Date: Thu, 25 May 2006 15:25:20 +0000
Reply-To: toby dunn <tobydunn@HOTMAIL.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: toby dunn <tobydunn@HOTMAIL.COM>
Subject: Re: Understanding macro quoting (WAS: enterprise guide
peculiarities - %str())
In-Reply-To: <533D18F7F697A04DAA0BDB196E0871C1021D1724@ALPMLVEM05.e2k.ad.ge.com>
Content-Type: text/plain; format=flowed
Clinton ,
No your not the only one. However, aside from certain values like you
explained below macro uoting is way over used, ussually to compensate for
bad macro design. This is not to say that there arent valid reasons even
with good macro design to use macro quoting.
The best one in my opinion is by Ian :
http://www2.sas.com/proceedings/sugi28/011-28.pdf
I still think that there has to be a better way to explain macro quoting so
the whole thing doesnt confuse people. Guess I have a goal to shoot for.
Toby Dunn
From: "Rickards, Clinton (GE Consumer Finance)"
<clinton.rickards@GE.COM>
Reply-To: "Rickards, Clinton (GE Consumer Finance)"
<clinton.rickards@GE.COM>
To: SAS-L@LISTSERV.UGA.EDU
Subject: Understanding macro quoting (WAS: enterprise guide peculiarities
- %str())
Date: Thu, 25 May 2006 11:03:46 -0400
Ian,
Thanks for the note. I understand that %PUTting _all_ or _user_ yields
different results from %PUTting a single variable (just the way %put is
programmed).
Conceptually, I understand why quoting is needed:
1. special characters (i.e. non-alphabetic and non-digits) have meaning to
the macro sub-system. For example, & is generally used to denote the
begining of a macro variable reference (e.g. &fred), % is generally used to
denote the beginning of a macro call or reference (e.g. %my_macro), and a
comma (,) is used to separate arguments in macro functions.
2. sometimes I, as a programmer, have a different intent for those
characters. For example, I may want to have a macro variable contain the
constant string Chicken&Dumplings and force the macro processor to NOT
interpret the string &Dumplings as a macro variable reference.
Where I get totally confused, and I suspect I am not alone, is understanding
the multitude of quoting/unquoting macro functions that are available and
when they should/should not be used. Many of them seem to be too similar in
definition, at least for my level of understanding. Which is why my macros
are generally rudimentary but get the basic job done.
Are there any conference proceedings, etc, that I could look at that might
summarize the quoting "problem" and approaches to it?
Thanks,
Clint, the "confused" :)
-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU]On Behalf Of Ian
Whitlock
Sent: Wednesday, May 24, 2006 8:46 PM
To: SAS-L@LISTSERV.UGA.EDU
Subject: Re: enterprise guide peculiarities - %str()
Clinton,
The simple explanation is that
%put _all_ ;
doesn't have to write values the way
%put &var ;
does. They doesn't even have to be processed by the same code.
(Toby can never say anything in a few short sentences. He needs
paragraph to get started.)
On the other hand, there's more to it than that. (Under Widows,
the log shows little boxes instead of spaces.) Now try
%let x = / ;
%let y = %str(/) ;
proc sql ;
select name
, value format = $hex6. label = "Value in hex"
, ">>>" || put(value,$3.)||"<<<" label = "Printed Value in
corners"
from dictionary.macros
where name in ( "X" , "Y" )
;
quit ;
to see what the boxes or spaces represent. Then ask yourself what
might happen with
%put %eval("&x"="&y") ;
(The quotes are needed to hide the slash from %EVAL.) Yup, they are
equal. So why doesn't %EVAL have to tell the truth? Sometimes a lie
is more convenient than the truth. Consider how much work you would
have to do in order to find out that the symbol held by Y is the same
symbol as that held by X, if %EVAL wasn't willing to lie when it
comes to macro quoting.
On the other hand, quoting is a mechanism to say the symbol doesn't
have its expected meaning. Quoting isn't suppose to change the value.
It's suppose to hide the meaning not the value. So maybe it is SQL
that is lying and %EVAL is telling the truth.
Perhaps the question should be - why did you expect anything to be easy
when entered the world of quoting? Of course it isn't SI, SAS, or macro
that is the problem. It's quoting. Consider "BOSTON" and BOSTON. They
both have the same 6 letters. So how is it that only one has more than
a million people possible? If you still don't understand than read go
"Alice in Wonderland".
Maybe Toby's explanation wasn't so bad after all.
In case it isn't clear, none of this has anything to do with EG and its
pecularities. It just happens to be the scene of the crime.
Ian Whitlock
===============
Date: Wed, 24 May 2006 16:14:55 -0400
Reply-To: "Rickards, Clinton (GE Consumer Finance)"
<clinton.rickards@GE.COM>
Sender: "SAS(r) Discussion"
From: "Rickards, Clinton (GE Consumer Finance)"
<clinton.rickards@GE.COM>
Subject: Re: enterprise guide peculiarities - %str()
Comments: To: toby dunn <tobydunn@hotmail.com>
In-Reply-To: <BAY101-F21464D229780F3923D5410DE980@phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
Toby,
You're right, you wouldn't win any prizes with that explanation but it gets
the point across. Thanks...
