value passthrough about packcc

[arithy]

Let me rewrite your expressions more precisely.
The rule definition way you want:
expression <- x:( rule_a / rule_b / rule_c / rule_d ) { $$ = x; }
The currently valid definition way:
expression <- a:rule_a { $$ = a; } / b:rule_b { $$ = b; } / c:rule_c { $$ = c; } / d:rule_d { $$ = d; }

If the syntax is limited to the manner below:
variable : ( rulename / rulename / ... )

• only rule names exist in the parentheses,
• rule names can be combined using only / operator, and
• every rule name cannot have a respective prefixed variable,

it may be possible to realize this, but I cannot promise to do it soon.
I'll try to implement it whenever I have time.

[0alfa]

this macro works for now

#define PT                                                                     \
  pcc_value_refer_table_t _x = __pcc_in->data.leaf.values;                     \
  i(_x.len, I(_x.buf[i] && *_x.buf[i], NODE *n = ((NODE *)*_x.buf[i]);         \
              __ = *_x.buf[i]))

value <- (a:funclit / a:term) { PT; }

expands to

static void pcc_action_value_0(pcc_context_t *__pcc_ctx, pcc_thunk_t *__pcc_in,
                               pcc_value_t *__pcc_out) {
  pcc_value_refer_table_t _x = __pcc_in->data.leaf.values;
  for (size_t i = 0; i < _x.len; i++) {
    if (_x.buf[i] && *_x.buf[i]) {
      NODE *n = ((NODE *)*_x.buf[i]);
      (*__pcc_out) = *_x.buf[i];
    };
  };
}

[awrc]

I've found that this works

expression <- (x:a / x:b / x:c / x:d) { $$ = x; }

[arithy]

@awrc , thank you for the helpful comment!
@0alfa , please use the syntax above. I'd like to close this issue as "not planned".