[gnumeric] Parsing: Change x^y^z into x^(y^z).

[Morten Welinder <mortenw src gnome org>]

commit dc8ba63a5d66ff2f0dc62c07af0710d659b0f5fa
Author: Morten Welinder <terra gnome org>
Date:   Wed Jun 10 12:12:42 2009 -0400

    Parsing: Change x^y^z into x^(y^z).
---
 ChangeLog    |    5 +++++
 NEWS         |    1 +
 src/parser.y |    8 ++++++--
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3f722e0..522001b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2009-06-10  Morten Welinder  <terra gnome org>
+
+	* src/parser.y: Change x^y^z into x^(y^z) to indicate how we
+	parsed it.
+
 2009-06-09  Andreas J. Guelzow <aguelzow pyrshep ca>
 
 	* src/ranges.c (range_clip_to_finite): adjust limits and add 
diff --git a/NEWS b/NEWS
index 25ae6a9..f69a53e 100644
--- a/NEWS
+++ b/NEWS
@@ -31,6 +31,7 @@ Morten:
 	* Fix NPER problems.
 	* Implement new functions COT and ACOT.  [#585270]
 	* Fix GCD.  [#585271]
+	* Change x^y^z into x^(y^z) to indicate parsing.
 
 --------------------------------------------------------------------------
 Gnumeric 1.9.8
diff --git a/src/parser.y b/src/parser.y
index 42bcdaf..c311c74 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -605,13 +605,17 @@ exp:	  CONSTANT 	{ $$ = $1; }
 	| exp '/' exp	{ $$ = build_binop ($1, GNM_EXPR_OP_DIV,	$3); }
 	| exp '^' exp	{
 		GnmExpr *l = $1;
+		GnmExpr *r = $3;
 
-		/* See bug 115941 */
 		if (is_signed (l)) {
+			/* See bug 115941 */
 			l = build_unary_op (GNM_EXPR_OP_PAREN, l);
+		} else if (GNM_EXPR_GET_OPER (r) == GNM_EXPR_OP_EXP) {
+			/* Add ()s to x^y^z */
+			r = build_unary_op (GNM_EXPR_OP_PAREN, r);
 		}
 
-		$$ = build_binop (l, GNM_EXPR_OP_EXP, $3);
+		$$ = build_binop (l, GNM_EXPR_OP_EXP, r);
 	}
 	| exp '&' exp	{ $$ = build_binop ($1, GNM_EXPR_OP_CAT,	$3); }
 	| exp '=' exp	{ $$ = build_binop ($1, GNM_EXPR_OP_EQUAL,	$3); }