unifdef - Delete code guarded by processor directives

Author: Anders Lindgren
Version: 0.0.2
URL: https://github.com/Lindydancer/unifdef

unifdef is a package that can delete code guarded by C-style preprocessor directives.

Examples

Take this relatively simple code:

#ifdef USELONGLONG
long long x;
#else
long x;
#endif

M-x unifdef-current-buffer RET USELONGLONG RET will transform this into:

long long x;

A (somewhat) more complex piece of code:

#if ALPHA
  Alpha();
#elif BETA
  Beta();
#elif GAMMA
  Gamma();
#else
  Delta();
#endif

M-x unifdef-current-buffer RET BETA RET will transform this into:

#if ALPHA
  Alpha();
#else
  Beta();
#endif

What is converted

This package can convert code that test if a symbol is defined or if a symbol is true. For example:

#ifdef SYMBOL

#if defined SYMBOL

#if defined(SYMBOL)

#if SYMBOL

Or if the symbol is undefined or false:

#ifndef SYMBOL

#if !defined SYMBOL

#if !defined(SYMBOL)

#if !SYMBOL

And likewise for elif.

What is not converted

This package does not handle complex expressions involving symbols. For example:

#if ALPHA && BETA

#if ALPHA == 1234

#if (ALPHA ^ BETA) == 0x1234

#if defined(ALPHA) && defined(BETA)

Commands

• unifdef-current-buffer -- Convert all occurrences in the current buffer.
• unifdef-convert-block -- Convert the next preprocessor block. (Note, in some cases, this command might need to be applied repeatedly.)

When prefixed with C-u the command is inverted, i.e. it assumes that the supplied symbol is undefined or false. In the example above, the line long x; would be retained.

Warning

The command provided by this package can perform massive changes to your source files. Make sure that they are backed up, e.g. by using a version control system. As for all tools that automatically transform source code, it is advisable to manually inspect the end result.

---

Converted from unifdef.el by el2markdown.