[Pharo-dev] Phexample: API Change Proposal (was Phexample: Image Destroying Bug)

Sean P. DeNigris sean at clipperadams.com
Tue Apr 22 10:40:59 EDT 2014


Reverting EyeInspector>>#updateList revealed the error when Phexample is used
in latest Pharo 3.0...

PhexMatcher uses #= as part of it's DSL e.g. "1 should = 1". Because it
doesn't respond normally to #=, #hash is implemented to signal an error
(self error: 'Don''t put a matcher into a dictionary. It does not behave
ordinarily on ='). I guess the receiver inspector on the bottom left of the
debugger keeps the items in a dictionary, so #hash gets called and
everything blows up.

The first thought that comes to my mind is that #= is "too cute" as a DSL.
#= is too deep of a smalltalk concept to justify hijacking, AFAICT to avoid
writing equals:.

I removed #= and #hash from PhexMatcher, adding an #equals: with the former
#= implementation, and everything seems to work.

I don't have write access to
http://smalltalkhub.com/mc/Phexample/Phexample/main/ and realize it's a big
API change, so I committed the fix to
http://smalltalkhub.com/mc/SeanDeNigris/SeansOutbox/main/ :
Name: Phexample-SeanDeNigris.71

MAJOR API CHANGE:
- change matcher #= to #equal: e.g. "1 should = 1" would now be written "1
should equal: 1"
- update all code to use new API

Motivation: the #= magic made it impossible to store matchers in
dictionaries, and #hash was implemented to signal an error explaining as
much. Unfortunately, #= and #hash are deeply ingrained Smalltalk concepts,
and are assumed to work as expected. In Pharo 3.0, the debugger tried to put
matchers in a dictionary, causing an infinite error loop whenever a matcher
failed.



-----
Cheers,
Sean
--
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