std.string

concat function

pub fn concat(a: string, b: string): string

The two joined — what + on strings compiles to.

stdlib/std/string.lyr:15

fromInt function

pub fn fromInt(value: int): string

The decimal text of the value.

stdlib/std/string.lyr:18

fromUint function

pub fn fromUint(value: uint): string

The decimal text of an unsigned value.

stdlib/std/string.lyr:23

fromFloat function

pub fn fromFloat(value: float): string

The decimal text of the value.

stdlib/std/string.lyr:25

fromBool function

pub fn fromBool(value: bool): string

"true" or "false".

stdlib/std/string.lyr:27

fromChar function

pub fn fromChar(value: char): string

The character as a one-character string.

stdlib/std/string.lyr:29

repeat function

pub fn repeat(value: string, count: int): string

The string repeated count times — what s * n compiles to.

stdlib/std/string.lyr:34

fromChars function

pub fn fromChars(chars: char[]): string

The characters joined back into one string — the inverse of toChars. Native since v1.14: one call instead of one string per character.

stdlib/std/string.lyr:46

utf8Decode function

pub fn utf8Decode(bytes: uint8[]): ?string

The bytes as a string, STRICTLY: invalid UTF-8 answers null rather than a U+FFFD quietly standing in for the data — the difference to std.io.file.text, whose replacement decoding is documented there.

stdlib/std/string.lyr:56

Utf8Error class

pub class Utf8Error :: [Throwable]

Where a byte sequence stopped being UTF-8: the 0-based offset of the byte that broke it.

offset: int

pub fn message(): string

stdlib/std/string.lyr:59

utf8DecodeOrThrow function

pub fn utf8DecodeOrThrow(bytes: uint8[]): string throws Utf8Error

utf8Decode, with the reason when the bytes are not UTF-8: which byte broke the sequence.

stdlib/std/string.lyr:72

isDigit function

pub fn isDigit(c: char): bool

'0' through '9'.

stdlib/std/string.lyr:387

isAlpha function

pub fn isAlpha(c: char): bool

An ASCII letter.

stdlib/std/string.lyr:393

isAlphanumeric function

pub fn isAlphanumeric(c: char): bool

An ASCII letter or a digit.

stdlib/std/string.lyr:398

isWhitespace function

pub fn isWhitespace(c: char): bool

Space, tab, \n or \r.

stdlib/std/string.lyr:403

isUpper function

pub fn isUpper(c: char): bool

'A' through 'Z'.

stdlib/std/string.lyr:408

isLower function

pub fn isLower(c: char): bool

'a' through 'z'.

stdlib/std/string.lyr:413

charToDigit function

pub fn charToDigit(c: char): ?int

The numeric value of a digit, or null when it is not one.

?int rather than -1: a failure the caller has to handle belongs in the type.

stdlib/std/string.lyr:420

digitToChar function

pub fn digitToChar(value: int): ?char

The digit as a character, or null outside 0..9.

stdlib/std/string.lyr:428

join function

pub fn join(parts: string[], separator: string): string

Joins the parts with a separator: the inverse of split. One native call — a left fold would copy the whole result once per part.

stdlib/std/string.lyr:455

parseInt function

pub fn parseInt(value: string): ?int

"-42" becomes -42, anything else null.

No overflow protection: a number beyond int64 wraps rather than yielding null. Detecting it would need a division per digit.

stdlib/std/string.lyr:470

parseIntRadix function

pub fn parseIntRadix(value: string, radix: int): ?int

From a base of 2 to 36. Letters continue from a/A.

stdlib/std/string.lyr:504

parseBool function

pub fn parseBool(value: string): ?bool

Exactly "true" or "false"; anything else is null.

stdlib/std/string.lyr:549

parseFloat function

pub fn parseFloat(value: string): ?float

The closest float to the decimal the text spells — "3.5", "-0.25", ".5", "42", exponent notation included ("1e-6", "2.5E3") — or null when the text spells none. Strict about shape: no whitespace, no separators, and the words NaN and Infinity are not numbers. A magnitude beyond the type rounds to the infinities, as IEEE 754 prescribes.

Native because the conversion is CORRECTLY ROUNDED, which needs arbitrary-precision arithmetic in the worst cases; an approximate parser hands back a float the text did not say. parseFloat(fromFloat(x)) is x again, for every finite x.

stdlib/std/string.lyr:567

StringBuilder class

pub class StringBuilder

Builds a string piece by piece.

s = s + part in a loop is quadratic: every step copies the whole string so far. The builder collects the parts and joins them once.

The backing is a doubling string[], written by hand because this module must not import std.collections.

parts: string[]

count: int

pub static fn new(): StringBuilder

pub mut fn append(value: string): void

pub mut fn appendLine(value: string): void

pub mut fn appendChar(value: char): void

pub fn build(): string

stdlib/std/string.lyr:578