mailing-list for TeXmacs Users

[Joris van der Hoeven <address@hidden>]

On Wed, Oct 01, 2008 at 08:44:09AM +0100, Duncan Smith wrote:
> To try and understand I've been looking at the docs and src code a
> little more it seems that for tags like sqrt or frac then you can
> manipulate the tree in a plug-in converter

Yes, because a tree is already in a parsed state.

> but for a simple symbol like "<neq>" there is no tree so you
> can only substitute the symbol itself for other text.

Yes, otherwise I would have to parse the expression.

> 
> Assuming there's no way to manipulate the input or math tree from
> within the neq converter, then I guess the best you can do is to
> subst.
> '<neq>' for 'is(not(equal('
> 
> Then call it at the input prompt like:
> 
> (%i1) <neq>1,2))
> 
> which seems a shame compared to the more natural
> 
> (%i1) 1 <neq> 2
> 
> if only because both operands must be placed after the neq symbol and
> there's an asymmetric number of parenthesis left on the input line.

Yes, I don't see any easy way out.

> I'm sorry I didn't understand your suggestion about replacing neq for
> a maxima lambda function since the goal was to use the graphical
> symbol in the middle of the two operands for input.

You would need a lambda expression which is considered as an infix operator.
I don't know whether this is supported by Maxima (probably not, indeed).

Best wishes, Joris