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Module std.text

import std.text;

Public declaration contracts and authored examples. A page can document several related symbols. Implementation bodies are excluded.

fn

pub const fn StartsWith(Text: str, Prefix: str) -> bool

Compares a borrowed prefix using ordinal UTF-8 bytes. Text: Valid UTF-8 view borrowed only for this call. Prefix: Valid UTF-8 prefix; an empty prefix always matches. Return: True when Text begins with every byte of Prefix, without allocation.

Example

module example.borrowed_text_search;
from std.text import StartsWith, EndsWith, Find;
fn Main() -> i32 {
    let Text: str = "λ/path/λ";
    if !StartsWith(Text, "λ/") || !EndsWith(Text, "/λ") {
        return 1;
    }
    switch Find(Text, "path") {
        case .Some { Value = Offset } => {
            if Offset != 3_usize { return 2; }
        }
        case .None => return 3;
    }
    if Find(Text, "missing") is .Some { Value = _ } { return 4; }
    switch Find(Text, "") {
        case .Some { Value = Offset } => {
            if Offset != 0_usize { return 5; }
        }
        case .None => return 6;
    }
    if !StartsWith("", "") || !EndsWith(Text, "") { return 7; }
    return 0;
}

fn

pub const fn EndsWith(Text: str, Suffix: str) -> bool

Compares a borrowed suffix using ordinal UTF-8 bytes. Text: Valid UTF-8 view borrowed only for this call. Suffix: Valid UTF-8 suffix; an empty suffix always matches. Return: True when Text ends with every byte of Suffix, without allocation.

fn

pub const fn Find(Text: str, Pattern: str) -> usize?

Finds the first exact UTF-8 pattern and returns its borrowed-view byte offset. Text: Valid UTF-8 view borrowed only for this call. Pattern: Valid UTF-8 pattern; empty matches at offset zero. Return: First matching byte offset, or none when no match exists. @details No allocation, retained borrow or locale transformation is introduced. Worst-case work is O(Text.ByteLength * Pattern.ByteLength).