+1 Charles
-----Original Message----- From: IBM Mainframe Assembler List [mailto:[email protected]] On Behalf Of Steve Smith Sent: Thursday, October 18, 2018 3:27 PM To: [email protected] Subject: Re: Macro Behavior I think in this case, ESPIE, it should check for extraneous operands. It evidently has a maximum of 3 positional operands, and it would certainly complain if MF(E(1)) was one of them. Re allowing a trailing comma: I wouldn't, and I think Jonathan's justification is off the mark. The check for too many positionals would include optional operands. Regular processing should normally treat an optional operand as unspecified if null anyway. So AIF (n'&SYSLIST GT max).error is sufficient. But if you insist, then AIF (n'&SYSLIST EQ max+1 AND '&SYSLIST(max+1)' EQ '').ok first. I've seen too many macros that are overzealous in checking things that don't matter, and things the assembler could catch just as well. This example is sort of a gray area (albeit dark gray) where the macro could process with what it got, but on the other hand could likely save some trouble by doing this extra check. A logical case could be made the macro processor could/should catch this itself. Undeclared positionals could be an automatic warning, like undeclared keywords are. But you'd need some way for macros to specify they will accept an arbitrary number of undeclared positional operands (because many do so). However, this is pretty much hypothetical, as I can't see it's worth the effort or incompatibility. sas On Thu, Oct 18, 2018 at 11:49 AM Jonathan Scott <[email protected]> wrote: > Ref: Your note of Thu, 18 Oct 2018 11:30:09 -0400 > > Steve Thompson writes: > > I have a question. If one passes too many positional arguments to > > a macro, should one not issue an MNOTE about this? > > > > Please try the following, and let me know what you think about this: > > > > ESPIE SET,MYRTN,(1,3,7),PARAM=(3),MF(E,(1)) > > It is obviously possible for a macro to check for too many positional > arguments. There are also many other ways in which macros could > typically perform intelligent extra validation on operands. > > However, on the other side, it is not normally the responsibility of the > macro writer to check for incorrect usage. Such checks could be > considered some "extra value" which the macro writer could add, if it is > considered worth while and does not add too much complexity. > > The usual principle in most product macros is only to check for errors > which mean that the macro is unable to continue, for example because a > required operand is missing or a keyword has an unsupported value. > > Personally, I include the "too many positional parameters" check in > most of the macros which I create. > > I check for ('&SYSLIST(n)' EQ '') where n is one more than the valid > number of positional parameters. I do this rather than checking > N'&SYSLIST so that it will tolerate a trailing comma, for example when > a macro has one positional parameter which is optional, so the user has > coded a dummy comma operand, which causes N'&SYSLIST to be set to 2 even > though only one positional operand is allowed. > > Of course, my check will not pick up a case where a spurious extra > positional parameter is preceded by two or more consecutive commas, > but it doesn't seem worth coding multiple checks to cover even more > obscure possibilities. > > Jonathan Scott, HLASM > IBM Hursley, UK > -- sas
