summary: refactoring to use the formatting vocab + tests

basis/summary/summary-tests.factor

@@ -0,0 +1,5 @@
+USING: summary tools.test ;
+IN: summary.tests
+
+{ "string with 5 elements" } [ "hello" summary ] unit-test
+{ "hash-set with 3 members" } [ HS{ 1 2 3 } summary ] unit-test

basis/summary/summary.factor

@@ -1,38 +1,26 @@
 ! Copyright (C) 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors assocs classes continuations kernel make math
-math.parser sequences sets ;
+USING: accessors assocs classes continuations formatting kernel math
+sequences sets strings ;
 IN: summary
 
 GENERIC: summary ( object -- string )
 
 : object-summary ( object -- string ) class-of name>> ; inline
 
+: container-summary ( obj size word -- str )
+    [ object-summary ] 2dip "%s with %d %s" sprintf ;
+
 M: object summary object-summary ;
 
 M: sequence summary
-    [
-        dup class-of name>> %
-        " with " %
-        length #
-        " elements" %
-    ] "" make ;
+    dup length "elements" container-summary ;
 
 M: assoc summary
-    [
-        dup class-of name>> %
-        " with " %
-        assoc-size #
-        " entries" %
-    ] "" make ;
+    dup assoc-size "entries" container-summary ;
 
 M: unordered-set summary
-    [
-        dup class-of name>> %
-        " with " %
-        cardinality #
-        " members" %
-    ] "" make ;
+    dup cardinality "members" container-summary ;
 
 ! Override sequence => integer instance
 M: f summary object-summary ;