From: NeilBrown <neilb@suse.de>
Date: Sun, 21 Jul 2013 09:27:27 +0000 (+1000)
Subject: parsergen: allow "$void" to remove current type.
X-Git-Tag: draftparser
X-Git-Url: https://ocean-lang.org/code/?p=ocean;a=commitdiff_plain;h=6a0710bfe1622b5420ba53dca034ed18376b8740;hp=36adc544609b6144adefa0a000f77d2845b814e2

parsergen: allow "$void" to remove current type.

This allows return to the initial state where nonterminals
have no type.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index e821e2c..0099f57 100644
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -235,6 +235,12 @@ The data type name is simply stored and applied to the head of all
 subsequent productions.  It must be the name of a structure, so `$expr`
 maps to `struct expr`.
 
+Any productions given before the first data type will have no data type
+and can carry no information.  In order to allow other non-terminals to
+have no type, the data type `$void` can be given.  This does *not* mean
+that `struct void` will be used, but rather than no type will be
+associated with future non-terminals.
+
 The precedence line must contain a list of symbols - typically
 terminal symbols, but not necessarily.  It can only contain symbols
 that have not been seen yet, so precedence declaration must precede
@@ -282,6 +288,8 @@ production inherits from the last symbol which has a precedence.
 			assoc = Non;
 		else {
 			g->current_type = t.txt;
+			if (text_is(t.txt, "void"))
+				g->current_type.txt = NULL;
 			t = token_next(ts);
 			if (t.num != TK_newline) {
 				err = "Extra tokens after type name";