[plt-dev] Re: [plt-bug] all/10233: error on RUN in BSL, apparently related to test engine

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Mon May 11 10:45:23 EDT 2009

I dropped bugs since this is not the same bug as the original PR.

The problem appears to be a combination of the way big-bang expands
and the way test coverage works. Here's a shorter program that I think
illustrates this a little bit better:

;; BSL:
(require 2htdp/universe)
(define (clack ws x y action) 1)
(define (main s) (big-bang s (on-mouse clack)))
(clack 5 3 2 "leave")

In this program, you see the identifier 'clack' in the definition of
clack highlighted, as well as the 's' in the body of main.

This is almost right -- the correct thing would have been to highlight
the 'clack' in the argument to on-mouse instead of the other clack.

Is it possible that the big-bang macro is doing somethign clever with
source locations that confuses the test coverage?

FWIW, the test coverage is simply updating some state somewhere with
source location ranges in the editor and then coloring things based on
what was executed in the fully expanded program. Perhaps it is worth
looking at 'big-bang' and thinking about how source locations of
syntax objects flow thru that expansion in those terms?


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