/* Operators: ==, != (left-associative) */
static ASTNode *parse_comparison(Parser *p)
{
ASTNode *expr = parse_relational(p);
loop:
switch (peek_id(p)) {
case TOK_EQUAL: /* == */
accept(p); ignore_eols(p);
expr = ast_create_2(AST_IS_EQUAL, expr, parse_comparison(p));
goto loop;
case TOK_NOT_EQUAL: /* != */
accept(p); ignore_eols(p);
expr = ast_create_2(AST_IS_NOT_EQUAL, expr, parse_comparison(p));
goto loop;
}
return expr;
}
/* Parse a primary-expression string in *P.
On success, return the parsed primary-expression.
On error, set *P->ERROR to an error string (for free()) or NULL, and return
NULL. */
static struct expr *
parse_primary(struct parsing *p)
{
struct expr *e;
switch (p->token) {
case EO_NOT: {
struct expr *res;
if (lex(p) != 0)
return NULL;
e = parse_primary(p);
if (e == NULL)
return NULL;
res = parser_malloc(p, sizeof(*res));
if (res == NULL)
goto err_e;
res->op = EO_NOT;
res->v.sub[0] = e;
return res;
}
case T_LEFT_PAREN: {
if (lex(p) != 0)
return NULL;
e = parse_or(p);
if (e == NULL)
return NULL;
if (p->token != T_RIGHT_PAREN) {
*p->error = NULL;
asprintf(p->error, "Right paren expected, got `%.*s'",
p->token_len, p->token_start);
goto err_e;
}
if (lex(p) != 0)
goto err_e;
return e;
}
case T_FIELD_ESCAPE: case T_STRING:
return parse_comparison(p);
default:
*p->error = NULL;
asprintf(p->error, "Unexpected token `%.*s'", p->token_len,
p->token_start);
return NULL;
}
abort(); /* Should never get here */
err_e:
expr_free(e);
return NULL;
}
/* Operators: =, +=, -=, /=, *= (right-associative) */
static ASTNode *parse_assign(Parser *p)
{
ASTNode *expr = parse_comparison(p);
switch (peek_id(p)) {
case TOK_ASSIGN:
accept(p); ignore_eols(p);
expr = ast_create_2(AST_ASSIGN, expr, parse_assign(p));
break;
}
return expr;
}