[racket] Projectional Editors

From: Tony Clark (t.n.clark at mdx.ac.uk)
Date: Fri Jul 5 03:52:10 EDT 2013

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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