Numeric read seems too strict

David Feuer david.feuer at
Wed Sep 14 18:18:21 UTC 2016

This may be true, but I don't see how it's relevant.

On Sep 14, 2016 2:14 PM, "Carter Schonwald" <carter.schonwald at>

> Read and show are supposed to be simple and perhaps at least have well
> behaved asymptotic performance , but ultimately are for simple debugging
> and or pasting back into source.  Granted it winds up also being used to
> serialize small config that are human manipulable or easy to paste back
> into source
> On Sep 12, 2016 2:03 PM, "David Feuer" <david.feuer at> wrote:
>> By the way, I believe we should be able to read numbers more efficiently
>> by parsing them directly instead of lexing first. We have to deal with
>> parentheses, white space, and signs uniformly for all number types. Then
>> specialized foldl'-style code *should* be able to parse integral and
>> fractional numbers faster than any lex-first scheme.
>> On Sep 12, 2016 1:53 PM, "David Feuer" <david.feuer at> wrote:
>> I noticed the other day that
>> readMaybe (fix ('a':)) :: Maybe Double
>> is an infinite loop. The problem is that the lexer doesn't know that it's
>> expected to lex a number. It just keeps scanning and scanning to get to the
>> end of the endless token. Shall we fix this?
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