当宏以与宏后面的字符串相同的字符结尾时，使m4看到宏 [英] make m4 see macro when macro ends with same character as string following macro

问题描述

我正在使用M4扩展某些文件的系统上工作，但是在某些情况下扩展遇到问题.定义/宏命名的约定(如果可能，我宁愿不要更改)为__<name>__(即，双下划线和下划线.)因此，此扩展正确:

I'm working on a system that uses M4 to expand some files out, but I'm getting a problem with the expansion in certain cases. The convention for definition / macro naming (which I'd rather not change if possible) is __<name>__ (i.e. double leading and trailing underscores.) So this expands correctly:

define(`__ROOT__', `/home/mydir')
...
__ROOT__/bin

给予

/home/mydir/bin

但是

define(`__PREFIX__', `App_Mnemonic')
...
__PREFIX___some_service

应给出:

App_Mnemonic_some_service

但是给出

__PREFIX___some_service

(即它错过了扩展)

我认为宏的尾部下划线与基础文本的有效下划线之间缺少空格会使m4感到困惑.有什么我可以做的吗?我是否可以使用无声括号来分隔宏，例如环境变量?

I presume the lack of space between the trailing underscore of the macro and the valid underscore of the underlying text is confusing m4. Is there anything I can do about this? Can I delimit the macro with silent braces, for example, like enviromnment variables?

推荐答案

看似简单，我在底层文本中要做的就是更改此内容:

Deceptively simple really, all I had to do in the underlying text was change this:

__PREFIX___some_service

为此:

__PREFIX__()_some_service

也许看起来有些笨拙，但是毕竟它是一个宏，不需要更改宏定义.因此，可以保持原样:

It looks a bit clunky perhaps, but it is a macro after all and there's no need to change the macro definition. So this can stay as it is:

define(`__PREFIX__', `App_Mnemonic')

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