Faust passes invalid --class-name and --super-class-name identifiers to generated code

[Pri-yan-shu]

Faust doesn't correctly modify --class-name and --super-class-name to valid c++ identifiers and generates uncompilable c++ code. Its bigger issue with faust2.. scripts using filename as classname, for instance faust2lv2, so filenames that are valid (for instance starting with a digit or containing hyphen) result in error during the compilation of the generated c++ code.

[Oshangsurtani]

I have already developed a prototype of this solution. Could you please review this approach, @sletz ?

Approach

The solution is to sanitize the provided identifier strings to ensure they conform to C++ identifier rules. The key steps are:

1. Validation and Sanitization Function
   Create a helper function (e.g., sanitizeIdentifier) that:

   • Checks the first character: If it is a digit, prepend an underscore.
   • Filters through the rest of the string: Convert any illegal character (anything other than alphanumerics or underscore) into an underscore.
   • Optionally: Warn the user if the provided identifier is changed, so they are aware of the transformation.

2. Integrate the Sanitization Function
   Modify the part of the Faust code where --class-name and --super-class-name are processed. Instead of using the raw input, pass the input through the sanitization function before using it in code generation.