| Portability | portable |
|---|---|
| Stability | provisional |
| Maintainer | libraries@haskell.org |
Numeric
Contents
Description
Odds and ends, mostly functions for reading and showing
RealFloat-like kind of values.
- showSigned :: Real a => (a -> ShowS) -> Int -> a -> ShowS
- showIntAtBase :: Integral a => a -> (Int -> Char) -> a -> ShowS
- showInt :: Integral a => a -> ShowS
- showHex :: Integral a => a -> ShowS
- showOct :: Integral a => a -> ShowS
- showEFloat :: RealFloat a => Maybe Int -> a -> ShowS
- showFFloat :: RealFloat a => Maybe Int -> a -> ShowS
- showGFloat :: RealFloat a => Maybe Int -> a -> ShowS
- showFloat :: RealFloat a => a -> ShowS
- floatToDigits :: RealFloat a => Integer -> a -> ([Int], Int)
- readSigned :: Real a => ReadS a -> ReadS a
- readInt :: Num a => a -> (Char -> Bool) -> (Char -> Int) -> ReadS a
- readDec :: Num a => ReadS a
- readOct :: Num a => ReadS a
- readHex :: Num a => ReadS a
- readFloat :: RealFrac a => ReadS a
- lexDigits :: ReadS String
- fromRat :: RealFloat a => Rational -> a
Showing
Arguments
| :: Real a | |
| => (a -> ShowS) | a function that can show unsigned values |
| -> Int | the precedence of the enclosing context |
| -> a | the value to show |
| -> ShowS |
Converts a possibly-negative Real value to a string.
showIntAtBase :: Integral a => a -> (Int -> Char) -> a -> ShowSSource
Shows a non-negative Integral number using the base specified by the
first argument, and the character representation specified by the second.
showEFloat :: RealFloat a => Maybe Int -> a -> ShowSSource
Show a signed RealFloat value
using scientific (exponential) notation (e.g. 2.45e2, 1.5e-3).
In the call showEFloat digs valdigs is Nothing,
the value is shown to full precision; if digs is Just dd digits after the decimal point are shown.
showFFloat :: RealFloat a => Maybe Int -> a -> ShowSSource
Show a signed RealFloat value
using standard decimal notation (e.g. 245000, 0.0015).
In the call showFFloat digs valdigs is Nothing,
the value is shown to full precision; if digs is Just dd digits after the decimal point are shown.
showGFloat :: RealFloat a => Maybe Int -> a -> ShowSSource
Show a signed RealFloat value
using standard decimal notation for arguments whose absolute value lies
between 0.1 and 9,999,999, and scientific notation otherwise.
In the call showGFloat digs valdigs is Nothing,
the value is shown to full precision; if digs is Just dd digits after the decimal point are shown.
showFloat :: RealFloat a => a -> ShowSSource
Show a signed RealFloat value to full precision
using standard decimal notation for arguments whose absolute value lies
between 0.1 and 9,999,999, and scientific notation otherwise.
floatToDigits :: RealFloat a => Integer -> a -> ([Int], Int)Source
floatToDigits takes a base and a non-negative RealFloat number,
and returns a list of digits and an exponent.
In particular, if x>=0, and
floatToDigits base x = ([d1,d2,...,dn], e)
then
n >= 1
x = 0.d1d2...dn * (base**e)
0 <= di <= base-1
Reading
NB: readInt is the 'dual' of showIntAtBase,
and readDec is the `dual' of showInt.
The inconsistent naming is a historical accident.
readSigned :: Real a => ReadS a -> ReadS aSource
Reads a signed Real value, given a reader for an unsigned value.
Arguments
| :: Num a | |
| => a | the base |
| -> (Char -> Bool) | a predicate distinguishing valid digits in this base |
| -> (Char -> Int) | a function converting a valid digit character to an |
| -> ReadS a |
Reads an unsigned Integral value in an arbitrary base.
readHex :: Num a => ReadS aSource
Read an unsigned number in hexadecimal notation. Both upper or lower case letters are allowed.
readFloat :: RealFrac a => ReadS aSource
Reads an unsigned RealFrac value,
expressed in decimal scientific notation.