#1144: MMD incorrectly matches _ instead of String
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Reporter: Austin_Hastings | Type: bug
Status: new | Priority: normal
Milestone: | Component: none
Version: 1.7.0 | Severity: medium
Keywords: | Lang:
Patch: | Platform:
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Comment(by Austin_Hastings):
After bouncing off this problem again, and doing some further
investigation, I've learned that:
`mmd_distance` (src/multidispatch.c ~ line 770-790) explicitly checks if
the args to the call are "int,float,string" and the callsig wants
"Int,Float,String", and assigns that promotion a distance of 1.
`mmd_distance` then, _immediately_, checks if the args to the call are
"any basic type" and the callsig wants "PMC" (aka '_'), in which case the
distance is 1.
On the one hand, this is two ways of saying that "boxing has a distance of
1". But on the other hand it means that when you pass a 'string'
(lowercase) to a (String) or to a (_) multisig, they both have a distance
1.
What I was trying to achieve with (_) was "if you haven't matched anything
closer, use this error case". To this end, I think that while
constant->PMC should not be "big distance", it should probably be greater
than just 1.
--
Ticket URL: <https://trac.parrot.org/parrot/ticket/1144#comment:1>
Parrot <https://trac.parrot.org/parrot/>
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