Multilevel Referencing Of Macro In SAS - &&&&&&&& MACRO VARIABLE

Hi,

We can use any number of ampersands (&) in an indirect macro variable reference.

SAS resolves the entire reference from left to right. If a pair (double) of ampersands (&&) is encountered, the pair (double) is resolved to single ampersand, then the next part of the reference is processed.

Suppose we have following macro variables:

%let a=UMA;

%let UMA=SHANKER;

%let SHANKER=SAINI;

And we are going to check the output of the following PUT statements with multiple macro variables.

%put &a;

 %put &&a;

%put &&&a;

%put &&&&a;

%put &&&&&a;

%put &&&&&&a;

%put &&&&&&&a;

And output would be something like this:

%put &a;   * UMA *;

%put &&a;  * UMA *;

%put &&&a; * SHANKER * ;

 Explanation: && resolves to single & (put in reserve)  resolve &a to UMA, now with reserve & sas reads &UMA , result is SHANKER.

%put &&&&a; * UMA . pairing && and && comes to && resolves to & *;

Explanation: && resolves to single & (put in reserve) again && resolve to single & (put in reserve), now we have only a, no execution. in reserve we have && which is &a. again result is UMA.

%put &&&&&a;

Explanation: && resolves to single & (put in reserve) again && resolve to single & (put in reserve), now we have &a, resolve to UMA. In reserve we have two ampersand, which is one (&) and now it is &UMA, resolve to SHANKER.

%put &&&&&&a;

Explanation: && resloves to single & (put in reserve) again && resolve to single & (put in reserve) , && resolve to single & (put in reserve), now we have only a , no execution. In reserve we have &&& so again result is SHANKER.

%put &&&&&&&a;

Explanation: Would resolve to SAINI, because we would have three ampersand (in reserve) and &a resolve to UMA. &&&UMA resolve to &SHANKER and it would resolve to SAINI.