From bfa50ae031d3bb244c4cd403c230b5e0c3ad55df Mon Sep 17 00:00:00 2001
From: Robby Findler <robby@racket-lang.org>
Date: Sat, 22 Oct 2005 03:14:58 +0000
Subject: [PATCH] fixed up doc.txt and added labels to the arithmetic.ss
 example

svn: r1127
---
 collects/reduction-semantics/doc.txt          | 12 +++--
 .../examples/arithmetic.ss                    | 45 ++++++++++---------
 2 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/collects/reduction-semantics/doc.txt b/collects/reduction-semantics/doc.txt
index 9a4eb197e8..5a19a8f94c 100644
--- a/collects/reduction-semantics/doc.txt
+++ b/collects/reduction-semantics/doc.txt
@@ -228,7 +228,7 @@ for two `term-let'-bound identifiers bound to lists of
 different lengths to appear together inside an ellipsis.
 
 > (reduction language pattern bodies ...)       SYNTAX
-> (reduction/name language pattern bodies ...)  SYNTAX
+
 This form defines a reduction. The first position must
 evaluate to a language defined by the `language' form. The
 pattern determines which terms this reductions apply to and
@@ -261,12 +261,14 @@ the result of evaluating the last argument to reduction.
 See `plug' below and lc-subst is defined by using the 
 subst.ss library below.
 
+> (reduction/name name language pattern bodies ...)  SYNTAX
+
 The reduction/name form is the same as reduction, but
 additionally evaluates the `name' expression and names the
-reduction to be its result, which must be a string.
+reduction to be its result, which must be a string. The 
+names are used by `traces'.
 
 > (reduction/context language context pattern bodies ...)   SYNTAX
-> (reduction/context/name name language context pattern bodies ...) SYNTAX
 
 reduction/context is a short-hand form of reduction. It
 automatically adds the `in-hole' pattern and the call to
@@ -281,9 +283,13 @@ example is this:
                 (term (v_i ...))
                 (term e_body))))
 
+> (reduction/context/name name language context pattern bodies ...) SYNTAX
+
 reduction/context/name is the same as reduction/context, but
 additionally evaluates the `name' expression and names the
 reduction to be its result, which must be a string.
+The names are used by `traces'.
+
 
 > red? : (any? . -> . boolean?)
 
diff --git a/collects/reduction-semantics/examples/arithmetic.ss b/collects/reduction-semantics/examples/arithmetic.ss
index 9d617c9579..5515375934 100644
--- a/collects/reduction-semantics/examples/arithmetic.ss
+++ b/collects/reduction-semantics/examples/arithmetic.ss
@@ -12,33 +12,36 @@
             *
             /)
      
-     (e-ctxt (binop e e-ctxt)
+     (e-ctxt (binop v e-ctxt)
              (binop e-ctxt e)
              (sqrt e-ctxt)
              hole)
      (v number)))
   
+  (define-syntax (--> stx)
+    (syntax-case stx ()
+      [(_ op from to)
+       (syntax (reduction/name op
+                               lang
+                               (in-hole e-ctxt_1 from)
+                               (term (in-hole e-ctxt_1 ,to))))]))
+  
   (define reductions
     (list
-     (reduction lang
-                (in-hole e-ctxt_1
-                         (+ number_1 number_2))
-                (plug (term e-ctxt_1) (+ (term number_1) (term number_2))))
-     (reduction/context lang
-                        e-ctxt
-                        (- number_1 number_2)
-                        (- (term number_1) (term number_2)))
-     (reduction/context lang
-                        e-ctxt
-                        (* number_1 number_2)
-                        (* (term number_1) (term number_2)))
-     (reduction/context lang
-                        e-ctxt
-                        (/ number_1 number_2)
-                        (/ (term number_1) (term number_2)))
-     (reduction/context lang
-                        e-ctxt
-                        (sqrt number_1)
-                        (sqrt (term number_1)))))
+     (--> "add"
+          (+ number_1 number_2)
+          (+ (term number_1) (term number_2)))
+     (--> "subtract"
+          (- number_1 number_2)
+          (- (term number_1) (term number_2)))
+     (--> "multiply"
+          (* number_1 number_2)
+          (* (term number_1) (term number_2)))
+     (--> "divide"
+          (/ number_1 number_2)
+          (/ (term number_1) (term number_2)))
+     (--> "sqrt"
+          (sqrt number_1)
+          (sqrt (term number_1)))))
      
   (traces lang reductions '(- (* (sqrt 36) (/ 1 2)) (+ 1 2))))
\ No newline at end of file