[Cpptool-develop] Refactoring in presence of preprocessor #ifdef...

[Baptiste L. <gai...@fr...>]

    I've just made a breakthrough concerning refactoring code that contains
alternative code blocks selected by the preprocessor (#if #else #endif
stuffs).

    The solution is fairly simple: the transformation that represents a
refactoring applied on a source with multiple code alternatives is the union
of the transformations of the refactoring applied on each code alternative.

    Take for example the following slice of code (from boost.filesystem):
---
      inline bool dot_or_dot_dot( const char * name )
      {
# if !BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x0564) )
        return std::strcmp( name, "." ) == 0
            || std::strcmp( name, ".." ) == 0;
# else
        return name[0]=='.'
          && (name[1]=='\0' || (name[1]=='.' && name[2]=='\0'));
# endif
      }
---

    Say you want to rename the parameter 'name'.

    You first apply the refactoring on the code using the first alternative.
You obtains a first set of transformations.

    Then, you apply the refactoring on the code using the second
alternative. You obtains a second set of transformations.

    Adding the two sets of transformation give you the transformation to two
for this refactoring.

    There is still a lot to be worked out (how to you select code
alternatives in a coherent way...), but I believe there core idea is there.

    Baptiste.