rust/src/libcore/char.rs

349 lines
10 KiB
Rust

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Utilities for manipulating the char type
use char;
use cmp::Eq;
use option::{None, Option, Some};
use str;
use u32;
use uint;
use unicode;
/*
Lu Uppercase_Letter an uppercase letter
Ll Lowercase_Letter a lowercase letter
Lt Titlecase_Letter a digraphic character, with first part uppercase
Lm Modifier_Letter a modifier letter
Lo Other_Letter other letters, including syllables and ideographs
Mn Nonspacing_Mark a nonspacing combining mark (zero advance width)
Mc Spacing_Mark a spacing combining mark (positive advance width)
Me Enclosing_Mark an enclosing combining mark
Nd Decimal_Number a decimal digit
Nl Letter_Number a letterlike numeric character
No Other_Number a numeric character of other type
Pc Connector_Punctuation a connecting punctuation mark, like a tie
Pd Dash_Punctuation a dash or hyphen punctuation mark
Ps Open_Punctuation an opening punctuation mark (of a pair)
Pe Close_Punctuation a closing punctuation mark (of a pair)
Pi Initial_Punctuation an initial quotation mark
Pf Final_Punctuation a final quotation mark
Po Other_Punctuation a punctuation mark of other type
Sm Math_Symbol a symbol of primarily mathematical use
Sc Currency_Symbol a currency sign
Sk Modifier_Symbol a non-letterlike modifier symbol
So Other_Symbol a symbol of other type
Zs Space_Separator a space character (of various non-zero widths)
Zl Line_Separator U+2028 LINE SEPARATOR only
Zp Paragraph_Separator U+2029 PARAGRAPH SEPARATOR only
Cc Control a C0 or C1 control code
Cf Format a format control character
Cs Surrogate a surrogate code point
Co Private_Use a private-use character
Cn Unassigned a reserved unassigned code point or a noncharacter
*/
pub use is_alphabetic = unicode::derived_property::Alphabetic;
pub use is_XID_start = unicode::derived_property::XID_Start;
pub use is_XID_continue = unicode::derived_property::XID_Continue;
/**
* Indicates whether a character is in lower case, defined
* in terms of the Unicode General Category 'Ll'
*/
#[inline(always)]
pub pure fn is_lowercase(c: char) -> bool {
return unicode::general_category::Ll(c);
}
/**
* Indicates whether a character is in upper case, defined
* in terms of the Unicode General Category 'Lu'.
*/
#[inline(always)]
pub pure fn is_uppercase(c: char) -> bool {
return unicode::general_category::Lu(c);
}
/**
* Indicates whether a character is whitespace. Whitespace is defined in
* terms of the Unicode General Categories 'Zs', 'Zl', 'Zp'
* additional 'Cc'-category control codes in the range [0x09, 0x0d]
*/
#[inline(always)]
pub pure fn is_whitespace(c: char) -> bool {
return ('\x09' <= c && c <= '\x0d')
|| unicode::general_category::Zs(c)
|| unicode::general_category::Zl(c)
|| unicode::general_category::Zp(c);
}
/**
* Indicates whether a character is alphanumeric. Alphanumericness is
* defined in terms of the Unicode General Categories 'Nd', 'Nl', 'No'
* and the Derived Core Property 'Alphabetic'.
*/
#[inline(always)]
pub pure fn is_alphanumeric(c: char) -> bool {
return unicode::derived_property::Alphabetic(c) ||
unicode::general_category::Nd(c) ||
unicode::general_category::Nl(c) ||
unicode::general_category::No(c);
}
/// Indicates whether the character is an ASCII character
#[inline(always)]
pub pure fn is_ascii(c: char) -> bool {
c - ('\x7F' & c) == '\x00'
}
/// Indicates whether the character is numeric (Nd, Nl, or No)
#[inline(always)]
pub pure fn is_digit(c: char) -> bool {
return unicode::general_category::Nd(c) ||
unicode::general_category::Nl(c) ||
unicode::general_category::No(c);
}
/**
* Checks if a character parses as a numeric digit in the given radix.
* Compared to `is_digit()`, this function only recognizes the ascii
* characters `0-9`, `a-z` and `A-Z`.
*
* Returns `true` if `c` is a valid digit under `radix`, and `false`
* otherwise.
*
* Fails if given a `radix` > 36.
*
* Note: This just wraps `to_digit()`.
*/
#[inline(always)]
pub pure fn is_digit_radix(c: char, radix: uint) -> bool {
match to_digit(c, radix) {
Some(_) => true,
None => false
}
}
/**
* Convert a char to the corresponding digit.
*
* # Return value
*
* If `c` is between '0' and '9', the corresponding value
* between 0 and 9. If `c` is 'a' or 'A', 10. If `c` is
* 'b' or 'B', 11, etc. Returns none if the char does not
* refer to a digit in the given radix.
*
* # Failure
* Fails if given a `radix` outside the range `[0..36]`.
*/
#[inline]
pub pure fn to_digit(c: char, radix: uint) -> Option<uint> {
if radix > 36 {
fail!(fmt!("to_digit: radix %? is to high (maximum 36)", radix));
}
let val = match c {
'0' .. '9' => c as uint - ('0' as uint),
'a' .. 'z' => c as uint + 10u - ('a' as uint),
'A' .. 'Z' => c as uint + 10u - ('A' as uint),
_ => return None
};
if val < radix { Some(val) }
else { None }
}
/**
* Converts a number to the ascii character representing it.
*
* Returns `Some(char)` if `num` represents one digit under `radix`,
* using one character of `0-9` or `a-z`, or `None` if it doesn't.
