On 24/09/11 05:21, Evan Laforge wrote:
hex2 = (+)$ ((*16)$ higit)* higit
higit = subtract (fromEnum '0')$ satisfy isHexDigit
color = Color$ hex2* hex2* hex2
How is subtract (fromEnum '0') supposed to convert a hex digit to an
Int or Word8? I think you need digitToInt (or an equivalent
Evan Laforge wrote:
hex2 = (+)$ ((*16)$ higit)* higit
higit = subtract (fromEnum '0')$ satisfy isHexDigit
color = Color$ hex2* hex2* hex2
Twan van Laarhoven wrote:
How is subtract (fromEnum '0') supposed to convert a hex digit to an Int
or Word8? I think you need digitToInt (or an
Suppose we want to parse a 24-bit hex color value:
input :: ByteString
input = af093c blah blah blah
type Color = (Word8, Word8, Word8)
Attoparsec.Char8 exports a nice hexadecimal parser, but it consumes all
available hex-flavored input. I'd like to make it consume exactly two bytes,
so I
On Fri, Sep 23, 2011 at 8:04 PM, Michael Craig mks...@gmail.com wrote:
Suppose we want to parse a 24-bit hex color value:
input :: ByteString
input = af093c blah blah blah
type Color = (Word8, Word8, Word8)
Attoparsec.Char8 exports a nice hexadecimal parser, but it consumes all
available
BTW you probably want 'data Color = Color !Word8 !Word8 !Word8'
On Fri, Sep 23, 2011 at 8:21 PM, Evan Laforge qdun...@gmail.com wrote:
On Fri, Sep 23, 2011 at 8:04 PM, Michael Craig mks...@gmail.com wrote:
Suppose we want to parse a 24-bit hex color value:
input :: ByteString
input = af093c
I agree on all counts! The hex-handling logic here is so straightforward
that it's hardly worth bothering with. In fact, my application's code as it
stands looks very similar to what you wrote. I'm really asking because I
want to be more fluent in attoparsec.
So the question remains: is there a
So the question remains: is there a way to limit a parser to a finite chunk
of input? Perhaps a way to run the 'take n' parser on the input and then run
another parser on its result? This smells like monadic behavior, but of
course with different semantics than the Monad instance for Parser.
