Numeric
Copyright | (c) The University of Glasgow 2002 |
---|---|
License | BSD-style (see the file libraries/base/LICENSE) |
Maintainer | [email protected] |
Stability | provisional |
Portability | portable |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
Contents
Description
Odds and ends, mostly functions for reading and showing RealFloat
-like kind of values.
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, Show a) => a -> (Int -> Char) -> a -> ShowS Source
Shows a non-negative Integral
number using the base specified by the first argument, and the character representation specified by the second.
showInt :: Integral a => a -> ShowS Source
Show non-negative Integral
numbers in base 10.
showHex :: (Integral a, Show a) => a -> ShowS Source
Show non-negative Integral
numbers in base 16.
showOct :: (Integral a, Show a) => a -> ShowS Source
Show non-negative Integral
numbers in base 8.
showEFloat :: RealFloat a => Maybe Int -> a -> ShowS Source
Show a signed RealFloat
value using scientific (exponential) notation (e.g. 2.45e2
, 1.5e-3
).
In the call showEFloat digs val
, if digs
is Nothing
, the value is shown to full precision; if digs
is Just d
, then at most d
digits after the decimal point are shown.
showFFloat :: RealFloat a => Maybe Int -> a -> ShowS Source
Show a signed RealFloat
value using standard decimal notation (e.g. 245000
, 0.0015
).
In the call showFFloat digs val
, if digs
is Nothing
, the value is shown to full precision; if digs
is Just d
, then at most d
digits after the decimal point are shown.
showGFloat :: RealFloat a => Maybe Int -> a -> ShowS Source
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 val
, if digs
is Nothing
, the value is shown to full precision; if digs
is Just d
, then at most d
digits after the decimal point are shown.
showFFloatAlt :: RealFloat a => Maybe Int -> a -> ShowS Source
Show a signed RealFloat
value using standard decimal notation (e.g. 245000
, 0.0015
).
This behaves as showFFloat
, except that a decimal point is always guaranteed, even if not needed.
Since: 4.7.0.0
showGFloatAlt :: RealFloat a => Maybe Int -> a -> ShowS Source
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.
This behaves as showFFloat
, except that a decimal point is always guaranteed, even if not needed.
Since: 4.7.0.0
showFloat :: RealFloat a => a -> ShowS Source
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 a Source
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.
readDec :: (Eq a, Num a) => ReadS a Source
Read an unsigned number in decimal notation.
readOct :: (Eq a, Num a) => ReadS a Source
Read an unsigned number in octal notation.
readHex :: (Eq a, Num a) => ReadS a Source
Read an unsigned number in hexadecimal notation. Both upper or lower case letters are allowed.
readFloat :: RealFrac a => ReadS a Source
Reads an unsigned RealFrac
value, expressed in decimal scientific notation.
lexDigits :: ReadS String Source
Reads a non-empty string of decimal digits.
Miscellaneous
© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/7.10.3/docs/html/libraries/base-4.8.2.0/Numeric.html