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[Giovanni Piredda <address@hidden>]

Hi Max,

I think I understand it now (I will try it tomorrow). Thanks for the 
explanation.

I have a memory of seeing a procedure that finds out if a tree is inside 
a math environment, and that I have even tested it, but I need to find 
it again.

Perhaps that is the way to achieve what I would like to achieve 
(typesetting something in a way that depends on where it is, and not in 
a way that depends on where *the cursor* is), but I first need to find 
it again in the documentation).

G.


On 18.11.20 00:32, Massimiliano Gubinelli wrote:
> As an example, try to use my macro and then create an equation and enter it with the cursor, then make "Update all" 
> (Shift+Cmr+R) and you will see that the value of all the instances of the macro will change to "+++". If now you go 
> with the cursor on the text and then you do again "Update all", then all the instances change to "xxxx". 
> This depends where the cursor is, not where the macro are called. And "Update all" just force TeXmacs to rexpand all 
> the document from the start.
>
> Best
> Max
>
>
> > On 18. Nov 2020, at 00:29, Massimiliano Gubinelli <address@hidden> wrote:
> >
> > Dear Giovanni,
> > my understanding of the matter can be wrong (or not totally correct) however 
> > is as follows:
> >
> > 1) In order to display your document, TeXmacs need to transform the document 
> > tree into a series of boxes which indicate where and what put on the screen 
> > or on the paper. This transformation go thru several phases, one of which is 
> > the macro expansion phase, i.e. markup in the document is evaluated until 
> > primitive markup is reached, which then allows to compute boxes and the 
> > material which will eventually end up on your screen.
> >
> > 2) Every time the document is modified, for example by the user editing it 
> > inserting some text in some position of the document tree, TeXmacs perform 
> > the computations in 1) to transform the modified document tree into a new 
> > sequence of rendering instructions.
> >
> > 3) If you put some \extern markup in the document, then when TeXmacs tries to 
> > expand that markup it (by definition) goes on by calling the scheme procedure 
> > and replacing the \extern markup with the result of the scheme procedure. 
> > Now, the scheme procedure does not have *any* informations on where the 
> > \extern markup was in the document tree. So scheme cannot know if we were in 
> > an equation or in a piece of text.
> >
> > Your confusion is to believe that in-math? returns true in a situation where 
> > you use \extern inside an equation. This is not true, in my understanding.
> >
> > in-math? is true only if the *editor* is in math mode, that is your cursor is 
> > inside an equation. This is a global mode of the editor and if it happens 
> > that your macro is evaluated again at that moment, then the predicate returns 
> > true, but this does not depend on the position of your \extern in the 
> > document tree, but on the current position of the cursor at the moment 
> > TeXmacs tries to recompute that part of the tree.
> >
> > Maybe this description is not totally correct (I'm not sure how and when 
> > exaclty TeXmacs goes to a reexpansion of the macros) but seems coherent with 
> > the bizzare behaviour of your macros.
> >
> > Also try \extern with a procedure of the form
> >
> > (define (myfunc) (if (in-math?) "+++" "xxxx")))
> > to see how, even when you put it in regular text, you can have "+++" if, 
> > right away you then enter into math mode.
> >
> > HTH,
> > Max
> >
> >
> >
> > > On 17. Nov 2020, at 23:29, Giovanni Piredda <address@hidden> wrote:
> > >
> > > I am going to answer your previous message (thanks for that by the way) but 
> > > before that: I do not follow the explanation in this message on the in-math? 
> > > predicate, I have an idea of what you might mean, but maybe the idea is wrong 
> > > :-)
> > >
> > > Let me write it down here.
> > >
> > > Starting from:
> > >
> > > "As I open the file, where I have the macro (which calls Scheme code via 
> > > extern) both inside math and outside math, they are all executed as if in text 
> > > mode.
> > >
> > > If I edit one of them, now the predicate in-math? has effect."
> > >
> > > you say that when I open the file TeXmacs is only typesetting (and therefore 
> > > uses the default function, as (in math?) returns always #f), but when I am 
> > > editing TeXmacs knows what I am editing and lets Scheme know. Is it that?
> > >
> > > The follow-up question in this case is how can I obtain what I want, that is 
> > > a different function being called ever time the macro is executed, that is 
> > > also at the opening of the file. The aim seems sensible to me - typesetting 
> > > something in one way when in math and in one way when in text (as I said 
> > > above, now it is working when I write/edit, it is not working if I close and 
> > > open again a document).
> > >
> > > Besides, doing Document->Update all hangs the document for a one/two minutes 
> > > (Ubuntu 20.10, I observed it in another document too), makes the macros work 
> > > well (upright in math, no asterisks, so it is recognizing the math), which is 
> > > pretty surprising, but destroys the page setup (margins are lost).
> > >
> > > G.
> > >
> > >
> > > On 17.11.20 22:50, Massimiliano Gubinelli wrote:
> > > > Going back to your attempt: I think that the predicate in-math? cannot be 
> > > > used to check whether the typesetter is working on an equation or not. No 
> > > > information is passed to Scheme about the internal status of the typesetter 
> > > > when you call a \extern markup. You can pass informations only via 
> > > > parameters. So your unitSpacer has no way to know if the evaluation is inside 
> > > > some math markup or not.
> > > >
> > > > The predicates in-math?, etc.. are just to check if the editor is in text, 
> > > > prog, or math mode, for example. Thats is completely separate on the status 
> > > > of the typesetter.
> > > >
> > > > HTH,
> > > >
> > > > Max
> > > >
> > > >
> > > >
> > > > > On 17. Nov 2020, at 19:25, Giovanni Piredda <address@hidden> wrote:
> > > > >
> > > > > I post this here because I think that while being about Scheme in TeXmacs is 
> > > > > still of general interest. I have found a way of circumventing both issues 
> > > > > (which may be ok, in case I will ask about this in another post) but I am 
> > > > > curious to know the reason of the behaviours I observe.
> > > > >
> > > > > First issue.
> > > > >
> > > > > I have defined a Scheme function with the following:
> > > > >
> > > > > (tm-define (unitSpacer) ; default, will be used in regular text
> > > > >        `(hspace "0.5spc"))
> > > > > (tm-define (unitSpacer)
> > > > >        (:require (in-math?))
> > > > >        "*")
> > > > >
> > > > > As far as I understand, the first definition is the default and it is 
> > > > > overridden by the second when I am in math.
> > > > >
> > > > > In my tests, this happens only in open documents. At the first opening of a 
> > > > > document, only the first definition is used. Does anyone have a hint on what 
> > > > > is happening? Developers ;-) ?
> > > > >
> > > > > ===
> > > > >
> > > > > Second issue.
> > > > >
> > > > > In math mode, the program I wrote outputs groups of letters, each wrapped in a 
> > > > > <with|math-font-shape|right primitive, and interleaved with the character "*".
> > > > >
> > > > > Example of output, copied from the terminal using (display ...)
> > > > >
> > > > > <tree 2 <with|math-font-shape|right|kg>*<with|math-font-shape|right|m>>
> > > > >
> > > > > I call this from a TeXmacs macro in math mode and I get a typeset output 
> > > > > where the asterisk appears as such (while I would like it to be interpreted 
> > > > > as an implicit multiplication)
> > > > >
> > > > > If I copy the output from the terminal, strip the outermost <tree primitive 
> > > > > and place it inside a math primitive (opening the .tm file with a text editor) 
> > > > > the asterisks do not appear (as I thought they shouldn't).
> > > > >
> > > > > Again, suggestions?