Custom sampler

Author: jayvdb

requirements-dev.txt

@@ -7,3 +7,4 @@ tox==3.14.1
 twine==3.1.1
 volatile==2.1.0
 wheel==0.33.6
+sre-tools==0.0.1

sre_yield/__init__.py

@@ -325,6 +325,12 @@ def __repr__(self):
         )
 
 
+class SamplingRepetitiveSequence(SlicedSequence):
+    def __init__(self, content, lowest=1, highest=1):
+        real = RepetitiveSequence(content, lowest, highest)
+        super().__init__(real, slicer=slice(0, 2))
+
+
 class SaveCaptureGroup(WrappedSequence):
     def __init__(self, parsed, key):
         self.key = key
@@ -353,6 +359,8 @@ def get_item(self, i, d=None):
 class RegexMembershipSequence(WrappedSequence):
     """Creates a sequence from the regex, knows how to test membership."""
 
+    _RepetitiveSequence = RepetitiveSequence
+
     def empty_list(self, *_):
         return []
 
@@ -372,7 +380,7 @@ def max_repeat_values(self, min_count, max_count, items):
         """Sequential expansion of the count to be combinatorics."""
         max_count = min(max_count, self.max_count)
         max_count = max(max_count, min_count)
-        return RepetitiveSequence(self.sub_values(items), min_count, max_count)
+        return self._RepetitiveSequence(self.sub_values(items), min_count, max_count)
 
     def in_values(self, items):
         # Special case which distinguishes branch from charset operator

sre_yield/tests/test_sre_yield.py

@@ -17,6 +17,7 @@
 
 import io
 import re
+import sre_constants
 import sre_parse
 import sys
 import unittest
@@ -208,6 +209,49 @@ def testSlicingMatches(self):
         self.assertEqual(["a-a", "b-b"], [x.group(0) for x in parsed[:2]])
         self.assertEqual(["a", "b"], [x.group(1) for x in parsed[:2]])
 
+    def testCustomRepeater(self):
+        sample_codes = ["au", "us", "eu"]
+
+        class DomainExpander(sre_yield.SlicedSequence):
+            # Expand any \w\w pattern to be a country domain code
+            def __init__(self, content, lowest=1, highest=1):
+                if content.__len__() == len(
+                    sre_yield.CATEGORIES[sre_constants.CATEGORY_WORD]
+                ):
+                    if (
+                        "".join(iter(content))
+                        == sre_yield.CATEGORIES[sre_constants.CATEGORY_WORD]
+                    ):
+                        if lowest == 2 and highest == 2:
+                            super().__init__(sample_codes)
+                            return
+
+                real = sre_yield.RepetitiveSequence(content, lowest, highest)
+                super().__init__(real)
+
+        class CustomStrings(sre_yield.RegexMembershipSequence):
+            _RepetitiveSequence = DomainExpander
+
+            def __init__(
+                self,
+                pattern,
+                flags=0,
+                charset=sre_yield.CHARSET,
+                max_count=None,
+                relaxed=False,
+                simplify=False,
+            ):
+                if simplify:
+                    from sre_tools.simplify import simplify_regex
+
+                    pattern = simplify_regex(pattern)
+                super().__init__(pattern, flags, charset, max_count, relaxed)
+
+        self.assertEqual(list(CustomStrings(r"\w{2}")), sample_codes)
+        self.assertEqual(
+            list(CustomStrings(r"\w\w", simplify=True)), sample_codes
+        )
+
     def testSlicingMatchesMultichar(self):
         parsed = sre_yield.AllMatches("z([ab]{2})")
         self.assertEqual(4, len(parsed))