The ?PAIRS word

Bonjour to all,

In the archive of the group, I found the word "?PAIRS"
as in

: ENDCASE  4 ?PAIRS COMPILE DROP
                    BEGIN SP@[EMAIL PROTECTED]
 CSP @[EMAIL PROTECTED]
 = 0=
                      WHILE 2 [COMPILE ENDIF REPEAT
                    CSP ! ; IMMEDIATE

According the FAQ, the ?PAIRS word was  FIG-Forth's way of implementing a 
small amount of syntax checking.

Is "Number ?PAIRS" similar to ...  over <> if (error message) then ...;

Thanks for the help.