Seperate view code and clarify the proof

undone/Makefile

@@ -3,7 +3,7 @@ SITEDIR = $(shell pkg-config guile-2.0 --variable=sitedir \
 	--define-variable=prefix=$(DESTDIR))
 COMPDIR = $(DESTDIR)/lib/guile/2.0/site-ccache
 
-objects = main.scm main.go
+objects = main.scm main.go view.scm view.go
 install-objects = $(addprefix install-,$(objects))
 uninstall-objects = $(addprefix uninstall-,$(objects))
 

undone/main.scm

@@ -2,6 +2,7 @@
   #:use-module (ice-9 format)
   #:use-module (ice-9 rdelim)
   #:use-module (oop goops)
+  #:use-module (undone view)
   #:export (main))
 
 (define-syntax get-field
@@ -161,31 +162,6 @@
                             (string->number (car args)))))
                 todo-list)))
 
-(define-class <view> ())
-
-(define-generic print-view)
-(define-generic sort-view)
-(define-generic filter-view)
-
-(define-method (sort-view (v <view>) l)
-  l)
-
-(define-method (filter-view (v <view>))
-  (lambda (elm)
-    (and (assq 'id elm) (assq 'content elm))))
-
-(define-method (print-view (v <view>))
-  (for-each
-   (lambda (item)
-     (let ((id (let ((field (assq 'id item)))
-                 (and field (cdr field))))
-           (content
-            (let ((field (assq 'content item)))
-              (and field (cdr field)))))
-       (if #t (format #t "~2d ~a~%" id content))))
-   (filter (filter-view v)
-           (sort-view v todo-list))))
-
 (define-class <todo-view> (<view>))
 
 (define-method (sort-view (v <todo-view>) l)
@@ -193,8 +169,13 @@
 
 (define-method (filter-view (v <todo-view>))
   (lambda (elm)
-    (let ((id (assq 'id elm)))
+    (let ((state (assq 'state elm)))
-    (and id (> (cdr id) 4)))))
+      (and state (not (string= (cdr state) "done"))))))
+
+(define-method (print-item (v <todo-view>) item)
+  (format #t "~a ~a~%"
+          (cdr (assq 'state item))
+          (cdr (assq 'content item))))
 
 (define-view default
   "Default todo-list view, show only the title."
@@ -241,4 +222,4 @@
                     (car view) (procedure-documentation (cdr view))))
           view-list))))
 
-  (print-view (make <todo-view>)))
+  (print-view (make <todo-view> #:todo-list todo-list)))

undone/view.scm

@@ -0,0 +1,33 @@
+(define-module (undone view)
+  #:use-module (oop goops)
+  #:export (<view> sort-view filter-view print-item get-list-for
+                   print-view))
+
+(define-generic sort-view)
+(define-generic filter-view)
+(define-generic print-item)
+(define-generic get-list-for)
+(define-generic print-view)
+
+(define-class <view> ()
+  (todo-list #:init-value '() #:init-keyword #:todo-list))
+
+(define-method (sort-view (v <view>) l) l)
+
+(define-method (print-item (v <view>) item)
+  (format #t "~2d ~a~%"
+          (cdr (assq 'id item))
+          (cdr (assq 'content item))))
+
+(define-method (filter-view (v <view>))
+  (lambda (elm)
+    (and (assq 'id elm) (assq 'content elm))))
+
+(define-method (get-list-for (v <view>))
+  (filter (filter-view v)
+          (sort-view v (slot-ref v 'todo-list))))
+
+(define-method (print-view (v <view>))
+  (for-each
+   (lambda (item) (print-item v item))
+   (get-list-for v)))