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Re: text functions in MathML

From: Stan Devitt <jsdevitt@stratumtek.com>
Date: Thu, 8 Aug 2002 17:24:50 -0400
Message-Id: <200208082124.LUG06279@vmms6.verisignmail.com>
To: Herman Schenck <herman@velosel.com>
Cc: "'www-math@w3.org'" <www-math@w3.org>

There was a conscious decision in the 
working group to leave string operations 
to the "extension" mechanism. In particular 
we also left out  programming constructs such as 
assignments, loops and conditionals.

A main early goal was to keep the recommendation 
focused on the passive representation of 
basic algebraic constructs. There
are perfectly good string algebras,
of course.

Your question implicitly raises the
question of whether the content of 
<ci>abc</ci> is treated as atomic or not?
Yes and No answers are both acceptable.

If the ci elements are regarded as 
the alphabet symbols then 

    concat( "a" , "b" , "c" )

could be written

<apply><times definitionURL="stringop" />
<ci>a</ci>
<ci>b</ci>
<ci>c</ci>
</apply>


Alternatively, we could view the ci tags like string
delimiters (with extra restrictions on the content of
the ci) and then 

   concat( "abc" , "def" ) 

could be written.

<apply>
<csymbol definitionURL="concat"/>
<ci>abc</ci>
<ci>def</ci>
</apply>

and 

substring( "abc" , 0 , 2 )  // "ab"

would be

<apply>
<csymbol definitionURL="substring"/>
<ci>abc</ci>
<cn>0</cn>
<cn>2</cn>
</apply>

Ideally, the definitionURL's would point to where such
design decisions were documented.

Both examples are valid MathML.  

Stan Devitt

---- Original message ----
>Date: Thu, 8 Aug 2002 13:09:20 -0700 
>From: Herman Schenck <herman@velosel.com>  
>Subject: text functions in MathML  
>To: "'www-math@w3.org'" <www-math@w3.org>
>
>
>I have been looking to extend MathML to handle text functions
like
>"substring" and "concat".  
>
>Is there any accepted way of doing this?
>
>One problem I see is that string constants do not have their
own tag.
>
>Thanks,
>
>-herman
>
Received on Thursday, 8 August 2002 17:24:52 GMT

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