Added possibility to create own transformations

Author: marverix

README.md

@@ -30,26 +30,30 @@ import casey
 
 subject = "every 1 WORD is very IMPORTANT"
 
-subject = casey.camel(subject)
-print(subject)
+print(casey.camel(subject))
 # Prints: every1WORDIsVeryIMPORTANT
 
-subject = casey.kebab(subject)
-print(subject)
+print(casey.kebab(subject))
 # Prints: every-1-WORD-is-very-IMPORTANT
 
-subject = casey.pascal(subject)
-print(subject)
+print(casey.pascal(subject))
 # Prints: Every1WORDIsVeryIMPORTANT
 
-subject = casey.snake(subject)
-print(subject)
+print(casey.snake(subject))
 # Prints: every_1_WORD_is_very_IMPORTANT
 
-subject = casey.snake(subject, upper=True)
-print(subject)
+print(casey.snake(subject, upper=True))
 # Prints: EVERY_1_WORD_IS_VERY_IMPORTANT
 
+def my_transformation(idx: int, word: str) -> str:
+  if idx % 2 == 0:
+    return word.lower()
+  else:
+    return word.upper()
+  
+print(casey.transform(subject, my_transformation, "_"))
+# Prints: every_1_word_IS_very_IMPORTANT
+
 ```
 
 ### API
@@ -88,9 +92,15 @@ print(subject)
 
     Returns string with lower first letter (A-Z).
 
+* `transform(subject: str, transformation: Callable, glue=" ") -> str: ...`
+
+    Returns string transformed by the transformation function.
+    The transformation function accepts 2 parameters: current word index (int), and a word itself (str).
+    Glue is the string used to concat transformed words into one string.
+
 ## License
 
 This project is licensed under Apache-2.0 License - see the [LICENSE](LICENSE) file for details.
 
 
-[![FOSSA Status](https://app.fossa.com/api/projects/git%2Bgithub.com%2Fmarverix%2Fcasey.svg?type=large)](https://app.fossa.com/projects/git%2Bgithub.com%2Fmarverix%2Fcasey?ref=badge_large)
+[![FOSSA Status](https://app.fossa.com/api/projects/git%2Bgithub.com%2Fmarverix%2Fcasey.svg?type=large)](https://app.fossa.com/projects/git%2Bgithub.com%2Fmarverix%2Fcasey?ref=badge_large)

casey/__init__.py

@@ -1,4 +1,5 @@
 import re
+from typing import List, Callable, Union
 
 
 def clean(subject: str) -> str:
@@ -30,35 +31,60 @@ def clean(subject: str) -> str:
     return subject
 
 
+def clean_list(subject: str) -> List[str]:
+    return clean(subject).split(" ")
+
+
+def transform(subject: str, transformation: Union[Callable, None], glue=" ") -> str:
+    normalized = clean_list(subject)
+    words = []
+    for idx, word in enumerate(normalized):
+        if transformation:
+            w = transformation(idx, word)
+        else:
+            w = word
+        words.append(w)
+
+    return glue.join(words)
+
+
+def _camel_transformation(idx: int, word: str) -> str:
+    if idx == 0:
+        return word
+    else:
+        return upper_first(word)
+
+
 def camel(subject: str) -> str:
     """
     Returns string in camelCase
     """
-    normalized_subject = clean(subject)
-    return re.sub(r" [a-z0-9]", lambda m: m.group(0)[1].upper(), normalized_subject, flags=re.IGNORECASE)
+    return transform(subject, _camel_transformation, "")
+
+
+def _pascal_transformation(idx: int, word: str) -> str:
+    return upper_first(word)
 
 
 def pascal(subject: str) -> str:
     """
     Returns string in PascalCase
     """
-    return upper_first(camel(subject))
+    return transform(subject, _pascal_transformation, "")
 
 
 def kebab(subject: str) -> str:
     """
     Returns string in kebab-case
     """
-    normalized_subject = clean(subject)
-    return re.sub(r"\s", '-', normalized_subject)
+    return transform(subject, None, "-")
 
 
 def snake(subject: str, upper=False) -> str:
     """
     Returns string in snake_case
     """
-    normalized_subject = clean(subject)
-    s = re.sub(r"\s", '_', normalized_subject)
+    s = transform(subject, None, "_")
 
     if upper:
         s = s.upper()

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "casey"
-version = "1.0.3"
+version = "1.1.0"
 description = "A simple library to support various naming conventions and convert strings from one to another"
 authors = [
     "Marek Sierociński <mareksierocinski@gmail.com>"