From b74ad87160697a8cca92401d1d048ae307b20fd0 Mon Sep 17 00:00:00 2001
From: Jon Rafkind <rafkind@racket-lang.org>
Date: Wed, 1 Feb 2012 14:45:30 -0700
Subject: [PATCH] [honu] wrap the condition of when expression inside
 parentheses. instantiate literal sets at the proper phase for honu macros

---
 collects/honu/core/private/honu2.rkt  |  2 +-
 collects/honu/core/private/macro2.rkt | 19 +++++++++++--------
 collects/honu/private/common.honu     |  4 ++--
 collects/tests/honu/check.rkt         |  2 +-
 4 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/collects/honu/core/private/honu2.rkt b/collects/honu/core/private/honu2.rkt
index 33f3605ca6..c03c06e7ac 100644
--- a/collects/honu/core/private/honu2.rkt
+++ b/collects/honu/core/private/honu2.rkt
@@ -68,7 +68,7 @@
   (lambda (code context)
     (syntax-parse code #:literal-sets (cruft)
                        #:literals (else honu-then)
-      [(_ condition:honu-expression honu-then true:honu-expression (~optional else) false:honu-expression . rest)
+      [(_ (#%parens condition:honu-expression) true:honu-expression (~optional else) false:honu-expression . rest)
        (values
          #'(%racket (if condition.result true.result false.result))
          #'rest
diff --git a/collects/honu/core/private/macro2.rkt b/collects/honu/core/private/macro2.rkt
index eb8bc1bbb2..a4e9ce98a0 100644
--- a/collects/honu/core/private/macro2.rkt
+++ b/collects/honu/core/private/macro2.rkt
@@ -22,23 +22,25 @@
   (define-splicing-syntax-class pattern-type
     #:literal-sets (cruft)
     [pattern (~seq name colon class)
-             #:with result #'(~var name class #:attr-name-separator "_")]
-    [pattern x #:with result #'x])
+             #:with (result ...) #'((~var name class #:attr-name-separator "_"))]
+    [pattern (x:pattern-type ...) #:with (result ...) #'((x.result ... ...))]
+    [pattern x #:with (result ...) #'(x)])
   (syntax-parse original-pattern
     [(thing:pattern-type ...)
-     #'(thing.result ...)]))
+     #'(thing.result ... ...)]))
 
 (define-for-syntax (find-pattern-variables original-pattern)
   (define-splicing-syntax-class pattern-type
     #:literal-sets (cruft)
     [pattern (~seq name colon class)
              ;; we know the output of syntactic classes will end with _result
-             #:with result (with-syntax ([name.result (format-id #'name "~a_result" #'name)])
-                             #'(name name.result))]
-    [pattern x #:with result #f])
+             #:with (result ...) (with-syntax ([name.result (format-id #'name "~a_result" #'name)])
+                             #'((name name.result)))]
+    [pattern (x:pattern-type ...) #:with (result ...) #'(x.result ... ...)]
+    [pattern x #:with (result ...) #'()])
   (syntax-parse original-pattern
     [(thing:pattern-type ...)
-     (filter (lambda (x) (syntax-e x)) (syntax->list #'(thing.result ...)))]))
+     (filter (lambda (x) (syntax-e x)) (syntax->list #'(thing.result ... ...)))]))
 
 (begin-for-syntax
 (define-syntax (parse-stuff stx)
@@ -63,7 +65,8 @@
                         (lambda (stx context-name)
                           (define-literal-set local-literals (literal ...))
                           (syntax-parse stx
-                            #:literal-sets (cruft local-literals)
+                            #:literal-sets ([cruft #:at name]
+                                            [local-literals #:at name])
                             [(_ syntax-parse-pattern ... . more)
                              (values
                                ;; if the pattern is x:expression then x_result will
diff --git a/collects/honu/private/common.honu b/collects/honu/private/common.honu
index 9e44088e45..0a62ee1579 100644
--- a/collects/honu/private/common.honu
+++ b/collects/honu/private/common.honu
@@ -1,8 +1,8 @@
 #lang honu/core
 
 provide when;
-macro when (then){ condition:expression then body:expression }{
-  syntax(if condition then body else { void() })
+macro when (){ (condition:expression) body:expression }{
+  syntax(if (condition) body else { })
 }
 
 /*
diff --git a/collects/tests/honu/check.rkt b/collects/tests/honu/check.rkt
index 99040a0d05..7ee0fc00fd 100644
--- a/collects/tests/honu/check.rkt
+++ b/collects/tests/honu/check.rkt
@@ -104,7 +104,7 @@
 (test
   "if"
   @input{
-  if 2 > 1 then
+  if (2 > 1)
     1
   else
     0