Replace — Sn

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 TryReplace(Text: str, Search: str, Replacement: str) -> Result<String, AllocationError>

Creates an owning UTF-8 string with ordinal nonoverlapping replacements. Text: Valid UTF-8 input, borrowed only for this operation. Search: Valid UTF-8 pattern; empty inserts at every scalar boundary. Replacement: Valid UTF-8 bytes copied for each admitted match. Return: Owning String, or recoverable AllocationError with no partial result. Note: Uses the ordinal Find search cost; never rescans inserted replacement bytes.

Example

module example.text_replacement;
from std.text import TryReplace;
// Transient owning strings stay inside the constant frame; only its scalar result escapes.
const fn VerifyConstantReplacement() -> i32 {
    switch TryReplace("λ/path/path", "path", "leaf") {
        case .Ok { Value = Changed } => {
            if Changed.View != "λ/leaf/leaf" { return 1; }
        }
        case .Err { Error = _ } => return 2;
    }
    switch TryReplace("λA", "", "-") {
        case .Ok { Value = Changed } => {
            if Changed.View != "-λ-A-" { return 3; }
        }
        case .Err { Error = _ } => return 4;
    }
    switch TryReplace("aaa", "aa", "X") {
        case .Ok { Value = Changed } => {
            if Changed.View != "Xa" { return 5; }
        }
        case .Err { Error = _ } => return 6;
    }
    return 0;
}
const ConstantStatus: i32 = VerifyConstantReplacement();
// Runtime parameters keep this dual-stage call on its ordinary runtime path.
fn VerifyRuntimeReplacement(Text: str, Search: str, Replacement: str, Expected: str) -> bool {
    switch TryReplace(Text, Search, Replacement) {
        case .Ok { Value = Changed } => return Changed.View == Expected;
        case .Err { Error = _ } => return false;
    }
}
fn Main() -> i32 {
    if ConstantStatus != 0 { return ConstantStatus; }
    if !VerifyRuntimeReplacement("λ/path/path", "path", "leaf", "λ/leaf/leaf") { return 7; }
    if !VerifyRuntimeReplacement("λA", "", "-", "-λ-A-") { return 8; }
    if !VerifyRuntimeReplacement("aaa", "aa", "X", "Xa") { return 9; }
    return 0;
}