Re: Analyzing Scheme source code

[Per Bothner <per@bothner.com>]

On 12/8/20 6:32 PM, Duncan Mak via Kawa wrote:
> I started writing my own analyzer with the match macro, and it looks
> something like this:
> 
> (define (process-form form)
>    (match form
>      (['define [name @args] @body]
>       (cons name (map process-form body)))
>   ... etc ...

That would not handle macros or imports, without a lot of effort.

> Thinking a bit more, rather than doing it myself, I thought maybe I could
> reuse the existing machinery that's in Kawa already,

I think that is a better way to go, though it would need internal undocumented APIs.

There is a non-documented kawa.expressions library (kawa/lib/kawa/expressions.scm),
though it is current mostly used for optimizing map and some other procedures.
See compile_map.scm and compile_misc.scm for uses.

To scan for uses, define a sub-class of ExpVisitor or ExpExpVisitor
looking for ReferenceExp.

For a more ambitious approach, one could beef up KawaLanguageServer,
and use existing clients/IDEs.

> For example, it'd be useful to see (define-record-type ...) forms too,
> right now, I don't know how to get at them.

Compiling a sample program with --debug-print-expr lets you see the
Expression tree generated for the program.

> Also, I can't quite figure out how to open up the inside of a Declaration
> either -- I'm looking for a getBody() method that might give me an
> Expression[], but I haven't been able to find any methods of that sort.

A Declaration is the "symbol" being defined.  The form in the source code
that does the defining is usually a SetExp (if at top-level).
It is possible to map from Declaration to defining expressions, but it
includes assignments (since it is used for optimization), and is rather
complicated.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/