What am I doing to generate the SAS error: "Required operator not found in expression"?

What am I doing to generate the SAS error: "Required operator not found in expression"?

以下代码生成上述错误。我正在寻找一个解释。请帮忙。

%GLOBAL var;
%LET var = 1;

%MACRO test;
%IF &var. in (1,2) %THEN %DO;
    %PUT &var.;
%END;
%MEND;

%test;

ERROR: Required operator not found in expression: &var. in (1,2)

%IF 中对“In”的使用需要更改为以下代码。或者使用 %index 函数

%GLOBAL var;
 %LET var = 1;

 %MACRO test;
 %IF **&var.=1 or &var.=2** %THEN %DO;
     %PUT &var.;
 %END;

 %if %index
 %MEND test;

 %test;