diff --git a/projects/calf/BUILD b/projects/calf/BUILD
index bbb4124..c1e87be 100644
--- a/projects/calf/BUILD
+++ b/projects/calf/BUILD
@@ -2,8 +2,8 @@ package(default_visibility = ["//visibility:public"])
 
 py_library(
     name = "lib",
-    srcs = glob(["src/**/*.py"]),
-    imports = ["src"],
+    srcs = glob(["src/python/**/*.py"]),
+    imports = ["src/python"],
     deps = [
         py_requirement("pyrsistent"),
     ]
diff --git a/projects/calf/src/calf/__init__.py b/projects/calf/src/python/calf/__init__.py
similarity index 100%
rename from projects/calf/src/calf/__init__.py
rename to projects/calf/src/python/calf/__init__.py
diff --git a/projects/calf/src/calf/analyzer.py b/projects/calf/src/python/calf/analyzer.py
similarity index 100%
rename from projects/calf/src/calf/analyzer.py
rename to projects/calf/src/python/calf/analyzer.py
diff --git a/projects/calf/src/calf/cursedrepl.py b/projects/calf/src/python/calf/cursedrepl.py
similarity index 100%
rename from projects/calf/src/calf/cursedrepl.py
rename to projects/calf/src/python/calf/cursedrepl.py
diff --git a/projects/calf/src/calf/grammar.py b/projects/calf/src/python/calf/grammar.py
similarity index 100%
rename from projects/calf/src/calf/grammar.py
rename to projects/calf/src/python/calf/grammar.py
diff --git a/projects/calf/src/calf/io/reader.py b/projects/calf/src/python/calf/io/reader.py
similarity index 100%
rename from projects/calf/src/calf/io/reader.py
rename to projects/calf/src/python/calf/io/reader.py
diff --git a/projects/calf/src/calf/lexer.py b/projects/calf/src/python/calf/lexer.py
similarity index 100%
rename from projects/calf/src/calf/lexer.py
rename to projects/calf/src/python/calf/lexer.py
diff --git a/projects/calf/src/calf/packages.py b/projects/calf/src/python/calf/packages.py
similarity index 100%
rename from projects/calf/src/calf/packages.py
rename to projects/calf/src/python/calf/packages.py
diff --git a/projects/calf/src/calf/parser.py b/projects/calf/src/python/calf/parser.py
similarity index 100%
rename from projects/calf/src/calf/parser.py
rename to projects/calf/src/python/calf/parser.py
diff --git a/projects/calf/src/calf/reader.py b/projects/calf/src/python/calf/reader.py
similarity index 100%
rename from projects/calf/src/calf/reader.py
rename to projects/calf/src/python/calf/reader.py
diff --git a/projects/calf/src/calf/token.py b/projects/calf/src/python/calf/token.py
similarity index 100%
rename from projects/calf/src/calf/token.py
rename to projects/calf/src/python/calf/token.py
diff --git a/projects/calf/src/calf/types.py b/projects/calf/src/python/calf/types.py
similarity index 100%
rename from projects/calf/src/calf/types.py
rename to projects/calf/src/python/calf/types.py
diff --git a/projects/calf/src/calf/util.py b/projects/calf/src/python/calf/util.py
similarity index 100%
rename from projects/calf/src/calf/util.py
rename to projects/calf/src/python/calf/util.py
diff --git a/projects/calf/tests/BUILD b/projects/calf/tests/python/BUILD
similarity index 100%
rename from projects/calf/tests/BUILD
rename to projects/calf/tests/python/BUILD
diff --git a/projects/calf/tests/conftest.py b/projects/calf/tests/python/conftest.py
similarity index 100%
rename from projects/calf/tests/conftest.py
rename to projects/calf/tests/python/conftest.py
diff --git a/projects/calf/tests/test_grammar.py b/projects/calf/tests/python/test_grammar.py
similarity index 100%
rename from projects/calf/tests/test_grammar.py
rename to projects/calf/tests/python/test_grammar.py
diff --git a/projects/calf/tests/test_lexer.py b/projects/calf/tests/python/test_lexer.py
similarity index 100%
rename from projects/calf/tests/test_lexer.py
rename to projects/calf/tests/python/test_lexer.py
diff --git a/projects/calf/tests/test_parser.py b/projects/calf/tests/python/test_parser.py
similarity index 100%
rename from projects/calf/tests/test_parser.py
rename to projects/calf/tests/python/test_parser.py
diff --git a/projects/calf/tests/test_reader.py b/projects/calf/tests/python/test_reader.py
similarity index 100%
rename from projects/calf/tests/test_reader.py
rename to projects/calf/tests/python/test_reader.py
diff --git a/projects/calf/tests/test_types.py b/projects/calf/tests/python/test_types.py
similarity index 100%
rename from projects/calf/tests/test_types.py
rename to projects/calf/tests/python/test_types.py