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From: jlhaferman@l_eld09.icaen.uiowa.edu (Jeffrey Lawrence Haferman)
Newsgroups: comp.lang.fortran
Subject: Re: implicit none
Message-ID: <2087@ns-mx.uiowa.edu>
Date: 12 Aug 90 21:59:11 GMT
References: <246@cadlab.sublink.ORG>
Sender: news@ns-mx.uiowa.edu
Lines: 32

From article <246@cadlab.sublink.ORG>, by staff@cadlab.sublink.ORG (Alex Martelli):
> levine@crimee.ics.uci.edu (David Levine) writes:
>>John E. Davis writes:
>>>  VMS fortran has an extension to fortran that forces me to declare all
>>>this.  I was wondering if this will be a part of Fortran 90.  Also, what is
>>>the best way to simulate this effect?
>>Yes, it is included in Fortran 90.
>>Many compilers give the same effect with a command line option, e.g.,
> 
> Also, many f77 implementations use "IMPLICIT UNDEFINED A-Z", as 
> documented in the original f77 paper.  I just thought I'd mention this
> since I've heard people complain that, say, IBM RT f77 had "no way to
> force declaration" - just because it has IMPLICIT UNDEFINED rather than
> IMPLICIT NONE...!
> 

A trick that I've heard for forcing declarations in f77 is to come up with
a standard such as all LOGICALs must begin with Q.  Then declare

  IMPLICIT LOGICAL A-P,R-Z
  IMPLICIT REAL Q

This will work pretty well if you don't use a lot of LOGICALs.  Of course,
it would work best to choose the letter least likely to be used for a
variable name to choose as the IMPLICIT LOGICAL.  This is a kludge, but
might be handy to some.


Jeff Haferman                            internet: jlhaferman@icaen.uiowa.edu
Department of Mechanical Engineering
University of Iowa
Iowa City IA  52240