difference between parameter macro and positional macro

[FriedEgg]

Only the one for which I posted the log information along with the macro, where I used parmbuf (single f as posted).  Also tried with 2 f's but still failed to compile.

[Peter_C]

with apologies to FriedEgg, Tom and Art

I have crossed some wires:smileyshocked: and provided serious miss-guidance

PARMBUFF needs both F

the macro definition with /parmbuff  DOES cause errors when a "positional" parameter follows keyword parameters in the definition.

My failing memory should have recalled that is in the invocation that /parmbuff (in the definition) might allow this rule of order to be broken.

As in this (more tested) version

107  %macro trouble() /parmbuff ;

108   %put  &syspBuff;

109  %mend ;

110

111  %trouble( ok=1, trouble=999, real_trouble );

( ok=1, trouble=999, real_trouble )

extending the macro a little is instructive

69   %macro trouble() /parmbuff ;

70    %put  &syspBuff; %* report the parameter list passed;

71    %put local environment _local_ (thats all !) ;

72   %mend ;

73

74   %trouble( ok=1, trouble=999, real_trouble );

( ok=1, trouble=999, real_trouble )

local environment _local_ (thats all !)

Although the macro appears to be invoked with parameters, none appear in the local environment.

If a parameter is defined in the macro definition, then it would appear in _local_ , but a miss-placed positional parameter will cause syntax ERROR

48   %macro trouble(ok=1, trouble=999) /parmbuff ;

49    %put  &syspBuff; %* report the parameter list passed;

50    %put local environment _local_ (thats all !) ;

51   %mend ;

52

53   %trouble( ok=1, trouble=999, real_trouble );

ERROR: All positional parameters must precede keyword parameters.

[Ksharp]

Art code should be

%trouble(  real_trouble ,ok=1, trouble=999);

Just as ERROR said in log.

ERROR: All positional parameters must precede keyword parameters.

BTW. I prefer to use call execute to instead of PARMBUFF, which only can supply one parameter.

Call execute can supply multiple parameters.

Ksharp

[Peter_C]

K

the idea here was to indicate that "the rule demanding positional parameters appear before keyword parameters" can appear to be broken with a macro defined with option parmbuff and no parameters. I would not recommend this - but it would be valid.

p

[Ksharp]

P

That would be broken by using parmbuff and &syspbuff. And I do not like &syspbuff any more.

I would use call execute to replace it now.

K

[Peter_C]

Ksharp

I can understand some of the reasons that make supplying parameters through call execute() more flexible

However, following up your comment

 I do not like &syspbuff any more

please would you expand this comment explaining features which cause your dislike?

peter

[Ksharp]

P

The mainly reason is that parmbuff only can handle a macro variable &syspbuff and also need type some more word , whereas  call execute support many macro variable and more brief more readable.

But That is not to say I hate to use &syspbuff, Everyone has oneself  taste. I just show myself.

K

[Peter_C]

thank you for explaining.

I have never had a context where I have needed parmbuff - and hope that continues. However, an interesting paper on parameter validation demonstrated the usefulness of parmbuff to deal with any collection of parameters.

Peter