/* FIRST(statement)={AVID,SVID,IF,USING,INPUT,OUTPUT}
<statement> ->
<assignment statement>
| <selection statement>
| <iteration statement>
| <input statement>
| <output statement>
Author: Kwok Hong Kelvin Chan */
void statement(void){
switch(lookahead_token.code){
case AVID_T:
case SVID_T:
assignment_statement();
break;
case KW_T:
switch(lookahead_token.attribute.get_int) {
case IF:
selection_statement();
break;
case USING:
iteration_statement();
break;
case INPUT:
input_statement();
break;
case OUTPUT:
output_statement();
break;
default:
syn_printe();
break;
}
break;
default:
syn_printe();
break;
}
}
/*
* Production: Statement
* FIRST set: { AVID_T, SVID_T, KW_T (only IF, USING, INPUT, OUTPUT) }
*/
void statement(void) {
switch (lookahead.code) {
case AVID_T:
case SVID_T:
assignment_statement();
return;
case KW_T:
/* The token attribute must be IF, INPut, OUTPUT or USING */
switch (lookahead.attribute.kwt_idx) {
case IF:
selection_statement();
return;
case INPUT:
input_statement();
return;
case OUTPUT:
output_statement();
return;
case USING:
iteration_statement();
return;
/* If the keyword token does not match the above, print an error and return. */
default:
syn_printe();
return;
}
/* If nothing matches, print an error. */
default:
syn_printe();
return;
}
}
void SyntaxAnalyzer::S()
{
if ((cur->type == keyword)&&
(strcmp(cur->lex, "end")!=0)) {
if (strcmp(cur->lex, "if")==0) {
next();
if_statement();
S();
}
else
if (strcmp(cur->lex, "while")==0) {
next();
while_statement();
S();
}
else
if (strcmp(cur->lex, "goto")==0) {
next();
goto_statement();
PolizOpGo* tmp = new PolizOpGo;
add_poliz_list(tmp);
S();
}
else
if (strcmp(cur->lex, "print")==0) {
next();
print_statement();
PolizPrint* tmp = new PolizPrint;
add_poliz_list(tmp);
S();
}
else
if (strcmp(cur->lex, "then")!=0) {
game_statement();
S();
}
else
throw Exeption("unexpected then", cur->num_str, cur->lex);
}
else
if (cur->type == variable) {
make_poliz_var();
next();
assignment_statement();
PolizFunAssign* tmp = new PolizFunAssign;
add_poliz_list(tmp);
S();
}
else
if (cur->type == label) {
make_poliz_label();
next();
if (strcmp(cur->lex, ">")!=0)
throw Exeption("'>' expected", cur->num_str, cur->lex);
next();
S();
}
else {
if (strcmp(cur->lex, "end")!=0)
throw Exeption("end expected", cur->num_str, cur->lex);
else
next();
}
}
