Extra list utilities, refactoring of some existing ones

pinyin/forms/preferencescontroller.py

@@ -70,7 +70,7 @@ def setUpViewPreview(self):
             keyedfieldnames.append((key, fieldname, wantcheckbox))
 
         # Build the fields in order of the label we assign to them: better than hash order!
-        checkwidgets = self.view.setupFields(sorted(keyedfieldnames, pinyin.utils.bySecond))
+        checkwidgets = self.view.setupFields(sorted(keyedfieldnames, pinyin.utils.using(pinyin.utils.snd)))
 
         # Set up all the checkboxes to map to the corresponding control flags
         for key, checkwidget in checkwidgets.items():

pinyin/tests/utils.py

@@ -43,12 +43,8 @@ def testSortedUsing(self):
         items = { "hello" : 1, "wide" : 2, "world" : 4 }
         self.assertEquals(sorted(["wide", "hello", "world"], using(items.get, inReverse())), ["world", "wide", "hello"])
         self.assertEquals(sorted(["wide", "hello", "world"], using(items.get)), ["hello", "wide", "world"])
-
-    def testSortedByFirst(self):
-        self.assertEquals(sorted([(5, "1"), (2, "4"), (3, "2"), (1, "5"), (4, "3")], byFirst), [(1, "5"), (2, "4"), (3, "2"), (4, "3"), (5, "1")])
-
-    def testSortedBySecond(self):
-        self.assertEquals(sorted([(5, "1"), (2, "4"), (3, "2"), (1, "5"), (4, "3")], bySecond), [(5, "1"), (3, "2"), (4, "3"), (2, "4"), (1, "5")])
+        self.assertEquals(sorted([(5, "1"), (2, "4"), (3, "2"), (1, "5"), (4, "3")], using(fst)), [(1, "5"), (2, "4"), (3, "2"), (4, "3"), (5, "1")])
+        self.assertEquals(sorted([(5, "1"), (2, "4"), (3, "2"), (1, "5"), (4, "3")], using(snd)), [(5, "1"), (3, "2"), (4, "3"), (2, "4"), (1, "5")])
 
     def testSortedInReverse(self):
         self.assertEquals(sorted([5, 2, 3, 1, 4], inReverse()), [5, 4, 3, 2, 1])

pinyin/utils.py

@@ -308,18 +308,6 @@ def parseHtmlColor(color):
 def using(proj, how=cmp):
     return lambda x, y: how(proj(x), proj(y))
 
-"""
-Sorting combinator: sort by first element
-"""
-def byFirst(x, y):
-    return cmp(x[0], y[0])
-
-"""
-Sorting combinator: sort by second element
-"""
-def bySecond(x, y):
-    return cmp(x[1], y[1])
-
 """
 Sorting combinator: reverse order:
 """
@@ -389,6 +377,10 @@ def inplacefilter(pred, list):
         if not pred(list[i - 1]):
             del list[i - 1]
 
+fst = lambda x: x[0]
+snd = lambda x: x[1]
+thd = lambda x: x[2]
+
 def first(f):
     def go(xy):
         x, y = xy
@@ -409,6 +401,12 @@ def cond(test, tb, fb):
     else:
         return fb()
 
+def concatmap(f, xs):
+    return concat(map(f, xs))
+
+def partition(p, xs):
+    return (filter(p, xs), filter(lambda x: not p(x), xs))
+
 def intersperse(what, things):
     first = True
     result = []