Bruce,
Get well!
You may find you end up being the expert on scheme to Unicon!
Since you had some nested lambda's going on then I suspect once you crack that
you may be able to solve Y. I've only been looking at it over coffee and in
waiting rooms - not enough to get my head around the mechanics of it (below).
I can follow it and almost see it but I have no feeling for what scheme is
doing under the covers.
(define (Y f)
((lambda (x) (x x))
(lambda (x) (f (x x)))))
(define factorial (Y almost-factorial))
If you do I'd love to hear.
David
>________________________________
> From: Bruce & Breeanna Rennie <[email protected]>
>To: [email protected]
>Sent: Wednesday, December 21, 2011 1:18:37 PM
>Subject: Re: [Unicon-group] What is the idiomatic way to represent Lambda
>function in Icon/Unicon
>
>
>Thank you David,
>
>I have just downloaded the last Generator issue and will look at
this later today. I much appreciate your direction and guidance on
this matter. It looks like I'll have something to read while
confined to my sick bed for today.
>
>regards
>
>Bruce Rennie
>
>On 22/12/11 01:47, David Gamey wrote:
>Bruce,
>>
>>
>>The call in every c(simpleMap(tree)) is the activation of co-expression c
>>using the new(er) procedural syntax.
>>
>>
>>This may help
>>http://rosettacode.org/wiki/Icon%2BUnicon/Intro#Co-expression_Flow
>>
>>
>>If you haven't already read it Steve's article in The Generator v2n2 Fun with
>>Co-expressions, part 2 explains this. There's links from RC's Unicon page
>>and the intro above.
>>
>>
>>
>>Sorry, I don't have time for a longer explanation today.
>>
>>
>>
>>
>>Other RC tasks that use may provide examples
>> * http://rosettacode.org/wiki/Accumulator_factory
>>
>> * http://rosettacode.org/wiki/Anonymous_recursion
>> * http://rosettacode.org/wiki/Closures/Variable_capture
>>
>> * http://rosettacode.org/wiki/Function_composition
>> * and as I mentioned there is a Y-combinator page but it hasn't been
>> solved for Unicon
>>
>>
>>
>>
>>
>>David
>>
>>
>>
>>
>>
>>
>>
>>
>>>________________________________
>>> From: Bruce & Breeanna Rennie <[email protected]>
>>>To: [email protected]
>>>Sent: Wednesday, December 21, 2011 6:24:47 AM
>>>Subject: Re: [Unicon-group] What is the idiomatic way to represent Lambda
>>>function in Icon/Unicon
>>>
>>>
>>>Thanks to both Steve and David for your respective pieces of information. I
>>>have been able to get a bit further into solving my problem which is
>>>translating the scheme interpreter for KERNEL (SINK) into Unicon/Icon. The
>>>reason for the translation is that SINK runs real slow.
>>>
>>>The next little problem, is finding a way to
generate lots of anonymous functions. I seem to
recall seeing something like that quite a few years
ago.
>>>
>>>The following scheme code gives the idea of what I
am translating. The following is an extract from
John Shutt's SINK file object.scm
>>>
>>>#; (define make-foo
>>>#; (lambda (bar quux)
>>>#; (let ((name (list #t)))
>>>#; (lambda (message)
>>>#; (case message
>>>#; ((type) 'foo)
>>>#; ((name) name)
>>>#; ((bar) bar)
>>>#; ((quux) quux))))))
>>>#;
>>>#; (define foo? (make-object-type-predicate
'foo))
>>>#;
>>>#; Sufficient accessors should be provided that
clients never have to know that
>>>#; encapsulated objects are dispatch procedures; for
example, if clients should
>>>#; have the ability to access the 'bar and 'quux
attributes of a foo,
>>>#;
>>>#; (define get-foo-bar (lambda (x) (x 'bar)))
>>>#; (define get-foo-quux (lambda (x) (x 'quux)))
>>>#;
>>>
>>>#;
>>>#; Determines whether all its arguments are objects.
>>>#;
>>>#(define object? procedure?)
>>>
>>>#;
>>>#; Given some number of symbol arguments, constructs
a predicate that takes
>>>#; an argument and determines whether it is an
object whose type is amongst
>>>#; the given symbols.
>>>#;
>>>#(define make-object-type-predicate
>>># (lambda types
>>># (lambda (object)
>>># (and (object? object)
>>># (pair? (member (object 'type)
types))))))
>>>
>>>The make-object-type-predicate is used to generate
anonymous functions.
>>>
>>>I have just another look at what you have written
Steve as below.
>>>
>>>
>>>procedure applyTests(tree, env, context) c := create repeat { operand :=
>>>(result@&source)[1] # allows function-style calls result := operand(env,
>>>context) # in case result is needed } @c # advances evaluation CE to
>>>'synchronization point', so next # value passed in gets assigned to
>>>operand. every c(simpleMap(tree)) # here, result is ignored
end
Would you mind explaining what is happening here. I think I have maybe
completely missed what is going on here. See if I have this right.
>>>
>>>result is a local variable with the initial value of &null
>>>result@&source simply returns control back to applyTests at the line @c
>>>
>>>What I stuck at is (and I thought I understood but
sure now I don't) the line
>>>
>>>every c(simpleMap(tree))
>>>
>>>What is actually happening here and how does this
relate to the code in the co-expression
>>>
>>>operand := (result@&source)[1]
>>>result := operand(env, context)
>>>
>>>I should be using Unicon much more but most of the
work I do these days is based on Microsoft Office
products as these are the tools that my clients run
and so it is VBA mostly.
>>>
>>>I think I need to get more stuff done in other
languages.
>>>
>>>Anyway back to the problem at hand. Would you mind
explaining in detail what is happening here, please.
>>>
>>>Clinton, would a extra section in your book be able
to be written on these kinds of subjects?
>>>
>>>regards
>>>
>>>Bruce Rennie
>>>getting slower as I age.
>>>
>>>
>>>
>>>
>>>
>>>------------------------------------------------------------------------------
>>>Write once. Port to many.
>>>Get the SDK and tools to simplify cross-platform app
development. Create
>>>new or port existing apps to sell to consumers
worldwide. Explore the
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>>>_______________________________________________
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>>>
>>>
>>>
>>
>>
>>------------------------------------------------------------------------------
Write once. Port to many.
Get the SDK and tools to simplify cross-platform app development. Create
new or port existing apps to sell to consumers worldwide. Explore the
Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
http://p.sf.net/sfu/intel-appdev
>>
>>
>>_______________________________________________
Unicon-group mailing list [email protected]
https://lists.sourceforge.net/lists/listinfo/unicon-group
>
>------------------------------------------------------------------------------
>Write once. Port to many.
>Get the SDK and tools to simplify cross-platform app development. Create
>new or port existing apps to sell to consumers worldwide. Explore the
>Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
>http://p.sf.net/sfu/intel-appdev
>_______________________________________________
>Unicon-group mailing list
>[email protected]
>https://lists.sourceforge.net/lists/listinfo/unicon-group
>
>
>------------------------------------------------------------------------------
Write once. Port to many.
Get the SDK and tools to simplify cross-platform app development. Create
new or port existing apps to sell to consumers worldwide. Explore the
Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
http://p.sf.net/sfu/intel-appdev
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