Macro Quoting

The macro language is a character-based language. Even variables that appear to be numeric are generally treated as character variables (except during expression evaluation). Therefore, the macro processor enables you to generate all sorts of special characters as text. But because the macro language includes some of the same special characters, an ambiguity often arises. The macro processor must know whether to interpret a particular special character (for example, a semicolon or % sign) or a mnemonic (for example, GE or AND) as text or as a symbol in the macro language. Macro quoting functions resolve these ambiguities by masking the significance of special characters so that the macro processor does not misinterpret them.

The following special characters and mnemonics might require masking when they appear in text strings:

Macro quoting functions tell the macro processor to interpret special characters and mnemonics as text rather than as part of the macro language. If you did not use a macro quoting function to mask the special characters, the macro processor or the rest of SAS might give the character a meaning that you did not intend. Here are some examples of the types of ambiguities that can arise when text strings contain special characters and mnemonics:

Macro quoting functions enable you to clearly indicate to the macro processor how it is to interpret special characters and mnemonics.

Here is an example, using the simplest macro quoting function, %STR. Suppose you want to assign a PROC PRINT statement and a RUN statement to the macro variable PRINT. Here is the erroneous statement:

%let print=proc print; run;;  /* undesirable results */

This code is ambiguous. Are the semicolons that follow PRINT and RUN part of the value of the macro variable PRINT, or does one of them end the %LET statement? If you do not tell the macro processor what to do, it interprets the semicolon after PRINT as the end of the %LET statement. So the value of the PRINT macro variable would be the following:

proc print

The rest of the characters (RUN;;) would be simply the next part of the program.

To avoid the ambiguity and correctly assign the value of PRINT, you must mask the semicolons with the macro quoting function %STR, as follows:

%let print=%str(proc print; run;);

The following macro quoting functions are most commonly used:

For the paired macro quoting functions, the function beginning with NR affects the same category of special characters that are masked by the plain macro quoting function as well as ampersands and percent signs. In effect, the NR functions prevent macro and macro variable resolution. To help you remember which does which, try associating the NR in the macro quoting function names with the words “not resolved” — that is, macros and macro variables are not resolved when you use these functions.

The macro quoting functions with B in their names are useful for macro quoting unmatched quotation marks and parentheses. To help you remember the B, try associating B with “by itself”.

The %SUPERQ macro quoting function is unlike the other macro quoting functions in that it does not have a mate and works differently. See %SUPERQ Function for more information.

The macro quoting functions can also be divided into two types, depending on when they take effect:

The %SUPERQ function takes as its argument a macro variable name (or a macro expression that yields a macro variable name). The argument must not be a reference to the macro variable whose value you are masking. That is, do not include the & before the name.

Using an execution macro quoting function in the macro definition is the simplest and best way to have the macro processor accept resolved values that might contain special characters. However, if you discover that you need to pass parameter values such as or when a macro has not been defined with an execution macro quoting function, you can do so by masking the value in the macro invocation. The logic of the process is as follows:

For example, suppose a macro named ORDERX does not use the %BQUOTE function. You can pass the value or to the ORDERX macro with the following invocation:

%orderx(%str(or))

However, placing the macro quoting function in the macro definition makes the macro much easier for you to invoke.