🍏 Fix imports

README.md

@@ -68,46 +68,47 @@ message Greeting {
 You can run the following:
 
 ```sh
-protoc -I . --python_betterproto_out=. example.proto
+mkdir lib
+protoc -I . --python_betterproto_out=lib example.proto
 ```
 
-This will generate `hello.py` which looks like:
+This will generate `lib/hello/__init__.py` which looks like:
 
-```py
+```python
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
-# sources: hello.proto
+# sources: example.proto
 # plugin: python-betterproto
 from dataclasses import dataclass
 
 import betterproto
 
 
 @dataclass
-class Hello(betterproto.Message):
+class Greeting(betterproto.Message):
     """Greeting represents a message you can tell a user."""
 
     message: str = betterproto.string_field(1)
 ```
 
 Now you can use it!
 
-```py
->>> from hello import Hello
->>> test = Hello()
+```python
+>>> from lib.hello import Greeting
+>>> test = Greeting()
 >>> test
-Hello(message='')
+Greeting(message='')
 
 >>> test.message = "Hey!"
 >>> test
-Hello(message="Hey!")
+Greeting(message="Hey!")
 
 >>> serialized = bytes(test)
 >>> serialized
 b'\n\x04Hey!'
 
->>> another = Hello().parse(serialized)
+>>> another = Greeting().parse(serialized)
 >>> another
-Hello(message="Hey!")
+Greeting(message="Hey!")
 
 >>> another.to_dict()
 {"message": "Hey!"}
@@ -315,7 +316,7 @@ To benefit from the collection of standard development tasks ensure you have mak
 
 This project enforces [black](https://github.com/psf/black) python code formatting.
 
-Before commiting changes run:
+Before committing changes run:
 
 ```sh
 make format
@@ -336,7 +337,7 @@ Adding a standard test case is easy.
 
 - Create a new directory `betterproto/tests/inputs/<name>`
   - add `<name>.proto`  with a message called `Test`
-  - add `<name>.json` with some test data
+  - add `<name>.json` with some test data (optional)
 
 It will be picked up automatically when you run the tests.
 

betterproto/__init__.py

@@ -7,27 +7,22 @@
 from abc import ABC
 from base64 import b64decode, b64encode
 from datetime import datetime, timedelta, timezone
-import stringcase
 from typing import (
     Any,
-    AsyncGenerator,
     Callable,
-    Collection,
     Dict,
     Generator,
-    Iterator,
     List,
-    Mapping,
     Optional,
     Set,
-    SupportsBytes,
     Tuple,
     Type,
     Union,
     get_type_hints,
 )
-from ._types import ST, T
-from .casing import safe_snake_case
+
+from ._types import T
+from .casing import camel_case, safe_snake_case, safe_snake_case, snake_case
 from .grpc.grpclib_client import ServiceStub
 
 if not (sys.version_info.major == 3 and sys.version_info.minor >= 7):
@@ -124,8 +119,8 @@ def datetime_default_gen():
 class Casing(enum.Enum):
     """Casing constants for serialization."""
 
-    CAMEL = stringcase.camelcase
-    SNAKE = stringcase.snakecase
+    CAMEL = camel_case
+    SNAKE = snake_case
 
 
 class _PLACEHOLDER:

betterproto/casing.py

@@ -1,9 +1,21 @@
-import stringcase
+import re
+
+# Word delimiters and symbols that will not be preserved when re-casing.
+# language=PythonRegExp
+SYMBOLS = "[^a-zA-Z0-9]*"
+
+# Optionally capitalized word.
+# language=PythonRegExp
+WORD = "[A-Z]*[a-z]*[0-9]*"
+
+# Uppercase word, not followed by lowercase letters.
+# language=PythonRegExp
+WORD_UPPER = "[A-Z]+(?![a-z])[0-9]*"
 
 
 def safe_snake_case(value: str) -> str:
     """Snake case a value taking into account Python keywords."""
-    value = stringcase.snakecase(value)
+    value = snake_case(value)
     if value in [
         "and",
         "as",
@@ -39,3 +51,70 @@ def safe_snake_case(value: str) -> str:
         # https://www.python.org/dev/peps/pep-0008/#descriptive-naming-styles
         value += "_"
     return value
+
+
+def snake_case(value: str, strict: bool = True):
+    """
+    Join words with an underscore into lowercase and remove symbols.
+    @param value: value to convert
+    @param strict: force single underscores
+    """
+
+    def substitute_word(symbols, word, is_start):
+        if not word:
+            return ""
+        if strict:
+            delimiter_count = 0 if is_start else 1  # Single underscore if strict.
+        elif is_start:
+            delimiter_count = len(symbols)
+        elif word.isupper() or word.islower():
+            delimiter_count = max(
+                1, len(symbols)
+            )  # Preserve all delimiters if not strict.
+        else:
+            delimiter_count = len(symbols) + 1  # Extra underscore for leading capital.
+
+        return ("_" * delimiter_count) + word.lower()
+
+    snake = re.sub(
+        f"(^)?({SYMBOLS})({WORD_UPPER}|{WORD})",
+        lambda groups: substitute_word(groups[2], groups[3], groups[1] is not None),
+        value,
+    )
+    return snake
+
+
+def pascal_case(value: str, strict: bool = True):
+    """
+    Capitalize each word and remove symbols.
+    @param value: value to convert
+    @param strict: output only alphanumeric characters
+    """
+
+    def substitute_word(symbols, word):
+        if strict:
+            return word.capitalize()  # Remove all delimiters
+
+        if word.islower():
+            delimiter_length = len(symbols[:-1])  # Lose one delimiter
+        else:
+            delimiter_length = len(symbols)  # Preserve all delimiters
+
+        return ("_" * delimiter_length) + word.capitalize()
+
+    return re.sub(
+        f"({SYMBOLS})({WORD_UPPER}|{WORD})",
+        lambda groups: substitute_word(groups[1], groups[2]),
+        value,
+    )
+
+
+def camel_case(value: str, strict: bool = True):
+    """
+    Capitalize all words except first and remove symbols.
+    """
+    return lowercase_first(pascal_case(value, strict=strict))
+
+
+def lowercase_first(value: str):
+    return value[0:1].lower() + value[1:]