From b1c7707fcbfebd67ad2913fe96a27c73e4104af5 Mon Sep 17 00:00:00 2001
From: Will Coleda <will@coleda.com>
Date: Fri, 4 Dec 2009 15:39:57 -0500
Subject: [PATCH] empty expression should error.

---
 TODO                        |  6 ------
 src/Partcl/commands/main.pm | 28 ++++++++++++++++------------
 2 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/TODO b/TODO
index 8e71fbc..cbd5ee4 100644
--- a/TODO
+++ b/TODO
@@ -4,12 +4,6 @@ Big Goals
 
 Tasks/Bugs:
 
-* empty expr should die:
-
-% expr ""
-empty expression
-in expression ""
-
 * regexp $re $str (blocker for t/tcl_time.t)
 * regsub -all <exp> <string> <replace>
 * Need to throw an exception when trying to convert something to an
diff --git a/src/Partcl/commands/main.pm b/src/Partcl/commands/main.pm
index 0cfc691..2c31975 100644
--- a/src/Partcl/commands/main.pm
+++ b/src/Partcl/commands/main.pm
@@ -118,19 +118,23 @@ our sub exit(*@args) {
 
 our sub expr(*@args) { 
     my $code := pir::join(' ', @args);
-    our %EXPRCACHE;
-    my &sub := %EXPRCACHE{$code};
-    unless pir::defined__IP(&sub) {
-        my $parse := 
-            Partcl::Grammar.parse(
-                $code,
-                :rule('TOP_expr'),
-                :actions(Partcl::Actions) 
-            );
-        &sub := PAST::Compiler.compile($parse.ast);
-        %EXPRCACHE{$code} := &sub;
+    if $code ne '' {
+        our %EXPRCACHE;
+        my &sub := %EXPRCACHE{$code};
+        unless pir::defined__IP(&sub) {
+            my $parse := 
+                Partcl::Grammar.parse(
+                    $code,
+                    :rule('TOP_expr'),
+                    :actions(Partcl::Actions) 
+                );
+            &sub := PAST::Compiler.compile($parse.ast);
+            %EXPRCACHE{$code} := &sub;
+        }
+        &sub();
+    } else {
+        error("empty expression\nin expression \"\"");
     }
-    &sub();
 }
 
 our sub for(*@args) {