From patchwork Fri Sep 10 23:19:21 2010
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Subject: [gccgo] Permit omitting lower bound in a slice expression
Date: Fri, 10 Sep 2010 13:19:21 -0000
From: Ian Taylor <iant@google.com>
X-Patchwork-Id: 64477
Message-Id: <mcrd3sl89vq.fsf@google.com>
To: gcc-patches@gcc.gnu.org, gofrontend-dev@googlegroups.com

The Go language was tweaked to permit omitting the lower bound in a
slice expression.  This patch implements that for gccgo.  Committed to
gccgo branch.

Ian


diff -r f46918ae9445 go/parse.cc
--- a/go/parse.cc	Fri Sep 10 11:41:29 2010 -0700
+++ b/go/parse.cc	Fri Sep 10 16:17:39 2010 -0700
@@ -2653,8 +2653,10 @@
     start = this->expression(PRECEDENCE_NORMAL, false, true, NULL);
   else
     {
-      this->error("missing lower bound in slice expression");
-      start = Expression::make_error(this->location());
+      mpz_t zero;
+      mpz_init_set_ui(zero, 0);
+      start = Expression::make_integer(&zero, NULL, location);
+      mpz_clear(zero);
     }
 
   Expression* end = NULL;