Demunge namespaces specified via Python import machinery (#217)

Author: chrisrink10

src/basilisp/importer.py

@@ -9,6 +9,7 @@
 import basilisp.compiler as compiler
 import basilisp.lang.runtime as runtime
 import basilisp.reader as reader
+from basilisp.lang.util import demunge
 
 
 class BasilispImporter(MetaPathFinder, SourceLoader):
@@ -83,7 +84,8 @@ def exec_module(self, module):
         # a blank module. If we do not replace the module here with the module we are
         # generating, then we will not be able to use advanced compilation features such
         # as direct Python variable access to functions and other def'ed values.
-        ns: runtime.Namespace = runtime.set_current_ns(fullname).value
+        ns_name = demunge(fullname)
+        ns: runtime.Namespace = runtime.set_current_ns(ns_name).value
         ns.module = module
 
         forms = reader.read_file(filename, resolver=runtime.resolve_alias)
@@ -95,7 +97,7 @@ def exec_module(self, module):
         #
         # Later on, we can probably remove this and just use the 'ns macro to auto-refer
         # all 'basilisp.core values into the current namespace.
-        runtime.Namespace.add_default_import(fullname)
+        runtime.Namespace.add_default_import(ns_name)
 
 
 def hook_imports():

src/basilisp/lang/util.py

@@ -5,7 +5,7 @@
 import uuid
 from decimal import Decimal
 from fractions import Fraction
-from typing import Pattern
+from typing import Pattern, Match
 
 import dateutil.parser as dateparser
 
@@ -73,6 +73,24 @@ def munge(s: str, allow_builtins: bool = False) -> str:
     return new_s
 
 
+_DEMUNGE_PATTERN = re.compile(r"(__[A-Z]+__)")
+_DEMUNGE_REPLACEMENTS = {v: k for k, v in _MUNGE_REPLACEMENTS.items()}
+
+
+def demunge(s: str) -> str:
+    """Replace munged string components with their original
+    representation."""
+
+    def demunge_replacer(match: Match) -> str:
+        full_match = match.group(0)
+        replacement = _DEMUNGE_REPLACEMENTS.get(full_match, None)
+        if replacement:
+            return replacement
+        return full_match
+
+    return re.sub(_DEMUNGE_PATTERN, demunge_replacer, s).replace('_', '-')
+
+
 # Use an atomically incremented integer as a suffix for all
 # user-defined function and variable names compiled into Python
 # code so no conflicts occur

tests/basilisp/importer_test.py

@@ -1,7 +1,14 @@
+import importlib
+import os.path
 import sys
+import tempfile
 from unittest.mock import patch
 
+import _pytest.pytester as pytester
+
 import basilisp.importer as importer
+import basilisp.lang.runtime as runtime
+import basilisp.lang.symbol as sym
 
 
 def importer_counter():
@@ -22,3 +29,21 @@ def test_hook_imports():
         assert 1 == importer_counter()
         importer.hook_imports()
         assert 1 == importer_counter()
+
+
+def test_demunged_import(testdir: pytester.Testdir):
+    with tempfile.TemporaryDirectory() as tmpdir:
+        tmp_module = os.path.join(tmpdir, 'long__AMP__namespace_name__PLUS__with___LT__punctuation__GT__.lpy')
+        with open(tmp_module, mode='w') as module:
+            code = """
+            (ns long&namespace-name+with-<punctuation>)
+            """
+            module.write(code)
+
+        with patch('sys.path', new=[tmpdir]), \
+             patch('sys.meta_path', new=[importer.BasilispImporter()]):
+            importlib.import_module('long__AMP__namespace_name__PLUS__with___LT__punctuation__GT__')
+
+        assert runtime.Namespace.get(sym.symbol('long&namespace-name+with-<punctuation>')) is not None
+        assert runtime.Namespace.get(
+            sym.symbol('long__AMP__namespace_name__PLUS__with___LT__punctuation__GT__')) is None

tests/basilisp/langutil_test.py

@@ -0,0 +1,12 @@
+from basilisp.lang.util import demunge, _MUNGE_REPLACEMENTS
+
+
+def test_demunge():
+    for v, munged in _MUNGE_REPLACEMENTS.items():
+        assert demunge(munged) == v
+
+    assert "-->--" == demunge("____GT____")
+    assert "--init--" == demunge("__init__")
+    assert "random--V--" == demunge("random__V__")
+    assert "hi-how-are-you?" == demunge("hi_how_are_you__Q__")
+    assert "hi-how-are-you----" == demunge("hi_how_are_you____")

tests/basilisp/testrunner_test.py

@@ -1,11 +1,9 @@
 import _pytest.pytester as pytester
 
 
-# TODO: fix namespace after importer namespace issue resolved
-# (https://github.com/chrisrink10/basilisp/issues/206)
 def test_testrunner(testdir: pytester.Testdir):
     code = """
-    (ns test_fixture
+    (ns test-fixture
       (:require
        [basilisp.test :refer [deftest is]]))