compilerCode-/parser.c at master · YaseenKaraki/compilerCode- · GitHub

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#include "global.h"

int lookahead;
parse() /* parses and translates expression list */
{
    lookahead = lexan();
    while (lookahead != DONE) {
        expr(); match(';');
    }
}

expr()
{
    int t;
    term();
    while (1)
        switch (lookahead) {
        case '+': case '-':
            t = lookahead;
            match(lookahead); term(); emit(t, NONE);
            continue;
        default:
            return;
        }
}
term()
{
    int t;
    factor();
    while (1)
        switch (lookahead) {
        case '*': case '/': case DIV: case MOD:
            t = lookahead;
            match(lookahead); factor(); emit(t, NONE);
            continue;
        default:
            return;
        }
}

factor()
{
    switch (lookahead) {
    case '(':
        match('('); expr(); match(')'); break;
    case NUM:
        emit(NUM, tokenval); match(NUM); break;
    case ID:
        emit(ID, tokenval); match(ID); break;
    default:
        error("syntax error");
    }

}

match(t)
int t;
{
    if (lookahead == t)
        lookahead = lexan();
    else error("syntax error");
}