topic Re: To semicolon or not to semicolon in SAS Programming

To semicolon or not to semicolon

DJWanna — Fri, 31 Jul 2009 14:16:01 GMT

We are having a bit of a debate here ... I am an old time SAS programmer who was told that it is better to semicolon after a macro call ... %macroname; There is another thought that one must never semicolon ... %macroname.

My thinking is that if there were unbalanced semicolons at least this one would make sure that the macro would run. However, there is a note in a course note publication that states the opposite. I know there are times when if a macro call was in the middle of other code it may not be appropriate. I am just wondering about the call itself as stand alone code.

Your thoughts?
Thanks!

Re: To semicolon or not to semicolon

Flip — Fri, 31 Jul 2009 14:30:26 GMT

After 25 years, I almost always put in the semicolon. I have known programmers who put a semicolon in empty lines as spacers. In most cases it will not hurt, and helps locate things in debugging.

I also insist on hard returns and RUN; statements which I often see left out of code.

Re: To semicolon or not to semicolon

Peter_C — Fri, 31 Jul 2009 15:04:32 GMT

another old $0.02
sometimes the statement needs to be completed with a semicolon after the macro is called.
The macros which generate steps, usually, finish by generating a semicolon on a "run;" Those which generate only statements usually deliver statements completed by a semicolon. These macro invocations should not need a trailing semicolon.
I use a lot of "sub-statement" macros. They are really useful when a string or value needs to be retrieved. These "sub-statement macros" generate no semicolon so that they can be used, for example, in a calculation. It is normally important that these sub-statement macros are not immediately followed by a semicolon.
For example:
%put the message at %now() needs action ;

The semicolon ends the statement, not the macro invocation.

PeterC

Re: To semicolon or not to semicolon

Flip — Fri, 31 Jul 2009 15:11:21 GMT

Agreed. One really needs to know the context in which a macro is to be used. In the case of a sub-statement type of macr. I make it clear in the documentation if no semi-colon is to be used.

Re: To semicolon or not to semicolon

ChrisNZ — Thu, 03 Jan 2019 20:13:03 GMT

The semicolon after the macro call will never be used, will it? (actually if it is part of the logic of the macro-generated code, it should be inside the macro itself).

The only reasonable case when a semicolon will be used after the macro call is when it closes a non-macro statement, as in
title %write_title(big, red, bold);
but then the semicolon is there to close the title statement, not as part of the macro call.

>I have known programmers who put a semicolon in empty lines as spacers.

Unless you are one of these and like extra and unused semicolons, a semicolon after a macro call makes no sense.

My 2 cents, to each their own and all that. Having an extra ; is not a big sin (though it sometimes hides bad understanding of how macros work).

Edited. The deficient color parser is sadly a reason to use an ending semicolon, as it gets confused without this explicit statement delimiter.

Re: To semicolon or not to semicolon

DanielSantos — Mon, 03 Aug 2009 07:40:57 GMT

Yep, agree with Chris. No need for any semicolon after the macro call.

But in my case, sometimes the habit of terminating any line of code with a semicolon takes over this understanding. Indeed, not a big sin.

Now, a situation that I found to be particularly confusing to understand for some sas coders is the need of a semicolon after the %if %then macro statement, say something like this:

%macro x(TAB,KEEP,VARS);

data _null_;
set &TAB %if &KEEP %then (keep = &VARS);;
run;

/* OR */

data _null_;
set &TAB %if &KEEP %then (keep = &VARS); end = _EOF;
run;

%mend x;

Cheers from Portugal.

Daniel Santos at www.cgd.pt.