From ac4d39f9db28743b6c1e9def7a61241a50b02335 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Sun, 28 Mar 2004 21:15:01 +0000
Subject: * Added an operator `?' to test for attribute existence, e.g.,  
 `attrs ? x' yields true iff `attrs' has an attribute named `x'.

---
 src/libexpr/parser.y | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'src/libexpr/parser.y')

diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index b1fe9e093145..cfcbc589f61c 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -44,6 +44,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, void * data, char * s)
 %nonassoc EQ NEQ
 %right UPDATE
 %left NEG
+%nonassoc '?'
 %nonassoc '~'
 
 %%
@@ -81,6 +82,7 @@ expr_op
   | expr_op IMPL expr_op { $$ = ATmake("OpImpl(<term>, <term>)", $1, $3); }
   | expr_op UPDATE expr_op { $$ = ATmake("OpUpdate(<term>, <term>)", $1, $3); }
   | expr_op '~' expr_op { $$ = ATmake("SubPath(<term>, <term>)", $1, $3); }
+  | expr_op '?' ID { $$ = ATmake("OpHasAttr(<term>, <term>)", $1, $3); }
   | expr_app
   ;
 
-- 
cgit 1.4.1