When you define macro variables, you can include macro
functions in the expressions to manipulate the value of the variable
before the value is stored. For example, you can use functions that
scan other values, evaluate arithmetic and logical expressions, and
remove the significance of special characters such as unmatched quotation
marks.
To scan for words in
macro variable values, use the %SCAN function:
%let address=123 maple avenue;
%let frstword=%scan(&address,1);
The first %LET statement
assigns the string
123 maple avenue to macro
variable ADDRESS. The second %LET statement uses the %SCAN function
to search the source (first argument) and retrieve the first word
(second argument). Because the macro processor executes the %SCAN
function before it stores the value, the value of FRSTWORD is the
string
123.