refactored config into its own file

Author: ivanharvard

check50/__init__.py

@@ -41,15 +41,15 @@ def _setup_translation():
     run,
     log, _log,
     hidden,
-    Failure, Mismatch, Missing, Config,
-    configure
+    Failure, Mismatch, Missing,
 )
 
 
 from . import regex
 from .runner import check
+from .config import config
 from pexpect import EOF
 
 __all__ = ["import_checks", "data", "exists", "hash", "include", "regex",
            "run", "log", "Failure", "Mismatch", "Missing", "check", "EOF",
-           "Config", "configure"]
+           "config"]

check50/_api.py

@@ -11,6 +11,7 @@
 from pexpect.exceptions import EOF, TIMEOUT
 
 from . import internal, regex
+from .config import config
 
 _log = []
 internal.register.before_every(_log.clear)
@@ -469,38 +470,6 @@ def _safe_truncate(x, y):
 
         self.payload.update({"expected": expected, "actual": actual})
 
-
-class Config:
-    """
-    Configuration for check50 behavior.
-
-    This class stores user-defined configuration options (currently only
-    truncation length) that influence check50’s output formatting.
-    """
-    def __init__(self):
-        self.truncate_len = 10
-        self.dynamic_truncate = True
-
-config = Config()
-
-def configure(truncate_len=None):
-    """
-    Configure check50 behavior.
-
-    By default, check50 truncates strings around their first point of difference.
-    However, if the user specifies a custom `truncate_len` via `check50.configure`,
-    then string outputs will be sliced from the beginning instead.
-
-    Example usage::
-        import check50
-        check50.configure(truncate_len=15)
-    """
-    if truncate_len:
-        if not isinstance(truncate_len, int) or truncate_len < 1:
-            raise ValueError("truncation length must be a positive integer")
-        config.truncate_len = truncate_len
-        config.dynamic_truncate = False
-
 def hidden(failure_rationale):
     """
     Decorator that marks a check as a 'hidden' check. This will suppress the log
@@ -530,7 +499,7 @@ def wrapper(*args, **kwargs):
         return wrapper
     return decorator
 
-def _truncate(s, other, max_len=10):
+def _truncate(s, other):
     def normalize(obj):
         if isinstance(obj, list):
             return "\n".join(map(str, obj))

check50/config.py

@@ -0,0 +1,77 @@
+class Config:
+    """
+    Configuration for `check50` behavior.
+
+    This class stores user-defined configuration options that influence
+    check50's output formatting.
+
+    For developers of `check50`, you can extend the `Config` class by adding new
+    variables to the `__init__`, which will automatically generate new "setter"
+    functions to modify the default values. Additionally, if the new
+    configuration needs to be validated before the user can modify it, add your
+    validation into the `_validators` dictionary.
+    """
+    def __init__(self):
+        self.truncate_len = 10
+        self.dynamic_truncate = True
+
+        # Create boolean validators for your variables here (if needed):
+        # A help message is not required.
+        self._validators = {
+            "truncate_len": (lambda val: isinstance(val, int) and val >= 1,
+                             "truncate_len must be a positive integer"),
+        }
+
+        # Dynamically generates setter functions based on variable names and
+        # the type of the default values
+        self._generate_setters()
+
+    def _generate_setters(self):
+        def create_method(name, func):
+            setattr(self.__class__, name, func)
+
+        def make_toggle(attr):
+            """Factory for making functions like `toggle_<attr_name>()`"""
+            def toggler(self):
+                setattr(self, attr, not getattr(self, attr))
+            return toggler
+
+        def make_setter(attr):
+            """Factory for making functions like `set_<attr_name>(arg)`"""
+            def setter(self, value):
+                # Get the entry in the dict of validators.
+                # Check to see if the value passes the validator, and if it
+                # didn't, display the help message, if any.
+                validator_entry = self._validators.get(attr)
+
+                if validator_entry:
+                    if isinstance(validator_entry, tuple):
+                        validator, help = validator_entry
+                    else:
+                        validator, help = validator_entry, None
+
+                    if not validator(value):
+                        error_msg = f"invalid value for {attr}: {value}"
+                        if help:
+                            error_msg += f", {help}"
+                        raise ValueError(error_msg)
+
+                setattr(self, attr, value)
+            return setter
+
+        for attribute_name in dir(self):
+            if attribute_name.startswith('_'):
+                continue # skip "private" attributes (denoted with a prefix `_`)
+            value = getattr(self, attribute_name)
+            if callable(value):
+                continue # skip functions/methods
+
+            # For variables with the default boolean type, make a setter that
+            # starts with `toggle_`. Otherwise, have it start with `set_`.
+            if isinstance(value, bool):
+                create_method(f"toggle_{attribute_name}", make_toggle(attribute_name))
+            else:
+                create_method(f"set_{attribute_name}", make_setter(attribute_name))
+
+
+config = Config()