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From: gaertner@tertius.in-berlin.de
Newsgroups: comp.lang.pascal
Subject: Re: arrays
Message-ID: <1991Jun20.094704.6589@tertius.in-berlin.de>
Date: 20 Jun 91 09:47:04 GMT
References: <1991Jun18.175558.1667@odin.corp.sgi.com>
Lines: 35

In article <1991Jun18.175558.1667@odin.corp.sgi.com>, avila@swinger.csd.sgi.com (Richard Avila) writes:
> In pascal on the SGI box a user wanted to create
> an array type such that at compile time the
> bounds ( or size of the array ) is not known.
> 
> Then at runtime the bounds can be assigned
> and the variable is created.
> 

The current Pascal definition allows only data types which must be known at
runtime.
There is a new Pascal standard (Extended Pascal) under development/revision (?)
which allows the dynamic assignment of bounds (as I know). This Extended
Pascal has been published by IEEE (sorry, I don't know the catalog number)
and may be submitted to approval to ISO.
The VAX Pascal implements a lot of the features of this Extended Pascal, so the
following example has been taken from the VAX/VMS Pascal Language Reference
Manual. It shows the usage of the so called `Schema Types':

TYPE
  Array_Template(Upper_Bound : INTEGER )
                = ARRAY[1..Upper_Bound] OF INTEGER ;
VAR
  Array1 : Array_Template( 10 ) ; { ARRAY[1..10] OF INTEGER ; }
  Array2 : Array_Template( x )  ; { Upper bound determined at run-time by
                                    variable or function call ; }

I hope that this Extended Pascal will be available on a lot of machines soon.

Ralf

---

  Ralf Gaertner                  gaertner@venus.rz-berlin.mpg.de
  FHI Berlin