287 lines
8.8 KiB
Rust
287 lines
8.8 KiB
Rust
//! Utilities for manipulating the char type
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// NB: transitionary, de-mode-ing.
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#[forbid(deprecated_mode)];
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#[forbid(deprecated_pattern)];
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use cmp::Eq;
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/*
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Lu Uppercase_Letter an uppercase letter
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Ll Lowercase_Letter a lowercase letter
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Lt Titlecase_Letter a digraphic character, with first part uppercase
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Lm Modifier_Letter a modifier letter
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Lo Other_Letter other letters, including syllables and ideographs
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Mn Nonspacing_Mark a nonspacing combining mark (zero advance width)
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Mc Spacing_Mark a spacing combining mark (positive advance width)
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Me Enclosing_Mark an enclosing combining mark
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Nd Decimal_Number a decimal digit
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Nl Letter_Number a letterlike numeric character
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No Other_Number a numeric character of other type
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Pc Connector_Punctuation a connecting punctuation mark, like a tie
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Pd Dash_Punctuation a dash or hyphen punctuation mark
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Ps Open_Punctuation an opening punctuation mark (of a pair)
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Pe Close_Punctuation a closing punctuation mark (of a pair)
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Pi Initial_Punctuation an initial quotation mark
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Pf Final_Punctuation a final quotation mark
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Po Other_Punctuation a punctuation mark of other type
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Sm Math_Symbol a symbol of primarily mathematical use
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Sc Currency_Symbol a currency sign
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Sk Modifier_Symbol a non-letterlike modifier symbol
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So Other_Symbol a symbol of other type
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Zs Space_Separator a space character (of various non-zero widths)
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Zl Line_Separator U+2028 LINE SEPARATOR only
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Zp Paragraph_Separator U+2029 PARAGRAPH SEPARATOR only
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Cc Control a C0 or C1 control code
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Cf Format a format control character
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Cs Surrogate a surrogate code point
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Co Private_Use a private-use character
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Cn Unassigned a reserved unassigned code point or a noncharacter
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*/
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export is_alphabetic,
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is_XID_start, is_XID_continue,
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is_lowercase, is_uppercase,
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is_whitespace, is_alphanumeric,
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is_ascii, is_digit,
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to_digit, cmp,
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escape_default, escape_unicode;
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use is_alphabetic = unicode::derived_property::Alphabetic;
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use is_XID_start = unicode::derived_property::XID_Start;
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use is_XID_continue = unicode::derived_property::XID_Continue;
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/**
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* Indicates whether a character is in lower case, defined
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* in terms of the Unicode General Category 'Ll'
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*/
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pure fn is_lowercase(c: char) -> bool {
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return unicode::general_category::Ll(c);
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}
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/**
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* Indicates whether a character is in upper case, defined
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* in terms of the Unicode General Category 'Lu'.
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*/
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pure fn is_uppercase(c: char) -> bool {
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return unicode::general_category::Lu(c);
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}
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/**
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* Indicates whether a character is whitespace, defined in
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* terms of the Unicode General Categories 'Zs', 'Zl', 'Zp'
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* additional 'Cc'-category control codes in the range [0x09, 0x0d]
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*/
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pure fn is_whitespace(c: char) -> bool {
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return ('\x09' <= c && c <= '\x0d')
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|| unicode::general_category::Zs(c)
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|| unicode::general_category::Zl(c)
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|| unicode::general_category::Zp(c);
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}
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/**
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* Indicates whether a character is alphanumeric, defined
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* in terms of the Unicode General Categories 'Nd',
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* 'Nl', 'No' and the Derived Core Property 'Alphabetic'.
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*/
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pure fn is_alphanumeric(c: char) -> bool {
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return unicode::derived_property::Alphabetic(c) ||
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unicode::general_category::Nd(c) ||
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unicode::general_category::Nl(c) ||
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unicode::general_category::No(c);
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}
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/// Indicates whether the character is an ASCII character
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pure fn is_ascii(c: char) -> bool {
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c - ('\x7F' & c) == '\x00'
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}
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/// Indicates whether the character is numeric (Nd, Nl, or No)
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pure fn is_digit(c: char) -> bool {
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return unicode::general_category::Nd(c) ||
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unicode::general_category::Nl(c) ||
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unicode::general_category::No(c);
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}
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/**
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* Convert a char to the corresponding digit.
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*
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* # Safety note
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*
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* This function returns none if `c` is not a valid char
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*
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* # Return value
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*
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* If `c` is between '0' and '9', the corresponding value
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* between 0 and 9. If `c` is 'a' or 'A', 10. If `c` is
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* 'b' or 'B', 11, etc. Returns none if the char does not
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* refer to a digit in the given radix.
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*/
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pure fn to_digit(c: char, radix: uint) -> Option<uint> {
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let val = match c {
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'0' .. '9' => c as uint - ('0' as uint),
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'a' .. 'z' => c as uint + 10u - ('a' as uint),
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'A' .. 'Z' => c as uint + 10u - ('A' as uint),
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_ => return None
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};
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if val < radix { Some(val) }
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else { None }
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}
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/**
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* Return the hexadecimal unicode escape of a char.
