implement AnswerRegistry and AnswerWidget

* new class exercise.Textarea that implements AnswerWidget
* CodeDemo implements AnswerWidget
* CodeDemo: merge member functions handle_checks_result and _output_results
* add _utils.py with Printer static class for nicer printing using termcolor
* replace prints with Printer.print_* functions
* adapt save css style to more readable
* parameters in ParameterPanel are now settable

pyproject.toml

@@ -31,7 +31,8 @@ dependencies = [
   "ipywidgets>=8.0.0",
   "numpy",
   "widget_code_input",
-  "matplotlib"
+  "matplotlib",
+  "termcolor"
 ]
 dynamic = ["version"]
 

src/scwidgets/_utils.py

@@ -0,0 +1,16 @@
+from termcolor import colored
+
+
+class Printer:
+    # move to output
+    @staticmethod
+    def print_error_message(message: str):
+        print(colored(message, "red", attrs=["bold"]))
+
+    @staticmethod
+    def print_success_message(message: str):
+        print(colored(message, "green", attrs=["bold"]))
+
+    @staticmethod
+    def print_info_message(message: str):
+        print(colored(message, "blue", attrs=["bold"]))

src/scwidgets/answer/__init__.py

@@ -0,0 +1,3 @@
+from ._widget_answer_registry import AnswerRegistry, AnswerWidget
+
+__all__ = ["AnswerWidget", "AnswerRegistry"]