ONIG_SYN_OP_ESC_VBAR_ALT 3218 regparse.c           if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_VBAR_ALT)) break;
ONIG_SYN_OP_ESC_VBAR_ALT   89 regsyntax.c        ONIG_SYN_OP_ESC_LPAREN_SUBEXP | ONIG_SYN_OP_ESC_VBAR_ALT |
ONIG_SYN_OP_ESC_VBAR_ALT  110 regsyntax.c        ONIG_SYN_OP_ESC_VBAR_ALT |