Route function extraction through a Language type.

Each language implements functions. An unknown language returns nothing.

src/crapper/languages/__init__.py

@@ -1,22 +1,27 @@
 """Per-language function extraction."""
 
-from crapper.languages import clojure, golang, java, python, rust, typescript
+from crapper.languages.clojure import Clojure
+from crapper.languages.golang import Go
+from crapper.languages.java import Java
+from crapper.languages.language import Unknown
+from crapper.languages.python import Python
+from crapper.languages.rust import Rust
+from crapper.languages.typescript import TypeScript
 from crapper.model import Function
 
+_LANGUAGES = {
+    "clojure": Clojure(),
+    "java": Java(),
+    "go": Go(),
+    "typescript": TypeScript(),
+    "python": Python(),
+    "rust": Rust(),
+}
+_UNKNOWN = Unknown()
+
 
 def functions_in_file(
     language: str, source: str, path: str, project_root: str
 ) -> list[Function]:
-    if language == "clojure":
+    chosen = _LANGUAGES.get(language, _UNKNOWN)
-        return clojure.functions_in_source(source, path, project_root)
+    return chosen.functions(source, path, project_root)
-    if language == "java":
-        return java.functions_in_source(source, path)
-    if language == "go":
-        return golang.functions_in_source(source, path, project_root)
-    if language == "typescript":
-        return typescript.functions_in_source(source, path, project_root)
-    if language == "python":
-        return python.functions_in_source(source, path, project_root)
-    if language == "rust":
-        return rust.functions_in_source(source, path, project_root)
-    return []

src/crapper/languages/clojure.py

@@ -7,6 +7,7 @@ variants, `and`, `or`, `loop`, `catch`, and each clause of `cond`, `condp`,
 
 import re
 
+from crapper.languages.language import Language
 from crapper.model import Function
 
 _DECISION = re.compile(
@@ -285,3 +286,8 @@ def functions_in_source(
         )
         for item in extract_functions(source)
     ]
+
+
+class Clojure(Language):
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        return functions_in_source(source, path, project_root)

src/crapper/languages/golang.py

@@ -19,6 +19,7 @@ from crapper.languages.treesitter import (
     parse,
     start_line,
 )
+from crapper.languages.language import Language
 from crapper.model import Function
 
 _DECISIONS = {
@@ -149,3 +150,8 @@ def functions_in_source(
             )
         )
     return found
+
+
+class Go(Language):
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        return functions_in_source(source, path, project_root)

src/crapper/languages/java.py

@@ -17,6 +17,7 @@ from crapper.languages.treesitter import (
     parse,
     start_line,
 )
+from crapper.languages.language import Language
 from crapper.model import Function
 
 _PACKAGE = re.compile(r"(?m)^\s*package\s+([a-zA-Z_][\w.]*)\s*;")
@@ -114,3 +115,8 @@ def functions_in_source(source: str, path: str) -> list[Function]:
 
     visit(tree.root_node)
     return found
+
+
+class Java(Language):
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        return functions_in_source(source, path)

src/crapper/languages/language.py

@@ -0,0 +1,16 @@
+"""The operation every language implements."""
+
+from abc import ABC, abstractmethod
+
+from crapper.model import Function
+
+
+class Language(ABC):
+    @abstractmethod
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        """Functions and methods defined in one source file."""
+
+
+class Unknown(Language):
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        return []

src/crapper/languages/python.py

@@ -16,6 +16,7 @@ from crapper.languages.treesitter import (
     parse,
     start_line,
 )
+from crapper.languages.language import Language
 from crapper.model import Function
 
 _DECISIONS = {
@@ -131,3 +132,8 @@ def functions_in_source(
             )
         )
     return found
+
+
+class Python(Language):
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        return functions_in_source(source, path, project_root)

src/crapper/languages/rust.py

@@ -20,6 +20,7 @@ from crapper.languages.treesitter import (
     parse,
     start_line,
 )
+from crapper.languages.language import Language
 from crapper.model import Function
 
 _DECISIONS = {
@@ -186,3 +187,8 @@ def functions_in_source(
         if recorded is not None:
             found.append(recorded)
     return found
+
+
+class Rust(Language):
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        return functions_in_source(source, path, project_root)

src/crapper/languages/typescript.py

@@ -17,6 +17,7 @@ from crapper.languages.treesitter import (
     parse,
     start_line,
 )
+from crapper.languages.language import Language
 from crapper.model import Function
 
 _DECISIONS = {
@@ -178,3 +179,8 @@ def functions_in_source(
         elif node.type == "lexical_declaration":
             _append_arrows(found, data, node, module, path)
     return found
+
+
+class TypeScript(Language):
+    def functions(self, source: str, path: str, project_root: str) -> list[Function]:
+        return functions_in_source(source, path, project_root)

tests/test_languages.py

@@ -0,0 +1,23 @@
+import pytest
+
+from crapper.languages import functions_in_file
+
+_SOURCES = [
+    ("clojure", "(defn choose [x] x)\n", "src/demo/core.clj", "choose"),
+    ("java", "class Board { void place() { if (true) return; } }\n", "Board.java", "place"),
+    ("go", "package demo\nfunc Place() int { return 1 }\n", "board.go", "Place"),
+    ("typescript", "export function view() { return 1 }\n", "src/ui.ts", "view"),
+    ("python", "def run():\n    return 1\n", "src/app.py", "run"),
+    ("rust", "pub fn open() {}\n", "src/lib.rs", "open"),
+]
+
+
+@pytest.mark.parametrize(("language", "source", "path", "name"), _SOURCES)
+def test_each_language_answers_the_same_message(language, source, path, name):
+    found = functions_in_file(language, source, path, "/proj")
+    assert found[0].name == name
+    assert found[0].language == language
+
+
+def test_unknown_language_has_no_functions():
+    assert functions_in_file("ruby", "def x\nend\n", "a.rb", "/proj") == []