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*
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* The rules are as follows:
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*
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* - chars in [0,0xff] get 2-digit escapes: `\\xNN`
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* - chars in [0x100,0xffff] get 4-digit escapes: `\\uNNNN`
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* - chars above 0x10000 get 8-digit escapes: `\\UNNNNNNNN`
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*/
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fn escape_unicode(c: char) -> ~str {
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let s = u32::to_str(c as u32, 16u);
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let (c, pad) = (if c <= '\xff' { ('x', 2u) }
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else if c <= '\uffff' { ('u', 4u) }
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else { ('U', 8u) });
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assert str::len(s) <= pad;
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let mut out = ~"\\";
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str::push_str(out, str::from_char(c));
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for uint::range(str::len(s), pad) |_i| { str::push_str(out, ~"0"); }
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str::push_str(out, s);
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move out
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}
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/**
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* Return a 'default' ASCII and C++11-like char-literal escape of a char.
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*
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* The default is chosen with a bias toward producing literals that are
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* legal in a variety of languages, including C++11 and similar C-family
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* languages. The exact rules are:
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*
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* - Tab, CR and LF are escaped as '\t', '\r' and '\n' respectively.
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* - Single-quote, double-quote and backslash chars are backslash-escaped.
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* - Any other chars in the range [0x20,0x7e] are not escaped.
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* - Any other chars are given hex unicode escapes; see `escape_unicode`.
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*/
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fn escape_default(c: char) -> ~str {
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match c {
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'\t' => ~"\\t",
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'\r' => ~"\\r",
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'\n' => ~"\\n",
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'\\' => ~"\\\\",
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'\'' => ~"\\'",
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'"' => ~"\\\"",
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'\x20' .. '\x7e' => str::from_char(c),
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_ => escape_unicode(c)
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}
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}
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/**
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* Compare two chars
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*
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* # Return value
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*
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* -1 if a < b, 0 if a == b, +1 if a > b
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*/
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pure fn cmp(a: char, b: char) -> int {
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return if b > a { -1 }
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else if b < a { 1 }
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else { 0 }
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}
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impl char: Eq {
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pure fn eq(&&other: char) -> bool { self == other }
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pure fn ne(&&other: char) -> bool { self != other }
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}
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#[test]
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fn test_is_lowercase() {
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assert is_lowercase('a');
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assert is_lowercase('ö');
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assert is_lowercase('ß');
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assert !is_lowercase('Ü');
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assert !is_lowercase('P');
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}
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#[test]
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fn test_is_uppercase() {
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assert !is_uppercase('h');
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assert !is_uppercase('ä');
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assert !is_uppercase('ß');
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assert is_uppercase('Ö');
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assert is_uppercase('T');
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}
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#[test]
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fn test_is_whitespace() {
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assert is_whitespace(' ');
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assert is_whitespace('\u2007');
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assert is_whitespace('\t');
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assert is_whitespace('\n');
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assert !is_whitespace('a');
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assert !is_whitespace('_');
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assert !is_whitespace('\u0000');
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}
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#[test]
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fn test_to_digit() {
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assert to_digit('0', 10u) == Some(0u);
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assert to_digit('1', 2u) == Some(1u);
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assert to_digit('2', 3u) == Some(2u);
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assert to_digit('9', 10u) == Some(9u);
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assert to_digit('a', 16u) == Some(10u);
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assert to_digit('A', 16u) == Some(10u);
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assert to_digit('b', 16u) == Some(11u);
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assert to_digit('B', 16u) == Some(11u);
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assert to_digit('z', 36u) == Some(35u);
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assert to_digit('Z', 36u) == Some(35u);
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assert to_digit(' ', 10u).is_none();
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assert to_digit('$', 36u).is_none();
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}
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#[test]
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fn test_is_ascii() {
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assert str::all(~"banana", char::is_ascii);
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assert ! str::all(~"ประเทศไทย中华Việt Nam", char::is_ascii);
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}
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#[test]
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fn test_is_digit() {
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assert is_digit('2');
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assert is_digit('7');
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assert ! is_digit('c');
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assert ! is_digit('i');
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assert ! is_digit('z');
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assert ! is_digit('Q');
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}
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#[test]
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fn test_escape_default() {
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assert escape_default('\n') == ~"\\n";
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assert escape_default('\r') == ~"\\r";
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assert escape_default('\'') == ~"\\'";
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assert escape_default('"') == ~"\\\"";
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assert escape_default(' ') == ~" ";
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assert escape_default('a') == ~"a";
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assert escape_default('~') == ~"~";
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assert escape_default('\x00') == ~"\\x00";
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assert escape_default('\x1f') == ~"\\x1f";
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assert escape_default('\x7f') == ~"\\x7f";
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assert escape_default('\xff') == ~"\\xff";
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assert escape_default('\u011b') == ~"\\u011b";
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assert escape_default('\U0001d4b6') == ~"\\U0001d4b6";
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}
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#[test]
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fn test_escape_unicode() {
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assert escape_unicode('\x00') == ~"\\x00";
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assert escape_unicode('\n') == ~"\\x0a";
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assert escape_unicode(' ') == ~"\\x20";
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assert escape_unicode('a') == ~"\\x61";
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assert escape_unicode('\u011b') == ~"\\u011b";
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assert escape_unicode('\U0001d4b6') == ~"\\U0001d4b6";
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}
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