Adjust a reading function to recognize an optional leading sign. As with the other functions, we assume an ASCII-compatible encoding of the sign characters.
Modulebytestring-lexing-0.5.0.16Haskell2010
Data.ByteString.Lex.Integral
Functions for parsing and producing Integral values from/to ByteStrings based on the "Char8" encoding. That is, we assume an ASCII-compatible encoding of alphanumeric characters.
Since: 0.3.0
Synopsis
- value readSigned
- value readDecimal
- value readDecimal_
- value packDecimal
- value readHexadecimal
- value packHexadecimal
- value asHexadecimal
- value readOctal
- value packOctal
- Packagebytestring-lexing-0.5.0.16
- Exports9
- LanguageHaskell2010
- LicenceBSD-3-Clause
- SourceIntegral.hs
General combinators
Decimal conversions
Read an unsigned/non-negative integral value in ASCII decimal
format. Returns Nothing if there is no integer at the beginning
of the string, otherwise returns Just the integer read and the
remainder of the string.
If you are extremely concerned with performance, then it is more
performant to use this function at Int or Word and then to
call fromIntegral to perform the conversion at the end. However,
doing this will make your code succeptible to overflow bugs if
the target type is larger than Int.
A variant of readDecimal which does not return the tail of
the string, and returns 0 instead of Nothing. This is twice
as fast for Int64 on 32-bit systems, but has identical performance
to readDecimal for all other types and architectures.
Since: 0.4.0
Convert a non-negative integer into an (unsigned) ASCII decimal
string. Returns Nothing on negative inputs.
Hexadecimal conversions
Read a non-negative integral value in ASCII hexadecimal format.
Returns Nothing if there is no integer at the beginning of the
string, otherwise returns Just the integer read and the remainder
of the string.
This function does not recognize the various hexadecimal sigils like "0x", but because there are so many different variants, those are best handled by helper functions which then use this function for the actual numerical parsing. This function recognizes both upper-case, lower-case, and mixed-case hexadecimal.
Convert a non-negative integer into a lower-case ASCII hexadecimal
string. Returns Nothing on negative inputs.
Convert a bitvector into a lower-case ASCII hexadecimal string. This is helpful for visualizing raw binary data, rather than for parsing as such.
Octal conversions
Read a non-negative integral value in ASCII octal format.
Returns Nothing if there is no integer at the beginning of the
string, otherwise returns Just the integer read and the remainder
of the string.
This function does not recognize the various octal sigils like "0o", but because there are different variants, those are best handled by helper functions which then use this function for the actual numerical parsing.
Convert a non-negative integer into an ASCII octal string.
Returns Nothing on negative inputs.