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000004_icon-group-sender _Fri May 12 12:35:09 2000.msg
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by baskerville.CS.Arizona.EDU (8.9.1a/8.9.1) id MAA06563
for icon-group-addresses; Fri, 12 May 2000 12:34:57 -0700 (MST)
Message-Id: <200005121934.MAA06563@baskerville.CS.Arizona.EDU>
From: "Frank J. Lhota" <NOSPAM.Frank.Lhota@lexma.meitech.com>
X-Newsgroups: comp.lang.icon
Subject: Re: Is Anyone Working On A Unicode Version Of Icon?
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I would agree that it is much easier to add a new primitive type to the Java
implementation of Icon, as opposed to the C implementation. In either case,
however, adding a new primitive type involves coding in a language other
than Icon. Ideally, it would be nice to be able to write a new type, along
with its associated primitive operations, in Icon.
Currently, Icon permits one to define a new type with a record declaration,
such as
record Unicode_cset( ... )
A programmer can then define procedures for the new record type. A record
type, however, fails to extend the set of primitive types, for the following
reasons:
1. You cannot (re)define the primitive operators, such as "*", "++", or
"<<", for a record type;
2. You cannot define implicit /explicit type conversions between a record
type and the existing types; and
3. You cannot define the behaviour of functions such as image and write
for the new record type.
Now imagine that we modify Icon so that we could define operators, type
conversions, etc. for user-defined Icon types. Would this give us a
"pluggable" capability, similar to Squeak?