base-4.3.1.0: Basic libraries

Portabilityportable
Stabilityprovisional
Maintainer[email protected]

Numeric

Contents

Description

Odds and ends, mostly functions for reading and showing RealFloat-like kind of values.

Synopsis

Showing

showSignedSource

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.

showInt :: Integral a => a -> ShowSSource

Show non-negative Integral numbers in base 10.

showHex :: Integral a => a -> ShowSSource

Show non-negative Integral numbers in base 16.

showOct :: Integral a => a -> ShowSSource

Show non-negative Integral numbers in base 8.

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 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 -> ShowSSource

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 -> 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 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.

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

  1. n >= 1
  2. x = 0.d1d2...dn * (base**e)
  3. 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.

readIntSource

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 Int

-> ReadS a 

Reads an unsigned Integral value in an arbitrary base.

readDec :: Num a => ReadS aSource

Read an unsigned number in decimal notation.

readOct :: Num a => ReadS aSource

Read an unsigned number in octal notation.

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.

lexDigits :: ReadS StringSource

Reads a non-empty string of decimal digits.

Miscellaneous

fromRat :: RealFloat a => Rational -> aSource

Converts a Rational value into any type in class RealFloat.