From: NeilBrown <neil@brown.name>
Date: Mon, 19 Feb 2018 05:31:14 +0000 (+1100)
Subject: parsergen: be careful shifting TK_error
X-Git-Tag: StoneyCreek~8
X-Git-Url: https://ocean-lang.org/code/?p=ocean;a=commitdiff_plain;h=d28c54dc30f0b4322ffb2ecbbfcee9a566052d4b

parsergen: be careful shifting TK_error

shift() behaved a little differently when p.tos == 0,
and if the stack is completely empty, there is little
point trying to shift TK_error as there is no state
to work with.

So rearrange the loop slightly.

Signed-off-by: NeilBrown <neil@brown.name>
---

diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index 905e8f8..c25a87e 100644
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -2841,9 +2841,9 @@ one symbol for each line where newlines are allowed.
 			short indents = 0, start_of_line;
 
 			err_tk = tok_copy(*tk);
-			while (shift(&p, TK_error, 0, 0,
-			             err_tk, states) == 0
-			       && p.tos > 0)
+			while (p.tos > 0 &&
+			       shift(&p, TK_error, 0, 0,
+			             err_tk, states) == 0)
 				// discard this state
 				indents += pop(&p, 1, &start_of_line, do_free);
 			if (p.tos == 0) {