

ALGOL60 Manual Update


                    Algol (E) Compiler   [Nov. 1978]

The Algol (E) Compiler is not designed to allow  variables  to  be  used
before  declaration.   This  restriction is implied, rather than clearly
stated in the language manual and this will be  clarified  in  the  next
issue.   All  identifiers  (other  than  labels  which  do  not  require
declaration) must be  declared  before  use  apart  from  the  following
specific exceptions:

  1) Procedures may be called before the body is given to permit cross
     recursion.

  2) Switches may refer to switch elements in an undeclared switch list
     - this allows two switches to reference each other.

        e.g. %SWITCH SW:=L1,L2,L3,S[J];
             %SWITCH S:= SW[I],L5,L6;


   Any  programmer who insists on putting his declarations at the end of
blocks  should  use  PL/1,  the  only  language  which  encourages  such
behaviour.