Char

Standard library for character operations.

Functions in this module operate on type Char, a character that is represented by a single unicode codepoint. A codepoint is a numerical value that maps to a character, as per the unicode standard. Literal characters can be created with single quotes, such as in 'a' or '7', and escape sequences are supported, as in '\n' and '\t'.

To import all names from this module, use:

import Char (*)

With no import, you can still access anything with the prefix Char., like Char.to_lower.

Index

Name	Type	Description
`to_lower(ch)`	Char -> Char	Returns the lowercase form of `ch`.
`to_upper(ch)`	Char -> Char	Returns the uppercase form of `ch`.
`lower?(ch)`	Char -> Bool	Returns true if `ch` is a lowercase letter.
`upper?(ch)`	Char -> Bool	Returns true if `ch` is an uppercase letter.
`letter?(ch)`	Char -> Bool	Returns true if `ch` is a letter (unicode category `L`).
`digit?(ch)`	Char -> Bool	Returns true if `ch` is a digit (unicode category `Nd`).
`whitespace?(ch)`	Char -> Bool	Returns true if `ch` is whitespace ([unicode property `WSpace=yes`](https://en.
`to_int(a)`	Char -> Int	Converts `a` to an integer.
`to_atom(a)`	Char -> Atom	Converts `a` to an atom.

Functions

to_lower : Char -> Char
to_lower(ch)

Returns the lowercase form of ch. If ch isn't a letter, returns ch.

assert to_lower('a') == 'a'
assert to_lower('B') == 'b'
assert to_lower('.') == '.'

to_upper : Char -> Char
to_upper(ch)

Returns the uppercase form of ch. If ch isn't a letter, returns ch.

assert to_upper('a') == 'A'
assert to_upper('B') == 'B'
assert to_upper('3') == '3'

lower? : Char -> Bool
lower?(ch)

Returns true if ch is a lowercase letter.

assert lower?('a')
assert !lower?('B')
assert !lower?(',')

upper? : Char -> Bool
upper?(ch)

Returns true if ch is an uppercase letter.

assert !upper?('a')
assert upper?('B')
assert !upper?('[')

letter? : Char -> Bool
letter?(ch)

Returns true if ch is a letter (unicode category L).

assert letter?('m')
assert letter?('X')
assert !letter?('7')
assert !letter?(')')

digit? : Char -> Bool
digit?(ch)

Returns true if ch is a digit (unicode category Nd).

assert digit?('5')
assert digit?('0')
assert !digit?('b')
assert !digit?('"')

whitespace? : Char -> Bool
whitespace?(ch)

Returns true if ch is whitespace (unicode property WSpace=yes).

assert whitespace?('\t')
assert whitespace?('\n')
assert !whitespace?('s')
assert !whitespace?('9')

Implementations

impl ToInt for Char

The following functions are from the ToInt interface.

to_int : Char -> Int
to_int(a)

Converts a to an integer. See the full description in the ToInt interface.

impl ToAtom for Char

The following functions are from the ToAtom interface.

to_atom : Char -> Atom
to_atom(a)

Converts a to an atom. See the full description in the ToAtom interface.