*
* Fails if given an `radix` > 36.
*/
#[inline]
pub pure fn from_digit(num: uint, radix: uint) -> Option<char> {
if radix > 36 {
fail!(fmt!("from_digit: radix %? is to high (maximum 36)", num));
}
if num < radix {
if num < 10 {
Some(('0' as uint + num) as char)
} else {
Some(('a' as uint + num - 10u) as char)
}
} else {
None
}
}
/**
* Return the hexadecimal unicode escape of a char.
*
* The rules are as follows:
*
* - chars in [0,0xff] get 2-digit escapes: `\\xNN`
* - chars in [0x100,0xffff] get 4-digit escapes: `\\uNNNN`
* - chars above 0x10000 get 8-digit escapes: `\\UNNNNNNNN`
*/
pub pure fn escape_unicode(c: char) -> ~str {
let s = u32::to_str_radix(c as u32, 16u);
let (c, pad) = (if c <= '\xff' { ('x', 2u) }
else if c <= '\uffff' { ('u', 4u) }
else { ('U', 8u) });
assert str::len(s) <= pad;
let mut out = ~"\\";
unsafe {
str::push_str(&mut out, str::from_char(c));
for uint::range(str::len(s), pad) |_i|
{ str::push_str(&mut out, ~"0"); }
str::push_str(&mut out, s);
}
out
}
/**
* Return a 'default' ASCII and C++11-like char-literal escape of a char.
*
* The default is chosen with a bias toward producing literals that are
* legal in a variety of languages, including C++11 and similar C-family
* languages. The exact rules are:
*
* - Tab, CR and LF are escaped as '\t', '\r' and '\n' respectively.
* - Single-quote, double-quote and backslash chars are backslash-escaped.
* - Any other chars in the range [0x20,0x7e] are not escaped.
* - Any other chars are given hex unicode escapes; see `escape_unicode`.
*/
pub pure fn escape_default(c: char) -> ~str {
match c {
'\t' => ~"\\t",
'\r' => ~"\\r",
'\n' => ~"\\n",
'\\' => ~"\\\\",
'\'' => ~"\\'",
'"' => ~"\\\"",
'\x20' .. '\x7e' => str::from_char(c),
_ => escape_unicode(c)
}
}
/**
* Compare two chars
*
* # Return value
*
* -1 if a < b, 0 if a == b, +1 if a > b
*/
#[inline(always)]
pub pure fn cmp(a: char, b: char) -> int {
return if b > a { -1 }
else if b < a { 1 }
else { 0 }
}
#[cfg(notest)]
impl Eq for char {
pure fn eq(&self, other: &char) -> bool { (*self) == (*other) }
pure fn ne(&self, other: &char) -> bool { (*self) != (*other) }
}
#[test]
fn test_is_lowercase() {
assert is_lowercase('a');
assert is_lowercase('ö');
assert is_lowercase('ß');
assert !is_lowercase('Ü');
assert !is_lowercase('P');
}
#[test]
fn test_is_uppercase() {
assert !is_uppercase('h');
assert !is_uppercase('ä');
assert !is_uppercase('ß');
assert is_uppercase('Ö');
assert is_uppercase('T');
}
#[test]
fn test_is_whitespace() {
assert is_whitespace(' ');
assert is_whitespace('\u2007');
assert is_whitespace('\t');
assert is_whitespace('\n');
assert !is_whitespace('a');
assert !is_whitespace('_');
assert !is_whitespace('\u0000');
}
#[test]
fn test_to_digit() {
assert to_digit('0', 10u) == Some(0u);
assert to_digit('1', 2u) == Some(1u);
assert to_digit('2', 3u) == Some(2u);
assert to_digit('9', 10u) == Some(9u);
assert to_digit('a', 16u) == Some(10u);
assert to_digit('A', 16u) == Some(10u);
assert to_digit('b', 16u) == Some(11u);
assert to_digit('B', 16u) == Some(11u);
assert to_digit('z', 36u) == Some(35u);
assert to_digit('Z', 36u) == Some(35u);
assert to_digit(' ', 10u).is_none();
assert to_digit('$', 36u).is_none();
}
#[test]
fn test_is_ascii() {
assert str::all(~"banana", char::is_ascii);
assert ! str::all(~"ประเทศไทย中华Việt Nam", char::is_ascii);
}
#[test]
fn test_is_digit() {
assert is_digit('2');
assert is_digit('7');
assert ! is_digit('c');
assert ! is_digit('i');
assert ! is_digit('z');
assert ! is_digit('Q');
}
#[test]
fn test_escape_default() {
assert escape_default('\n') == ~"\\n";
assert escape_default('\r') == ~"\\r";
assert escape_default('\'') == ~"\\'";
assert escape_default('"') == ~"\\\"";
assert escape_default(' ') == ~" ";
assert escape_default('a') == ~"a";
assert escape_default('~') == ~"~";
assert escape_default('\x00') == ~"\\x00";
assert escape_default('\x1f') == ~"\\x1f";
assert escape_default('\x7f') == ~"\\x7f";
assert escape_default('\xff') == ~"\\xff";
assert escape_default('\u011b') == ~"\\u011b";
assert escape_default('\U0001d4b6') == ~"\\U0001d4b6";
}
#[test]
fn test_escape_unicode() {
assert escape_unicode('\x00') == ~"\\x00";
assert escape_unicode('\n') == ~"\\x0a";
assert escape_unicode(' ') == ~"\\x20";
assert escape_unicode('a') == ~"\\x61";
assert escape_unicode('\u011b') == ~"\\u011b";
assert escape_unicode('\U0001d4b6') == ~"\\U0001d4b6";
}