std.ascii

immutable string fullHexDigits;

0 .. 9A .. Fa .. f

immutable string hexDigits;

0 .. 9A .. F

immutable string lowerHexDigits;

0 .. 9a .. f

immutable string digits;

0 .. 9

immutable string octalDigits;

0 .. 7

immutable string letters;

A .. Za .. z

immutable string uppercase;

A .. Z

immutable string lowercase;

a .. z

immutable string whitespace;

ASCII whitespace

enum LetterCase: bool;

Letter case specifier.

upper

Upper case letters

lower

Lower case letters

immutable string newline;

Newline sequence for this system.

pure nothrow @nogc @safe bool isAlphaNum(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is a letter or a number (0 .. 9, a .. z, A .. Z).

Examples:

assert( isAlphaNum('A'));
assert( isAlphaNum('1'));
assert(!isAlphaNum('#'));

// N.B.: does not return true for non-ASCII Unicode alphanumerics:
assert(!isAlphaNum('á'));

pure nothrow @nogc @safe bool isAlpha(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is an ASCII letter (A .. Z, a .. z).

Examples:

assert( isAlpha('A'));
assert(!isAlpha('1'));
assert(!isAlpha('#'));

// N.B.: does not return true for non-ASCII Unicode alphabetic characters:
assert(!isAlpha('á'));

pure nothrow @nogc @safe bool isLower(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is a lowercase ASCII letter (a .. z).

Examples:

assert( isLower('a'));
assert(!isLower('A'));
assert(!isLower('#'));

// N.B.: does not return true for non-ASCII Unicode lowercase letters
assert(!isLower('á'));
assert(!isLower('Á'));

pure nothrow @nogc @safe bool isUpper(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is an uppercase ASCII letter (A .. Z).

Examples:

assert( isUpper('A'));
assert(!isUpper('a'));
assert(!isUpper('#'));

// N.B.: does not return true for non-ASCII Unicode uppercase letters
assert(!isUpper('á'));
assert(!isUpper('Á'));

pure nothrow @nogc @safe bool isDigit(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is a digit (0 .. 9).

Examples:

assert( isDigit('3'));
assert( isDigit('8'));
assert(!isDigit('B'));
assert(!isDigit('#'));

// N.B.: does not return true for non-ASCII Unicode numbers
assert(!isDigit('０')); // full-width digit zero (U+FF10)
assert(!isDigit('４')); // full-width digit four (U+FF14)

pure nothrow @nogc @safe bool isOctalDigit(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is a digit in base 8 (0 .. 7).

Examples:

assert( isOctalDigit('0'));
assert( isOctalDigit('7'));
assert(!isOctalDigit('8'));
assert(!isOctalDigit('A'));
assert(!isOctalDigit('#'));

pure nothrow @nogc @safe bool isHexDigit(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is a digit in base 16 (0 .. 9, A .. F, a .. f).

Examples:

assert( isHexDigit('0'));
assert( isHexDigit('A'));
assert( isHexDigit('f')); // lowercase hex digits are accepted
assert(!isHexDigit('g'));
assert(!isHexDigit('G'));
assert(!isHexDigit('#'));

pure nothrow @nogc @safe bool isWhite(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether or not c is a whitespace character. That includes the space, tab, vertical tab, form feed, carriage return, and linefeed characters.

Examples:

assert( isWhite(' '));
assert( isWhite('\t'));
assert( isWhite('\n'));
assert(!isWhite('1'));
assert(!isWhite('a'));
assert(!isWhite('#'));

// N.B.: Does not return true for non-ASCII Unicode whitespace characters.
static import std.uni;
assert(std.uni.isWhite('\u00A0'));
assert(!isWhite('\u00A0')); // std.ascii.isWhite

pure nothrow @nogc @safe bool isControl(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether c is a control character.

Examples:

assert( isControl('\0'));
assert( isControl('\022'));
assert( isControl('\n')); // newline is both whitespace and control
assert(!isControl(' '));
assert(!isControl('1'));
assert(!isControl('a'));
assert(!isControl('#'));

// N.B.: non-ASCII Unicode control characters are not recognized:
assert(!isControl('\u0080'));
assert(!isControl('\u2028'));
assert(!isControl('\u2029'));

pure nothrow @nogc @safe bool isPunctuation(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether or not c is a punctuation character. That includes all ASCII characters which are not control characters, letters, digits, or whitespace.

Examples:

assert( isPunctuation('.'));
assert( isPunctuation(','));
assert( isPunctuation(':'));
assert( isPunctuation('!'));
assert( isPunctuation('#'));
assert( isPunctuation('~'));
assert( isPunctuation('+'));
assert( isPunctuation('_'));

assert(!isPunctuation('1'));
assert(!isPunctuation('a'));
assert(!isPunctuation(' '));
assert(!isPunctuation('\n'));
assert(!isPunctuation('\0'));

// N.B.: Non-ASCII Unicode punctuation characters are not recognized.
assert(!isPunctuation('\u2012')); // (U+2012 = en-dash)

pure nothrow @nogc @safe bool isGraphical(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether or not c is a printable character other than the space character.

Examples:

assert( isGraphical('1'));
assert( isGraphical('a'));
assert( isGraphical('#'));
assert(!isGraphical(' ')); // whitespace is not graphical
assert(!isGraphical('\n'));
assert(!isGraphical('\0'));

// N.B.: Unicode graphical characters are not regarded as such.
assert(!isGraphical('á'));

pure nothrow @nogc @safe bool isPrintable(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether or not c is a printable character - including the space character.

Examples:

assert( isPrintable(' '));  // whitespace is printable
assert( isPrintable('1'));
assert( isPrintable('a'));
assert( isPrintable('#'));
assert(!isPrintable('\0')); // control characters are not printable

// N.B.: Printable non-ASCII Unicode characters are not recognized.
assert(!isPrintable('á'));

pure nothrow @nogc @safe bool isASCII(dchar c);

Parameters:

dchar c

The character to test.

Returns:

Whether or not c is in the ASCII character set - i.e. in the range 0 .. 0x7F.

Examples:

assert( isASCII('a'));
assert(!isASCII('á'));

auto toLower(C)(C c)
if (is(C : dchar));

Converts an ASCII letter to lowercase.

Parameters:

C c	A character of any type that implicitly converts to dchar. In the case where it's a built-in type, or an enum of a built-in type, Unqual!(OriginalType!C) is returned, whereas if it's a user-defined type, dchar is returned.

Returns:

The corresponding lowercase letter, if c is an uppercase ASCII character, otherwise c itself.

Examples:

writeln(toLower('a')); // 'a'
writeln(toLower('A')); // 'a'
writeln(toLower('#')); // '#'

// N.B.: Non-ASCII Unicode uppercase letters are not converted.
writeln(toLower('Á')); // 'Á'

auto toUpper(C)(C c)
if (is(C : dchar));

Converts an ASCII letter to uppercase.

Parameters:

C c	Any type which implicitly converts to dchar. In the case where it's a built-in type, or an enum of a built-in type, Unqual!(OriginalType!C) is returned, whereas if it's a user-defined type, dchar is returned.

Returns:

The corresponding uppercase letter, if c is a lowercase ASCII character, otherwise c itself.

Examples:

writeln(toUpper('a')); // 'A'
writeln(toUpper('A')); // 'A'
writeln(toUpper('#')); // '#'

// N.B.: Non-ASCII Unicode lowercase letters are not converted.
writeln(toUpper('á')); // 'á'