Re: Non-destructive record update??

From: Christophe Raffalli (craff@lama-d132.univ-savoie.fr)
Date: Sat Apr 25 1998 - 13:26:43 MET DST

Message-Id: <199804251226.OAA01300@lama-d132.univ-savoie.fr>
To: Donald Syme <Donald.Syme@cl.cam.ac.uk>
Subject: Re: Non-destructive record update??
Date: Sat, 25 Apr 1998 14:26:43 +0300
From: Christophe Raffalli <craff@lama-d132.univ-savoie.fr>

I completely agree with that.

You can end up with a messy program when you want to update record in a =

functional way. Moreover, if you add one field to a record type you have =
to =

modify your program for each updating even if they are unrelated with the=
new =

field !

The syntax could be

* x.y <- 2 (may be confusing with mutable syntax ?)

* let y = 2 in record x =

Or anything else, but there really should be something !

With the second syntax it is easy to extend the parser, =

and you could have a "and" to update more than one field, with only one c=
opy
of the original record:

let y = 2 and z = 3 in record x

This is not the case with the straight forward compilation of:

(x.y <- 2).z <- 3
=

-- =

Christophe Raffalli
Laboratoire de Mathématique / LAMA
Université de Savoie
UFR SFA, Campus Scientifique
73376, Le Bourget du Lac CEDEX, FRANCE.

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