Parser fails when .uvl file contains blank lines or comments

[jmhorcas]

I think the grammar should be updated by replacing NEWLINE by NEWLINE+ where correspond (different places at all such as between features, between constraints, and at the end of the file).

Moreover, the comments are also delicated and crashes (for example comments in the constraints section).

[MiriamGaus]

Can you give an example when these problems occur? I can parse this without any error:

// This is a comment
features 


    // This is a comment
    A 

        or 

            B {Price 2, Fun 12} 
            C {Price 7, Fun 6} 
            D {Price 5, Fun 8} 


constraints



    // This is a comment
    B.Fun + C.Fun - B.Price == 16
    B.Fun + (C.Fun - B.Price) == 16 // This is a comment

    
    B.Fun + C.Fun * B.Price == 20 // This is a comment

    // This is a comment

[jmhorcas]

I think the error about comments only occurs in the Python version of the grammar.

[jmhorcas]

Here I provide 5 examples to reproduce 5 errors with the Python parser of UVL. Maybe this is because it is not clear how and where comments, and blanklines are allowed. But I also think these kind of errors should be easy to handle them in the grammar (Python version), lexer, or parser. For instance the first error can be easily fixed in the handleNewline method of the Python customer lexer to omit the appropriate token.

1. Errors with blank lines
Example:

namespace Pizza

features
	Pizza {abstract}
		mandatory
			Topping
				or
					Salami
					Ham
					Mozzarella
			Size
				alternative
					Normal
					Big
			Dough

				alternative
					Neapolitan
					Sicilian
		optional
			CheesyCrust

constraints
	CheesyCrust => Big

Error: The UVL has the following warning that prevents reading it :Line 17:4 - mismatched input '\t\t\t\t' expecting {<EOF>, 'constraints'}
Cause: The blank line in line 16 between feature Dough and the alternative keyword.

===========================================================================
2. Errors with inline comments in blank lines
Example:

namespace Pizza

features
	Pizza {abstract}
		mandatory
			Topping
				or
					Salami
					Ham
					Mozzarella
			// Size is a xor-group feature
			Size
				alternative
					Normal
					Big
			Dough
				alternative
					Neapolitan
					Sicilian
		optional
			CheesyCrust

constraints
	CheesyCrust => Big

Error: Exception: The UVL has the following error that prevents reading it :Line 12:3 - mismatched input 'Size' expecting {<EOF>, 'constraints'}
Cause: The inline comment in line 11 before the feature Size.

===========================================================================
3. Errors with block comments inside the features block
Example:

namespace Pizza

features
	/*
 	This is the feature hierarchy
	*/
	Pizza {abstract}
		mandatory
			Topping
				or
					Salami
					Ham
					Mozzarella
			Size
				alternative
					Normal
					Big
			Dough
				alternative
					Neapolitan
					Sicilian
		optional
			CheesyCrust

constraints
	CheesyCrust => Big

Error: The UVL has the following warning that prevents reading it :Line 8:1 - extraneous input '\t' expecting {'String', 'Integer', 'Real', 'Boolean', ID_NOT_STRICT, ID_STRICT}
Cause: The block comment before the root feature

===========================================================================
4. Errors with tabs inside blank lines
Example:

namespace Pizza

features
	Pizza {abstract}
		mandatory
			Topping
				or
					Salami
					Ham
					Mozzarella
			Size
				alternative
					Normal
					Big
			Dough
				alternative
					Neapolitan
					Sicilian
		optional
			CheesyCrust
	
constraints
	CheesyCrust => Big

Error: Exception: The UVL has the following error that prevents reading it :Line 23:0 - extraneous input '\n' expecting '<DEDENT>'
Cause: The blank line 22 just after the constraints contain an invisible tab (indentation).

===========================================================================
5. Errors with more than one blanklines at the end of files
Example:

namespace Pizza

features
	Pizza {abstract}
		mandatory
			Topping
				or
					Salami
					Ham
					Mozzarella
			Size
				alternative
					Normal
					Big
			Dough
				alternative
					Neapolitan
					Sicilian
		optional
			CheesyCrust
constraints
	CheesyCrust => Big

Error: Exception: The UVL has the following error that prevents reading it :Line 25:0 - extraneous input '\n' expecting <EOF>
Cause: The end of file contains two blanklines.

[SundermannC]

Thanks a lot for the detailed report, @jmhorcas! That is very helpful. I will test if any of these UVL models also cause issues in the Java parser. @jagalindo How do we want to continue with the issues in the Python part?