I am writing a macro to send e-mails, using a rest api available in our company.
(The macro will be deployed as a sasautos macro.) The attachments parameter should allow to pass a list of file paths, so this should be valid code;

%send_mail(subject=Voorbeeld e-mail
    , [email protected]
    , message_html =Dear collegue<br/><br/>Here are the promised files.<br/><br/>Regards<br/>Dirk Horsten
    , attachments = "/our/data/répertoire français/file&today_yymmdd..xlsx" 
        "/our/data/some_folder/file with blanks.xlsx" 
    );

Within the macro %send_mail(), I would like to put the attachments parameter in a string attachment_list Perl Regular Expressions in SAS.

data _null_;
    ...
    length fileRef $8 xpath $256 ;
    attachment_list = "&attachments";
    _rxAttachment = prxParse('/".+?"/');
    _rxStart = 1;
    _rxStop = length(attachment_list);
    call prxNext(_rxAttachment, _rxStart, _rxStop, attachment_list, _rxPos, _rxLen);
    if not _rxPos then putlog 'WARNING: unable to parse your attachments';
    else do;
        attach_nr = 0;
        do while (_rxPos);
            attach_nr = attach_nr + 1;
            xpath = substr(attachment_list, _rxPos, _rxLen);
            fileRef = cats('_ML_',attach_nr);
            call execute (catx(' '
                , 'filename'
                , fileRef
                , xpath
                , ';'));
            length attachRef_N attachName_N attachType_N $32;
            attachRef_N = cats('attachRef_', attach_nr);                        
            call symputx(attachRef_N, fileRef, 'local');
            attachName_N = cats('attachName_', attach_nr);
            call symputx(attachName_N, scan(xpath, -1, '/'), 'local');
        end;
        call symputx('attach_count', attach_nr, 'local');
    end;
    ...
run;

(I hope I did not make errors while simplifying the code for you.)

However, the quotes within the parameter mess up with the quotes in attachment_list = "&attachments"; Does anyone see a work around, so that my users should not worry about this?

The following are not acceptable solutions:

• Ask my users to double their quotes, as in , attachments = ""/our/data/répertoire français/file1.xlsx"" ""/our/data/some_folder/file with blanks.xlsx"". (They would not understand and I would get one of them on the phone weekly.)
• Ask them to use ' instead of ", because then they cannot use macro variables within their call to my macro