// + && -
static TreeNode *
_simple_exp(void) {
TreeNode *t = _term();
while (token == PLUS || token == MINUS) {
TreeNode *q = new_exp_node(OpK);
q->child[0] = t;
q->attr.op = token;
t = q;
_match(token);
t->child[1] = _term();
}
return t;
}
static struct rx_node *_closure_term(struct parse_sp *ps)
{
struct rx_node *l, *n;
if (!(l = _term(ps)))
return NULL;
for (;;) {
switch (ps->type) {
case '*':
n = _node(ps->mem, STAR, l, NULL);
break;
case '+':
n = _node(ps->mem, PLUS, l, NULL);
break;
case '?':
n = _node(ps->mem, QUEST, l, NULL);
break;
default:
return l;
}
if (!n)
return_NULL;
_rx_get_token(ps);
l = n;
}
return n;
}
int value(void * bp, int get(void * bp), int unget(int c, void * bp))
{
extern signed c;
int n = _term(bp, get, unget);
while ((c = get(bp)) != EOF)
{
if (isblank(c)) continue;
else if(c == '+') n += _term(bp, get, unget);
else if(c == '-') n -= _term(bp, get, unget);
else
{
unget (c, bp);
break;
}
}
return (n);
}
int Parser::_expr()
{
int value = _term();
TokenType t = _token();
while (_success && (t == TT_PLUS || t == TT_MINUS)) {
_scanner.advance();
switch (t) {
case TT_PLUS: value += _term(); break;
case TT_MINUS: value -= _term(); break;
default:
notifyListeners("ERROR: Unknown error");
_success = false;
return 0;
}
t = _token();
}
return value;
}
double WidgetCalc::_expr(const std::string& str, unsigned *idx)
{
double result = _term(str, idx);
while (str[*idx] == '+' || str[*idx] == '-')
{
switch (str[*idx])
{
case '+':
++*idx;
result += _term(str, idx);
break;
case '-':
++*idx;
result -= _term(str, idx);
break;
}
}
return result;
}
RegNodePtr _repeat()
{
auto r = _term();
if (tryConsume('+')) {
r.reset(new RegNode_Repeat(r, 1, RegNode_Repeat::MAX_REPEAT));
}
else if (tryConsume('*')) {
r.reset(new RegNode_Repeat(r, 0, RegNode_Repeat::MAX_REPEAT));
}
else if (tryConsume('?')) {
r.reset(new RegNode_Repeat(r, 0, 1));
}
else {}
return r;
}