RE-flex not generating FSM transitions when outfile has cxx extension.

[SouravKB]

RE-flex tool is not generating FSM transitions when outfile has cxx transitions. I'm not sure whether this is intended behavior. But in documentation, I didn't find this being mentioned.

Steps to reproduce:

1. Write a valid lex program.
2. Add line %o outfile=lex.cxx.
3. RE-flex tool will now leave TABLES part empty in the generated output.

[genivia-inc]

Indeed, only .hpp, .cpp and .cc are recognized filename extensions at this time. This is decided in lib/pattern.cpp function gencode_dfa.

Should we add .cxx as well as upper case versions like .CPP, .CC and .CXX?

[genivia-inc]

lib/pattern.cpp:2812 gencode_dfa change to:

    if ((len > 2 && filename.compare(len - 2, 2, ".h"  ) == 0)
     || (len > 3 && filename.compare(len - 3, 3, ".hh" ) == 0)
     || (len > 4 && filename.compare(len - 4, 4, ".hpp") == 0)
     || (len > 4 && filename.compare(len - 4, 4, ".hxx") == 0)
     || (len > 3 && filename.compare(len - 3, 3, ".cc" ) == 0)
     || (len > 4 && filename.compare(len - 4, 4, ".cpp") == 0)
     || (len > 4 && filename.compare(len - 4, 4, ".cxx") == 0))

[SouravKB]

I don't want to use .cxx in particular. However, if this is the case, it should probably mentioned in the documentation explicitly. I had to spend time in-order to figure out why reflex suddenly stopped generating tables without giving any warnings or errors.

Note that, GCC recognizes .cc, .C, .cp, .cpp, .CPP, .cxx, .c++ file extensions as C++ source file & .h, .hh, .H, .hp, .hpp, .HPP, .hxx, .h++, .tcc file extensions as C++ header file.

[SouravKB]

My personal suggestion is that, if user is allowed to specify the filename, then let user use whatever extension he wants. Why constrain that. If you want, you may generate a warning instead.

[genivia-inc]

Nope. There are cases where we want to generate a graphviz file with extension .gv, i.e. extensions affect the type of output produced.