Re: IF / ELSE / ENDIF macros for M4

[Mr. Clif]

    Hello again,
    
    what do you all think about including something like these with the
    other examples in the upcoming release?
    
    Another person wanting this a while back:
       
https://stackoverflow.com/questions/19059432/triple-conditional-check-with-ifdef-in-m4
    
        Any thoughts? :-)
        Clif

On 4/7/21 9:58 AM, Mr. Clif wrote:

Greetings,

I heard a long time ago that CPP was derived from M4, and read that a few folks including myself have looked for IF / ENDIF type macros to use on other projects. CPP is not ideal in that it wants to take extra steps like tokenizing the source.

Here is a post from someone else looking:

https://stackoverflow.com/questions/50549946/conditional-compilation-interpretation-using-m4/66978338#66978338

So not finding anything like this, I wrote some that seem to work pretty well. Here they are:

http://www.eugeneweb.com/wiki/Sites/M4Macros

I defined the names without the #'s eg. IF, ELSE, ENDIF, etc... Also M4 requires parentheses to hold the arguments where CPP does not (at least for most of these). I also added a selective invoke, to protect macros with side effects from invocation in an unselected block.

I was wondering if they pass muster, if the devs might consider including them or something similar in M4's list of examples. 

    Best,
    Clif