simpler error messages

Author: NejcS

plain_file.py

@@ -136,7 +136,7 @@ def check_if_functional_requirements_are_specified(plain_source, non_functional_
 
     found_functional_requirements = plain_spec.FUNCTIONAL_REQUIREMENTS in plain_source
     if found_functional_requirements and len(non_functional_requirements) == 0:
-        raise PlainSyntaxError("Plain syntax error: Syntax error: functionality with no implementation reqs specified.")
+        raise PlainSyntaxError("Plain syntax error: functionality with no implementation reqs specified.")
 
     return found_functional_requirements
 
@@ -348,7 +348,7 @@ def process_imports(
         for specification_heading in plain_file_parse_result.plain_source:
             if specification_heading not in plain_spec.ALLOWED_IMPORT_SPECIFICATION_HEADINGS:
                 raise PlainSyntaxError(
-                    f"Plain syntax error: Syntax error: Invalid specification heading (`{specification_heading}`). Allowed headings: {', '.join(plain_spec.ALLOWED_IMPORT_SPECIFICATION_HEADINGS)}"
+                    f"Plain syntax error: Invalid specification heading (`{specification_heading}`). Allowed headings: {', '.join(plain_spec.ALLOWED_IMPORT_SPECIFICATION_HEADINGS)}"
                 )
 
             if plain_source[specification_heading] is None:
@@ -377,7 +377,7 @@ def read_plain_source_metadata(plain_source_text):
     try:
         plain_source_obj = frontmatter.loads(plain_source_text)
     except Exception as e:
-        raise PlainSyntaxError(f"Plain syntax error: Syntax error: Invalid frontmatter: {e}")
+        raise PlainSyntaxError(f"Plain syntax error: Invalid frontmatter: {e}")
 
     for directive in [EXPORTED_CONCEPTS_DIRECTIVE, REQUIRED_CONCEPTS_DIRECTIVE]:
         if directive in plain_source_obj.metadata:
@@ -393,7 +393,7 @@ def read_plain_source_metadata(plain_source_text):
                     prepared_metadata.append(f"- {item}")
                 else:
                     raise PlainSyntaxError(
-                        f"Plain syntax error: Syntax error: Invalid {directive} metadata. Expected a dictionary or a string."
+                        f"Plain syntax error: Invalid {directive} metadata. Expected a dictionary or a string."
                     )
 
             plain_source_obj.metadata[directive] = prepared_metadata
@@ -576,13 +576,13 @@ def process_required_modules(
             for concept in plain_file_parse_result.plain_source_obj.metadata[EXPORTED_CONCEPTS_DIRECTIVE]:
                 if concept in concept_utils.DEFAULT_CONCEPTS:
                     raise PlainSyntaxError(
-                        f"Plain syntax error: Syntax error: Default concept cannot be exported: {concept}. Only user-defined concepts can be exported."
+                        f"Plain syntax error: Default concept cannot be exported: {concept}. Only user-defined concepts can be exported."
                     )
 
                 if isinstance(concept, str):
                     exported_concepts.extend(concept_utils.extract_concepts_from_definition(concept)[0])
                 else:
-                    raise PlainSyntaxError(f"Plain syntax error: Syntax error: Invalid exported concept: {concept}.")
+                    raise PlainSyntaxError(f"Plain syntax error: Invalid exported concept: {concept}.")
 
             with PlainRenderer() as renderer:
                 for exported_concept in exported_concepts:
@@ -645,11 +645,13 @@ def plain_file_parser(  # noqa: C901
         missing_required_concepts_msg = "Missing required concepts: "
         missing_required_concepts_msg += ", ".join(plain_file_parse_result.required_concepts)
         raise PlainSyntaxError(
-            f"Plain syntax error: Syntax error: Not all required concepts were defined. {missing_required_concepts_msg}."
+            f"Plain syntax error: Not all required concepts were defined. {missing_required_concepts_msg}."
         )
 
     if not check_if_functional_requirements_are_specified(plain_file_parse_result.plain_source, []):
-        raise PlainSyntaxError("Plain syntax error: Syntax error: No functionality specified.")
+        raise PlainSyntaxError(
+            f"Plain syntax error: Module '{module_name}' was required but does not contain functional requirements."
+        )
 
     exported_definitions = process_required_modules(
         plain_file_parse_result.required_modules,