Language > Miscellaneous Topics > Reserved Words

# Reserved Words

Variables, user-written procedures, and user-written functions should not have the same names as IDL functions or procedures. Re-using names of IDL routines can lead to syntax errors or to “hiding” variables. In addition, certain words representing IDL language constructs are strictly forbidden—using any of these reserved words as a variable, procedure, or function name will cause an immediate syntax error. The following table lists all of the reserved words in IDL.

AND | BEGIN | BREAK
CASE | COMMON | COMPILE_OPT
CONTINUE | DO | ELSE
END | ENDCASE | ENDELSE
ENDFOR | ENDFOREACH | ENDIF
ENDREP | ENDSWITCH | ENDWHILE
EQ | FOR | FOREACH
FORWARD_FUNCTION | FUNCTION | GE
GOTO | GT | IF
INHERITS | LE | LT
MOD | NE | NOT
OF | ON_IOERROR | OR
PRO | REPEAT | SWITCH
THEN | UNTIL | WHILE
XOR |  |