正则表达式不是解决这个问题的好方法。它们不能很好地处理多行搜索,并且它们可以表达的模式受到限制,例如,不可能用正则表达式指定任意嵌套。
解决此问题的正确方法是使用旨在处理 C 代码中的条件编译指令的工具。这将是编译器的 C 预处理器,或专用工具,例如unifdef
:
$ unifdef -UDEBUG file.c | grep printf
printf(some_parameters); // This should match
printf(some_parameters); // This should also match
从手册:
UNIFDEF(1) BSD General Commands Manual UNIFDEF(1)
NAME
unifdef, unifdefall — remove preprocessor conditionals from code
SYNOPSIS
unifdef [-ceklst] [-Ipath -Dsym[=val] -Usym -iDsym[=val] -iUsym] ... [file]
unifdefall [-Ipath] ... file
DESCRIPTION
The unifdef utility selectively processes conditional cpp(1) directives.
It removes from a file both the directives and any additional text that
they specify should be removed, while otherwise leaving the file alone.
The unifdef utility acts on #if, #ifdef, #ifndef, #elif, #else, and #endif
lines, and it understands only the commonly-used subset of the expression
syntax for #if and #elif lines. It handles integer values of symbols
defined on the command line, the defined() operator applied to symbols
defined or undefined on the command line, the operators !, <, >, <=, >=,
==, !=, &&, ||, and parenthesized expressions. Anything that it does not
understand is passed through unharmed. It only processes #ifdef and
#ifndef directives if the symbol is specified on the command line, other‐
wise they are also passed through unchanged. By default, it ignores #if
and #elif lines with constant expressions, or they may be processed by
specifying the -k flag on the command line.