#5688: instance Read Integer/Rational/Double readsPrec out of memory and crash
due
to exponential notation
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Reporter: gracjan | Owner: igloo
Type: bug | Status: new
Priority: highest | Milestone: 7.4.2
Component: libraries/base | Version: 6.12.3
Resolution: | Keywords:
Os: Unknown/Multiple | Architecture: Unknown/Multiple
Failure: Runtime crash | Difficulty: Unknown
Testcase: | Blockedby:
Blocking: | Related:
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Comment(by maeder):
The precise number given by the input string needs to be converted to the
nearest representable number (by the round-to-nearest rule of IEEE 754
floating-point arithmetic).
If we assume that `fromRational` does this correctly, it is enough to
roughly estimate when the value will definitely be +/- Infinity/Zero (in
order to avoid computing an overly large Rational value causing this
ticket).
Roughly estimating makes failing inconsistent (at least not precise).
It remains to check, if `fromRational` does the right thing. I assume it
replaces "%" by "/" and converts the two arguments from Integer to
Double/Float first. (Where is the code for this?)
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5688#comment:47>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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