Add VTMLBuffer.split

Same semantics as str.split except the default sep is just `' '`.

shellish/rendering/vtml.py

@@ -529,6 +529,27 @@ def startswith(self, other):
     def endswith(self, other):
         return self.text().endswith(other)
 
+    def split(self, sep=' ', maxsplit=None):
+        if not sep:
+            raise ValueError("empty separator")
+        splits = []
+        pos = 0
+        text = self.text()
+        sep_len = len(sep)
+        while maxsplit is None or len(splits) < maxsplit:
+            try:
+                end = text.index(sep, pos)
+            except ValueError:
+                break
+            splits.append((pos, end))
+            pos = end + sep_len
+        splits.append((pos, None))
+        return [self[start:end] for start, end in splits]
+        if splits:
+            return [self[start:end] for start, end in splits]
+        else:
+            return [self.copy()]
+
 
 def vtmlrender(vtmarkup, plain=None, strict=False, vtmlparser=VTMLParser()):
     """ Look for vt100 markup and render vt opcodes into a VTMLBuffer. """

test/rendering.py

@@ -416,6 +416,37 @@ def test_in(self):
         self.assertNotIn('ABCD', abc)
         self.assertNotIn('abcd', abc)
 
+    def test_split_maxsplit(self):
+        ref = 'abc ABC xyz XYZ'
+        vs = R.vtmlrender(ref)
+        self.assertListEqual(vs.split(), ref.split(' '))
+        for i in range(6):
+            with self.subTest(i):
+                self.assertListEqual(vs.split(maxsplit=i), ref.split(' ', i))
+
+    def test_split_leading(self):
+        for ref in (' ', ' abc', '  ', '  abc'):
+            vs = R.vtmlrender(ref)
+            self.assertListEqual(vs.split(), ref.split(' '))
+
+    def test_split_trailing(self):
+        for ref in ('abc ', 'abc  ', ' abc ', '  abc  '):
+            vs = R.vtmlrender(ref)
+            self.assertListEqual(vs.split(), ref.split(' '))
+
+    def test_split_notfound(self):
+        ref = 'abc'
+        vs = R.vtmlrender(ref)
+        self.assertListEqual(vs.split('D'), ref.split('D'))
+        self.assertListEqual(vs.split('abcd'), ref.split('abcd'))
+        self.assertListEqual(vs.split('bcd'), ref.split('bcd'))
+
+    def test_split_multichar(self):
+        for ref in ('abcGAPABC', 'abcGAP', 'GAPabc', 'abGAPABGAP', 'aGAPbGAPc'):
+            vs = R.vtmlrender(ref)
+            self.assertListEqual(vs.split('GAP'), ref.split('GAP'))
+
+
 class HTMLConversion(unittest.TestCase):
 
     a_format = '<blue><u>%s</u></blue>'