To determine if a macro expects specific arguments (its signature) in SAS, you can use a custom macro that retrieves the macro's source code and parses its parameter list. Try this:
Step-by-Step Explanation
Check Macro Existence: Use %sysmacexist to verify the macro exists.
Retrieve Macro Source: Use %copy to access the macro's source code.
Parse Parameters: Extract the parameter list from the %macro statement, handling multi-line definitions and comments.
Compare Signatures: Clean and compare the extracted parameters against the expected signature.
%macro MacSignatureCheck(macroname, expected_params);
%local fileref params expected_clean rc start end;
%let fileref = %sysfunc(tempfilename(fn));
/* Clean expected parameters: uppercase and remove spaces */
%let expected_clean = %sysfunc(compress(%upcase(&expected_params), %str( )));
/* Attempt to copy macro source */
%let rc = %sysfunc(filename(fileref, &fileref));
%let copystat = %sysfunc(copy(¯oname, &fileref, SOURCE));
%if ©stat ne 0 %then %do;
%put WARNING: Could not copy macro ¯oname source.;
filename &fileref clear;
%return(0);
%end;
/* Read and parse macro source to extract parameters */
data _null_;
infile &fileref lrecl=32767 truncover;
length combined $32767 temp $32767 line $32767;
retain combined '';
input line $char32767.;
combined = cat(strip(combined), strip(line));
/* Continue reading until closing ')' if needed */
if index(combined, '(') and not index(combined, ')') then do until (eof);
do until (index(temp, ')') or eof);
input line $char32767.;
if _error_ then eof = 1;
temp = cat(strip(temp), strip(line));
end;
combined = cat(strip(combined), strip(temp));
end;
/* Remove comments */
combined = prxchange('s/\/\*.*?\*\///', -1, combined);
/* Extract parameters from %MACRO statement */
start = index(upcase(combined), '(');
end = index(upcase(combined), ')');
if start and end then do;
params = substr(combined, start+1, end - start -1);
params = compress(upcase(params), ' '); /* Remove spaces */
call symputx('params', params);
end;
run;
/* Determine result and clean up */
filename &fileref clear;
%if "%superq(params)" = "&expected_clean" %then 1;
%else 0;
%mend MacSignatureCheck;
/* Example usage in data step */
data _null_;
set control_validated;
call execute('%nrstr(%include) ' || quote(trim(program)) || ';');
parameter = 'wedge_postmacro';
if symexist(parameter) then do;
macro = symget(parameter);
if not missing(macro) then do;
exists = resolve('%sysmacexist(' || trim(macro) || ')');
if exists then do;
/* Check if signature matches */
length result $1;
result = resolve('%MacSignatureCheck(' || trim(macro) || ', %nrstr(x, y, z, foo=, bar=))');
if result = '1' then do;
call execute('%nrstr(%' || trim(macro) ||
'(x=' || cats(controlX) ||
', y=' || cats(controlY) ||
', z=' || cats(controlZ) ||
', foo=' || cats(controlFoo) ||
', bar=' || cats(controlBar) || '));');
end;
end;
end;
end;
run;
Explanation
Macro %MacSignatureCheck :
Copies Source: Uses %copy to retrieve the macro's source code.
Reads and Parses: Extracts the parameter list from the %macro statement, handling multi-line definitions and removing comments.
Compares Parameters: Cleans (uppercase, no spaces) and compares against the expected parameters.
Data Step Integration:
Checks Existence: Uses %sysmacexist to verify the macro exists.
Calls %MacSignatureCheck : Uses resolve to dynamically check the macro's signature.
Generates Call: If the signature matches, uses call execute to generate the macro call safely.
This approach dynamically verifies a macro's signature before invocation, preventing potential errors from mismatched parameters.
Hope this helps somehow.
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