Function parse_branch

compat/regex/regcomp.c:2192–2224

}

/* This function build the following tree, from regular expression
   <exp1><exp2>:
	CAT
	/ \
       /   \
   <exp1> <exp2>

   CAT means concatenation.  */

static bin_tree_t *
parse_branch (re_string_t *regexp, regex_t *preg, re_token_t *token,
	      reg_syntax_t syntax, int nest, reg_errcode_t *err)
{
  bin_tree_t *tree, *exp;
  re_dfa_t *dfa = (re_dfa_t *) preg->buffer;
  tree = parse_expression (regexp, preg, token, syntax, nest, err);
  if (BE (*err != REG_NOERROR && tree == NULL, 0))
    return NULL;

  while (token->type != OP_ALT && token->type != END_OF_RE
	 && (nest == 0 || token->type != OP_CLOSE_SUBEXP))
    {
      exp = parse_expression (regexp, preg, token, syntax, nest, err);
      if (BE (*err != REG_NOERROR && exp == NULL, 0))
	{
	  return NULL;
	}
      if (tree != NULL && exp != NULL)
	{
	  tree = create_tree (dfa, tree, exp, CONCAT);
	  if (tree == NULL)
	    {
	      *err = REG_ESPACE;
	      return NULL;
	    }
	}