!293 Add rich-list%reduce-option in (liii lang)

GoldfishLang.tmu

@@ -3975,46 +3975,52 @@
 
   <section|高阶函数>
 
-  \;
-
-  <\scm-chunk|goldfish/liii/lang.scm|true|true>
-    \ \ (define (%map x . xs)
+  <paragraph|rich-list%map>
 
-    \ \ \ \ (let1 r (rich-list (map x data))
+  <\goldfish-chunk|goldfish/liii/lang.scm|true|true>
+    (chained-define (%map x)
 
-    \ \ \ \ \ \ (if (null? xs) r (apply r xs))))
+    \ \ (rich-list (map x data)))
 
-    \ \ 
+    \;
+  </goldfish-chunk>
 
-    \ \ (define (%flat-map x . xs)
+  <paragraph|rich-list%flat-map>
 
-    \ \ \ \ (let1 r (rich-list (flat-map x data))
+  <\goldfish-chunk|goldfish/liii/lang.scm|true|true>
+    (chained-define (%flat-map x)
 
-    \ \ \ \ \ \ (if (null? xs) r (apply r xs))))
+    \ \ (rich-list (flat-map x data)))
 
-    \ \ 
+    \;
+  </goldfish-chunk>
 
-    \ \ (define (%filter x . xs)
+  <paragraph|rich-list%filter>
 
-    \ \ \ \ (let1 r (rich-list (filter x data))
+  <\goldfish-chunk|goldfish/liii/lang.scm|true|true>
+    (chained-define (%filter x)
 
-    \ \ \ \ \ \ (if (null? xs) r (apply r xs))))
+    \ \ (rich-list (filter x data)))
 
     \;
+  </goldfish-chunk>
 
-    \ \ (define (%for-each x)
+  <paragraph|rich-list%for-each>
+
+  <\scm-chunk|goldfish/liii/lang.scm|true|true>
+    (define (%for-each x)
 
-    \ \ \ \ (for-each x data))
+    \ \ (for-each x data))
 
     \;
   </scm-chunk>
 
   <paragraph|rich-list%reverse>
 
   <\goldfish-chunk|goldfish/liii/lang.scm|true|true>
-    \ \ (chained-define (%reverse)
+    (chained-define (%reverse)
 
-    \ \ \ \ (rich-list (reverse data)))
+    \ \ (rich-list (reverse data)))
 
     \ \ \ \ 
   </goldfish-chunk>
@@ -4543,6 +4549,34 @@
     \;
   </goldfish-chunk>
 
+  <paragraph|rich-list%reduce-option>
+
+  <\goldfish-chunk|goldfish/liii/lang.scm|true|true>
+    (define (%reduce-option f)
+
+    \ \ (if (null? data)
+
+    \ \ \ \ \ \ (none)
+
+    \ \ \ \ \ \ (option (reduce f '() data))))
+
+    \;
+  </goldfish-chunk>
+
+  <\goldfish-chunk|tests/goldfish/liii/lang-test.scm|true|true>
+    (check ($ '() :reduce-option +) =\<gtr\> (none))
+
+    \;
+
+    (check ($ '(1 2 3) :reduce-option +) =\<gtr\> (option 6)) \ 
+
+    (check ($ '(2 3 4) :reduce-option *) =\<gtr\> (option 24)) \ 
+
+    (check ($ '(5) :reduce-option (lambda (x y) (+ x y 10))) =\<gtr\> (option 5))
+
+    \;
+  </goldfish-chunk>
+
   <section|转换器>
 
   <paragraph|rich-list%to-string>

goldfish/liii/lang.scm

@@ -768,23 +768,20 @@
 (define (%contains elem)
   (%exists (lambda (x) (equal? x elem))))
 
-  (define (%map x . xs)
-    (let1 r (rich-list (map x data))
-      (if (null? xs) r (apply r xs))))
-
-  (define (%flat-map x . xs)
-    (let1 r (rich-list (flat-map x data))
-      (if (null? xs) r (apply r xs))))
-
-  (define (%filter x . xs)
-    (let1 r (rich-list (filter x data))
-      (if (null? xs) r (apply r xs))))
+(chained-define (%map x)
+  (rich-list (map x data)))
 
-  (define (%for-each x)
-    (for-each x data))
+(chained-define (%flat-map x)
+  (rich-list (flat-map x data)))
+
+(chained-define (%filter x)
+  (rich-list (filter x data)))
+
+(define (%for-each x)
+  (for-each x data))
 
-  (chained-define (%reverse)
-    (rich-list (reverse data)))
+(chained-define (%reverse)
+  (rich-list (reverse data)))
 
   (define (%take x . xs)
     (typed-define (scala-take (data list?) (n integer?))
@@ -887,6 +884,11 @@
       (value-error "rich-list%reduce: empty list is not allowed to reduce")
       (reduce f '() data)))
 
+(define (%reduce-option f)
+  (if (null? data)
+      (none)
+      (option (reduce f '() data))))
+
 (define (%to-string)
   (object->string data))
 

tests/goldfish/liii/lang-test.scm

@@ -751,6 +751,12 @@
 (check ($ '(2 3 4) :reduce *) => 24)  
 (check ($ '(5) :reduce (lambda (x y) (+ x y 10))) => 5)
 
+(check ($ '() :reduce-option +) => (none))
+
+(check ($ '(1 2 3) :reduce-option +) => (option 6))  
+(check ($ '(2 3 4) :reduce-option *) => (option 24))  
+(check ($ '(5) :reduce-option (lambda (x y) (+ x y 10))) => (option 5))
+
 (check (object->string ($ '(1 2 3))) => "(1 2 3)")
 
 (let1 l (rich-list (list 1 2 3))