From dd18cc837f3bfe63e7cf65ca68375692e807e411 Mon Sep 17 00:00:00 2001 From: Robby Findler Date: Tue, 15 Dec 2009 16:41:55 +0000 Subject: [PATCH] added a clarification to the redex docs ala Carl's post on icfp-test svn: r17307 --- collects/redex/redex.scrbl | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/collects/redex/redex.scrbl b/collects/redex/redex.scrbl index 7d99f20667..29df93ff02 100644 --- a/collects/redex/redex.scrbl +++ b/collects/redex/redex.scrbl @@ -700,18 +700,19 @@ The fresh variables clause generates variables that do not occur in the term being matched. If the @scheme[fresh-clause] is a variable, that variable is used both as a binding in the rhs-exp and as the prefix for the freshly generated -variable. +variable. (The variable does not have to be +a non-terminal in the language of the reduction relation.) The second case of a @scheme[fresh-clause] is used when you want to generate a sequence of variables. In that case, the ellipses are literal ellipses; that is, you must actually write -ellipses in your rule. The variable var1 is like the +ellipses in your rule. The variable @scheme[var1] is like the variable in first case of a @scheme[fresh-clause], namely it is used to determine the prefix of the generated variables and it is bound in the right-hand side of the reduction rule, but unlike the single-variable fresh clause, it is bound to -a sequence of variables. The variable var2 is used to -determine the number of variables generated and var2 must be +a sequence of variables. The variable @scheme[var2] is used to +determine the number of variables generated and @scheme[var2] must be bound by the left-hand side of the rule. The side-conditions are expected to all hold, and have the