_children;t++) {
sum += AS_FLOAT(EVAL_CHILD(t));
}
return float_constant(sum);
}
constant_t node_sub_eval(node_t*n, environment_t* env)
{
constant_t left = EVAL_CHILD(0);
constant_t right = EVAL_CHILD(1);
return float_constant(AS_FLOAT(left) - AS_FLOAT(right));
}
//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);
}
}
}
