Thanks for getting back to me on this.
The kind of thing I had in mind was to be able to type:
(iU (i n) (Person (index name i)))
as source code into Dr Racket. Once the closing parenthesis on the form was
typed, the editor would recognise the form as special and redisplay it as
$\bigcup_{i\in[0,n]} (Person (index name i))$. In principle, the format of the
input could be flexible, for example:
!(i n) (Person (index name i)))
Could have the same effect if it would be more convenient to get the processing
done via some character macro in the reader.
In a super-duper ideal world, once recognised and displayed in the math-style
with subscripts, the identifier names used in the subscript would be editable
in-place (via some form of selection and/or mouse navigation). However, I think
it would be acceptable for the projected form to revert to the AST
text-representation when it is selected for editing.
Regarding macro-expansion: I am not certain, but assume that the macro
expansion occurs after the forms in a DrRacket pane have been fully read.
Projectional Editors should ideally recognise the input and perform the
conversion to the 'projected' output format in-place as the text is typed. I
guess I could be completely wrong on that, in which case macro-expansion could
help 'catch' the input form and convert to the output form (but would need to
grab access to the underlying graphics for the editor surely?).
I don't think that a separate window<%> object would be acceptable, it needs to
integrate with the 'normal' editor as presented in DrRacket.
-- Tony
From: Robby Findler
<ro...@eecs.northwestern.edu<mailto:ro...@eecs.northwestern.edu>>
Date: Friday, 5 July 2013 14:26
To: Tony Clark <t.n.cl...@mdx.ac.uk<mailto:t.n.cl...@mdx.ac.uk>>
Cc: "users@racket-lang.org<mailto:users@racket-lang.org>"
<users@racket-lang.org<mailto:users@racket-lang.org>>
Subject: Re: [racket] Projectional Editors
I think DrRacket has all of the tools necessary to do what you're asking, but
there is no convenient API for putting it all together. Depending on how you
wanted it to look, I'd offer different suggestions on how to get started, I
guess. For example, if you're happy with the projections being in a separate
window<%> object, that'd be the easiest thing, I guess (and much of the work
you'd do could be re-used if you wanted a different way to draw it, with a
little bit of planning).
Are you thinking of using the raw source code to get the projection, or are you
planning to involve macro expansion?
Robby
On Fri, Jul 5, 2013 at 2:52 AM, Tony Clark
<t.n.cl...@mdx.ac.uk<mailto:t.n.cl...@mdx.ac.uk>> wrote:
Dear All,
I am implementing a language that involves patterns over sets. I am
experimenting with an 'indexed set' pattern of the form:
(iU (index-var limit-var) pattern …)
Where pattern can include constants, (indexed) variables, (indexed) sets and
terms. For example:
(iU (i n) (Person (index name i)))
Matches a set of terms:
'((Person fred) (Person bert) (Person sally))
To produce a binding environment:
'((n . 2) (name-0 . fred) (name-1 . bert) (name-2 . sally))
My question is whether DrRacket can be extended with 'projectional editing'
features so that:
(iU (i n) (Person (index name i)))
When entered, is displayed using the equivalent of latex:
$\bigcup_{i\in[0,n]} (Person (index name i))$
A projectional editor (http://martinfowler.com/bliki/ProjectionalEditing.html)
works by representing the AST of a language and then providing the user with a
view of the AST, thereby allowing fancy representations. Whether the user can
interact with the fancy representation or has to work at the AST level depends
on the projectional editor.
I think DrRacket ought to be ideal for this kind of thing since: (a) we are
essentially working on an AST already; (2) the editor appears to be
programmable; (3) the GUI libraries allow easy dynamic creation of images that
can be inserted into the editor.
I looked at the reference for DrRacket Plugins, but encountered a large
interface that I am unsure how to navigate.
Thanks for any pointers.
-- Tony
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handler, CDS, and then emailed to the recipient.
If you do not want your correspondence to Middlesex University processed in
this way please email the recipient directly. Parcels, couriered items and
recorded delivery items will not be opened or scanned by CDS. There are items
which are "exceptions" which will be opened by CDS but will not be scanned a
full list of these can be obtained by contacting the University.
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