Improve hash-ref! shortcuts

default-recommendations/hash-shortcuts-test.rkt

@@ -54,7 +54,7 @@ test: "hash-ref! with non-constant lambda cannot be simplified to hash-ref! with
 ------------------------------
 
 
-test: "hash-ref with hash-set! lambda can be simplified to hash-ref!"
+test: "hash-ref with hash-set! can be simplified to hash-ref!"
 ------------------------------
 (define h (make-hash))
 (define k 'a)
@@ -66,11 +66,19 @@ test: "hash-ref with hash-set! lambda can be simplified to hash-ref!"
 ------------------------------
 (define h (make-hash))
 (define k 'a)
+(or (hash-ref h k #false)
+    (let ([v (+ 1 2 3)])
+      (hash-set! h k v)
+      v))
+------------------------------
+------------------------------
+(define h (make-hash))
+(define k 'a)
 (hash-ref! h k (λ () (+ 1 2 3)))
 ------------------------------
 
 
-test: "hash-ref with hash-set! lambda and literal keys can be simplified to hash-ref!"
+test: "hash-ref with hash-set! and literal keys can be simplified to hash-ref!"
 ------------------------------
 (define h (make-hash))
 (hash-ref h 'a (λ ()
@@ -80,6 +88,13 @@ test: "hash-ref with hash-set! lambda and literal keys can be simplified to hash
 ------------------------------
 ------------------------------
 (define h (make-hash))
+(or (hash-ref h 'a #false)
+    (let ([v (+ 1 2 3)])
+      (hash-set! h 'a v)
+      v))
+------------------------------
+------------------------------
+(define h (make-hash))
 (hash-ref! h 'a (λ () (+ 1 2 3)))
 ------------------------------
 

default-recommendations/hash-shortcuts.rkt

@@ -82,6 +82,20 @@
    (hash-ref! h1 k1 v1)])
 
 
+(define-refactoring-rule or-hash-ref-set!-to-hash-ref!
+  #:description "This expression can be replaced with a simpler, equivalent `hash-ref!` expression."
+  #:literals (or hash-ref hash-set! let)
+  [(or (hash-ref h1:id k1:pure-expression #false)
+       (let ([v1:id initializer:value-initializer])
+         (hash-set! h2:id k2:pure-expression v2:id)
+         v3:id))
+   #:when (free-identifier=? #'h1 #'h2)
+   #:when (syntax-free-identifier=? #'k1 #'k2)
+   #:when (free-identifier=? #'v1 #'v2)
+   #:when (free-identifier=? #'v1 #'v3)
+   (hash-ref! h1 k1 initializer.failure-result-form)])
+
+
 (define-refactoring-rule hash-set!-ref-to-hash-update!
   #:description
   "This expression can be replaced with a simpler, equivalent `hash-update!` expression."
@@ -124,4 +138,5 @@
                  hash-ref-set!-with-constant-to-hash-ref!
                  hash-ref-with-constant-lambda-to-hash-ref-without-lambda
                  hash-ref!-with-constant-lambda-to-hash-ref!-without-lambda
-                 hash-set!-ref-to-hash-update!)))
+                 hash-set!-ref-to-hash-update!
+                 or-hash-ref-set!-to-hash-ref!)))