[racket] module browser

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Thu May 24 17:00:26 EDT 2012

I wonder whether an approximate tool would be just fine for now, especially if it listed things that it didn't understand. 

On May 23, 2012, at 4:04 PM, Ryan Culpepper wrote:

> On 05/23/2012 12:31 PM, Neil Van Dyke wrote:
>> Thanks, Ryan, that info is helpful, although it's missing most of the
>> reasons I've had to partition one library into several modules (macro
>> transformers).
>> As people have mentioned before, there seems to be a theoretical brick
>> wall preventing these tools from seeing references that likely will be
>> used in the results of macro transformations. I don't understand that in
>> all cases. For one example, the transformers often have templates that
>> should know many of the symbols and exactly where they're coming from.
>> (Is this information from templates lost too soon? Is the information
>> from templates not as precise as I assumed?)
> IIRC, 'check-requires' does in fact inspect syntax templates. The problem is that it's not possible to predict in what phase(s) the identifiers in a syntax template will be interpreted.
> For example, consider this module:
> (module AMB racket
>  (require (for-template (rename-in racket/base [- shifty]))
>           (only-in racket/base [+ shifty]))
>  (define shifty-stx #'(shifty 1 2))
>  (provide shifty-stx))
> Does the occurrence of 'shifty' in the syntax template refer to '+' or '-'? It might be both.
> If it's used in a macro, 'shifty' means '-':
>  (require (for-syntax 'AMB))
>  (define-syntax m (lambda _ shifty-stx))
>  (m)
>  ;; => -1
> but if it's evaluated with 'eval', 'shifty' means '+':
>  (require 'AMB)
>  (eval shifty-stx (make-base-namespace))
> (Exercise: add (require (for-meta 2 (rename-in racket/base [+ shifty]))) to AMB. See if you can construct a program that interprets 'shifty' as '*'.)
> --
> But I'd estimate that 90% of the time, an identifier in a syntax template is interpreted at the phase one less than the phase the syntax template occurs in. And 90% of the remaining cases it's interpreted in the same phase as the syntax template. So that's what 'check-requires' assumes (see 'analyze/quote-syntax' in macro-debugger/analysis/private/get-references).
> If 'check-requires' isn't seeing dependencies from syntax templates, can you send me an example?
> > For another example (or
>> possibly the same thing), these tools seem to be missing references in
>> the code of "syntax-parse" productions that is outside templates and
>> that I'd think is unambiguous.
> I don't understand what you mean. Can you give an example?
> Ryan
>> BTW, a student who is bored over the summer could do worse than to
>> enhance the Module Browser in some other ways. First low-hanging fruit
>> step might be to put the information from "check-requires" into tooltips
>> on the arrows. Then there's a lot one could do with graph drawing. And,
>> as a small graphics tweak, you can make it skip redundant repaints
>> queued up when dragging. (Summer is good for this. More than a little
>> sun exposure will just age your skin prematurely and give you melanoma,
>> anyway.)
>> Neil V.
>> Ryan Culpepper wrote at 05/23/2012 02:28 PM:
>>> On 05/23/2012 11:13 AM, Neil Van Dyke wrote:
>>>> In the Module Browser, has anyone tried annotating the graph edges with
>>>> imported symbols that are actually referenced by the importing module?
>>>> Maybe further annotate those symbols with phases?
>>> You can get this information (in text form) from the check-requires
>>> utility. You may find the code in
>>> macro-debugger/analysis/check-requires (and its dependencies) useful
>>> if you want to add this information to the module browser. Getting the
>>> set of references is actually somewhat tricky, and I think my code
>>> does as good a job as possible.
>>> Ryan
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