[Om] Named functions in OpenMath

Wenzel, Ken Ken.Wenzel at iwu.fraunhofer.de
Mon May 4 12:31:57 CEST 2015


Thank you for your explanation.

So I should use fns1.lambda to bind the variable $area within "context".
But, if i like to use $area outside of "context" then I have to resort to the symbols
in prog1 like prog1.assignment and prog1.local_var.

So if I like to have a global reference to a function named area like
http://openmath.org/fns/area
then this is only supported by structural sharing using the
id and href mechanisms of OpenMath?

Best regards,
Ken
________________________________________
Von: James Davenport [J.H.Davenport at bath.ac.uk]
Gesendet: Montag, 4. Mai 2015 11:45
An: Wenzel, Ken
Cc: om at openmath.org
Betreff: Re: [Om] Named functions in OpenMath

I am not sure that I am familiar enough with Popcorn to understand the
details, but I'll try.
What you seem to want is a context in which 'area' is fns1.lambda[$a,
$b -> $a * $b].
This is, I claim, conceptually no different from a context in which
'area' is 42.
An old-fashioned function programmer might apply fns1.lambda[$area ->
context] and apply it to 42 (or fns1.lambda[$a, $b -> $a * $b]) , but
this is ratehr in need to syntactic sugar.
Have you looked at the prog1 CD, which might be what you want.
James
Quoting "Wenzel, Ken" <Ken.Wenzel at iwu.fraunhofer.de>:

> Hello,
>
> I wonder what is the correct way to represent a named function in OpenMath.
>
> For example, I like to describe a function named "area" that computes the
> area of a rectangle.
>
> The corresponding Popcorn expression for the anonymous function is:
>
> fns1.lambda[$a, $b -> $a * $b]
>
> What is now the correct method to name this function.
>
> I can, for example, just give it an ID like
>
> fns1.lambda[$a, $b -> $a * $b] : area
>
> and invoke it with #area(3, 4) at an later point.
>
> But I think this is some kind of structure sharing since the lambda
> expression is
> simply copied into the resulting OpenMath object and not the invocation of
> a single function named "area".
>
> I would be grateful if somebody can help me.
>
> Best regards,
> Ken
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James Davenport
National Teaching Fellow 2014
Hebron & Medlock Professor of Information Technology, University of Bath
OpenMath Content Dictionary Editor
Director of Studies EPSRC Doctoral Taught Course Centre for HPC
Chair, IMU Committee on Electronic Information and Communication
Vice-President and Academy Trustee, British Computer Society
SW Coordinator, Computing at School Network of Excellence



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