Re: buffer question

On Thu, Apr 16, 2026 at 10:22 (-0400), Aditya Mahajan wrote:

> On Thu, 16 Apr 2026, Jim via ntg-context wrote:

>> So... is there some way to get a parameter value (pageHeight in this
>> example) into the buffer contents?

>> (I realize I can create Yet Another buffer MyPrePreamble which defines a
>> macro (or sets a dimen) to the desired value and call
>>         \typesetbuffer[MyPrePreamble,MyPreamble,content]
>> but I was wondering if there was something a bit more elegant.)

> Just do everything in lua:

> \starttext

> \startluacode
> local preamble = [[
>   \definepapersize[ShowAndTypeset]
>                   [width=%width%, height=%height%];
>   \setuppapersize[ShowAndTypeSet]
> ]]

> local options={width="5cm", height="10cm"}
> local parsed = utilities.templates.replace(preamble, options)

> context.tobuffer("MyPreamble", parsed)
> \stopluacode

> \typebuffer[MyPreamble]

> \stoptext

Aditya,

too easy!   Thanks.

(Is the ';' after "%height%]" really desired here, or did you pull yourself
away from a Algol/C/C++/Java program to answer this?)



Aditya presciently anticipated (is that redundant?) Question 3 of
International Buffer Day, which was going to be

Q3: How to create a buffer from inside a macro?

Given Aditya's answer to Q2, the solution is pretty simple:

\def\makeMyPreamble #1
{
    \startluacode
        local preamble3 = [[
            \definepapersize[ShowAndTypeset]
                            [width=100mm, height=#1]
            \setuppapersize[ShowAndTypeset]
        ]]
        context.tobuffer("MyPreamble", preamble3)
    \stopluacode
}

How to specify both width and height is left as an exercise to the diligent
student.  ;-)

                              Jim
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : [email protected] / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
webpage  : https://www.pragma-ade.nl / https://context.aanhet.net (mirror)
archive  : https://github.com/contextgarden/context
wiki     : https://wiki.contextgarden.net
___________________________________________________________________________________