Improve throw-unless-truthy-to-or formatting (#463)

Author: jackfirth

default-recommendations/conditional-shortcuts-test.rkt

@@ -427,6 +427,41 @@ test: "always-throwing unless before returning condition variable refactorable t
 --------------------
 
 
+test: "refactoring always-throwing unless to or doesn't reformat surrounding context"
+--------------------
+(define (f s)
+
+  ( define foo 42 )
+  
+  (define x (string->number s))
+  (unless x
+    (error "string that is not a num"))
+  x)
+--------------------
+--------------------
+(define (f s)
+
+  ( define foo 42 )
+  
+  (or (string->number s) (error "string that is not a num")))
+--------------------
+
+
+test: "refactoring always-throwing unless to or can reformat when its the only body"
+--------------------
+(define (f s)
+  (λ (v)
+    (define x (string->number s))
+    (unless x
+      (error "string that is not a num"))
+    x))
+--------------------
+--------------------
+(define (f s)
+  (λ (v) (or (string->number s) (error "string that is not a num"))))
+--------------------
+
+
 test: "cond with nested else-cond can be flattened"
 ------------------------------
 (define (f a b)

default-recommendations/conditional-shortcuts.rkt

@@ -10,6 +10,7 @@
 
 
 (require (for-syntax racket/base)
+         racket/list
          resyntax/base
          resyntax/default-recommendations/private/boolean
          resyntax/default-recommendations/private/exception
@@ -156,11 +157,17 @@
         (~and def (define truthy-var:id truthy-expr))
         (~and check (unless truthy-var2:id fail:always-throwing-expression))
         truthy-var3:id)
+
   #:when (free-identifier=? #'truthy-var #'truthy-var2)
   #:when (free-identifier=? #'truthy-var #'truthy-var3)
-  (body-before ...
-   (~focus-replacement-on
-    (~replacement (or truthy-expr fail) #:original-splice (def check truthy-var3)))))
+  #:with or-expression
+  #'(~replacement (or truthy-expr fail) #:original-splice (def check truthy-var3))
+  #:with focused-or-expression
+  (if (empty? (attribute body-before))
+      #'or-expression
+      #'(~focus-replacement-on or-expression))
+
+  (body-before ... focused-or-expression))
 
 
 (define-refactoring-rule cond-else-cond-to-cond