From d278ad3c861aaae05119f69a265ba3c7748ccc24 Mon Sep 17 00:00:00 2001 From: Robby Findler Date: Tue, 15 Dec 2009 16:57:37 +0000 Subject: [PATCH] added a clarification to the redex docs ala Carl's next post on icfp-test svn: r17308 --- collects/redex/redex.scrbl | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/collects/redex/redex.scrbl b/collects/redex/redex.scrbl index 29df93ff02..ca1681bdd8 100644 --- a/collects/redex/redex.scrbl +++ b/collects/redex/redex.scrbl @@ -202,7 +202,10 @@ match exactly, unless it is the name of a non-terminal in a relevant language or contains an underscore. If it is a non-terminal, it matches any of the right-hand -sides of that non-terminal. +sides of that non-terminal. If the non-terminal appears +twice in a single pattern, then the match is constrained +to expressions that are the same, unless the pattern is part +of a grammar, in which case there is no constraint. If the symbol is a non-terminal followed by an underscore, for example @tt{e_1}, it is implicitly the same as a name @pattern