-----Original Message-----
From: toby dunn [mailto:tobydunn@hotmail.com]
Sent: Wednesday, May 24, 2006 2:27 PM
To: Rickards, Clinton (GE Consumer Finance); SAS-L@LISTSERV.UGA.EDU
Subject: Re: enterprise guide peculiarities - %str()
Clinton ,
It gets complicated, well for me to explain in a few short sentences it
does. Think about it like this %str and %nrstr quote the value at compile
time. Which means that the value that is stored in the symbol tables is
masked. When quoting macro vars values the characters that are quoted get
transformed to a non printable characeter. All %put _User_ does is a dump
from this table to the log. Hence you see the slashes as blanks (they are
still nonprintable characters). The symbol tables just hold text values
and
rermember %put _User_ only asks for a dump of this to the log, not a dump
and a full resolution of the characters in it. The macro quoting and
unquoting and replacing of nonprintable characters for prinitng purposes
gets done outside of the symbol tables.
%put &Test3
The value from the resolution of test3 is still quoted, so for compile and
exectution time they are masked from the macro facility, but for printing
purposes SAS will replace the nonprintable chars with the correct ones.
This is probably a really bad explaination I will have to work on it some
more.
Toby Dunn
From: "Rickards, Clinton (GE Consumer Finance)"
<clinton.rickards@GE.COM>
Reply-To: "Rickards, Clinton (GE Consumer Finance)"
<clinton.rickards@GE.COM>
To: SAS-L
Subject: Re: enterprise guide peculiarities - %str()
Date: Wed, 24 May 2006 13:48:51 -0400
All,
Interesting... %PUT of the individual variable works but _all_ and _user_
does not in my environment (EG 3.0 talking to 9.1.3 on Solaris). Any
rational reason why not?
11 %let slashes = %str(//test/test2) ;
12 %let test3 = &slashes./test4 ;
13 %put %unquote(&slashes);
//test/test2
14 %put %unquote(&test3);
//test/test2/test4
15
16 %put #############;
#############
17 %put _ALL_;
GLOBAL _EGUSERID 222016322
GLOBAL _EGHOSTNAME srapdm01.usc.consfin.ge.com
GLOBAL _CLIENTUSERID 222016322
GLOBAL _EGUSERNAME 222016322
GLOBAL _EGSERVERNAME FraudMain
GLOBAL _EGMACHINE MYUSLWSHL203604
GLOBAL _SASHOSTNAME srapdm01.usc.consfin.ge.com
GLOBAL SLASHES test test2
GLOBAL _CLIENTAPP SAS Enterprise Guide
GLOBAL TEST3 test test2 /test4
GLOBAL _CLIENTUSERNAME 222016322
<snip>
18
19 %put #############;
#############
20 %put _user_;
GLOBAL _EGUSERID 222016322
GLOBAL _EGHOSTNAME srapdm01.usc.consfin.ge.com
GLOBAL _CLIENTUSERID 222016322
GLOBAL _EGUSERNAME 222016322
GLOBAL _EGSERVERNAME FraudMain
GLOBAL _EGMACHINE MYUSLWSHL203604
GLOBAL _SASHOSTNAME srapdm01.usc.consfin.ge.com
GLOBAL SLASHES test test2
GLOBAL _CLIENTAPP SAS Enterprise Guide
GLOBAL TEST3 test test2 /test4
GLOBAL _CLIENTUSERNAME 222016322
-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU]On Behalf Of toby
dunn
Sent: Wednesday, May 24, 2006 1:34 PM
To: SAS-L
Subject: Re: enterprise guide peculiarities - %str()
Jiann ,
When you reference a the macros in a %put statement they dont need to be
unquoted:
77 %let slashes = %str(//test/test2) ;
278 %let test3 = &slashes./test4 ;
279
280 %put &test3 ;
//test/test2/test4
281 %put &Slashes ;
//test/test2
Toby Dunn
From: Jiann-Shiun Huang <Jiann-Shiun.Huang@AMERUS.COM>
Reply-To: Jiann-Shiun Huang <Jiann-Shiun.Huang@AMERUS.COM>
To: SAS-L
Subject: Re: enterprise guide peculiarities - %str()
Date: Wed, 24 May 2006 12:02:56 -0500
Hans:
Use %unquote to restore the significance of symbols as the following
shows.
60 %let slashes = %str(//test/test2) ;
61 %let test3 = &slashes./test4 ;
62 %put %unquote(&slashes);
//test/test2
63 %put %unquote(&test3);
//test/test2/test4
J S Huang
1-515-557-3987
fax 1-515-557-2422
>>> Hans Schneider <hschneider@CMEDRESEARCH.COM> 05/24/06 11:44 AM >>>
Dear Listeners,
I stumbled over an irritating macro var resolution, using EG:
%let slashes = %str(//test/test2) ;
%let test3 = &slashes./test4 ;
%put _all_ ;
GLOBAL SLASHES test test2
GLOBAL TEST3 test test2 /test4
Slashes are not correctly reproduced (and brackets as well ?), when
the
string is enclosed in %str()...
...strange...
Any ideas ?
Cheers,
Hans
