/**
* parse expression
*/
expr_t parse_expr(tokenizer_t t){
expr_t expr_left, expr_right;
expr_left = parse_eq_expr(t);
struct token tok = cur_tok(t);
if(tok.kind == TOK_ASSIGN){
eat_it(t, TOK_ASSIGN);
expr_right = parse_expr(t);
expr_t assign_expr = mk_expr_bin_op(t->filename, t->line, op_kind_assign, expr_left, expr_right);
return assign_expr;
}else{
// これは式文
return expr_left;
}
}
// log_and_expr := log_and_expr && equality_expr
// equality_expr
//
// log_and_expr := equality_expr (log_and_expr)
Expr*
parse_log_and_expr(Parser& p, Token_stream& ts)
{
if (Expr* e1 = parse_eq_expr(p, ts)) {
if (Token const* tok = ts.next()) {
switch (tok->kind()) {
// advance past the operator and move to parse the 'rest' of the expr
case log_and_tok:
return parse_log_and_rest(p, ts, ts.advance(), e1);
default:
return e1;
}
}
return e1;
}
return nullptr;
}
// log_and_rest := ... && equality_expr (log_and_rest)
Expr*
parse_log_and_rest(Parser& p, Token_stream& ts, Token const* tok, Expr* e1)
{
if (Expr* e2 = parse_eq_expr(p, ts)) {
if (Token const* t = ts.next()) {
// keep parsing the 'rest' while we still have a valid operator
if (t->kind() == log_and_tok)
return parse_log_and_rest(p, ts, ts.advance(), p.on_binary(tok, e1, e2));
else
return p.on_binary(tok, e1, e2);
}
return p.on_binary(tok, e1, e2);
}
error("Expected expression after logical-or expr: ");
print(e1);
print(tok);
print("\n");
return nullptr;
}
