[REBOL] Fwd: Re: Re: On mutability and sameness
From: robbo1mark:aol at: 19-Jun-2001 12:40
sorry if you receive this twice - AOL playing up today!
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Date: Tue, 19 Jun 2001 12:35:19 EDT
From: [Robbo1Mark--aol--com]
Subject:Re: [REBOL] Re: On mutability and sameness
To: <"[rebol-list--rebol--com] ; Oscar-Project"@egroups.com>
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Everybody,
consider these examples of any-block! values
>> a: load "( 1 + 2 )"
== (1 + 2)
>> :a
== (1 + 2)
>> parse :a [b:]
== false
>> b
== [1 + 2]
>> a: make hash! [ add 3 4 ]
== make hash! [add 3 4]
>> parse :a [b:]
== false
>> b
== [add 3 4]
>> insert b 'negate
== [add 3 4]
>> b
== [negate add 3 4]
>> a
== make hash! [negate add 3 4]
>> a: make list! [ power 3 4 ]
== make list! [power 3 4]
>> parse :a [b:]
== false
>> b
== [power 3 4]
It seems that we can make instances of the same any-block!
data values even though the block!s are of different datatype!
eg Paren! Block! Hash! List! etc.
These too can be modified and changes to either effect both.
So for series! values we seem to have only 2 base implementation
models which are any-block! and any-string!, the rest are simply
a change in the datatype! field.
My model for series values has 4 fields which are
series.datatype
series.length ; Total number of values not length from index to tail
series.index ; the current series position
series.value ; the actual "data" values of the series which can be
; of any-type! for any-block! series and of
; char! for any-string! series.
I hope you find this model and examples helpful and instructive, I cannot
guarentee that this model is entirely accurate or complete, only that it's
seems to work at present.
Hopefully my friendly neighbours will help me "paint my fence" by helping
to show where this model breaks or is incomplete.
Cheers my REBOL friends ( of whom I sincerely hope includes Jeff & Holger
even though we may not always be in complete agreement! )
For the record Monet & Van Gogh are my favourite painters.
Impressionists of course! 8-)
Mark Dickson
