String & Slice Proposal

[tahadostifam]

String and Slice Proposal

Overview

Cyrus provides two fundamental string representations:

Type	Description
char*	Pointer to a null-terminated string
char[]	Slice (ptr + len)

String literals may be created as either regular slices or null-terminated strings.

String Literals

Null-Terminated String

const name: char* = z"Hello, World";

The z prefix guarantees a trailing '\0'.

Memory layout:

H e l l o ,   W o r l d \0

Slice String

const name: char[] = "Hello, World";

Creates a slice whose length is known at compile time.

Memory layout:

ptr -> "Hello, World"
len -> 12

Slice from a Null-Terminated Literal

const name: char[] = z"Hello, World";

Creates a slice view over a null-terminated string.

The slice length excludes the trailing '\0'.

Creating Slices from Pointers

Pointers may be explicitly converted into slices using @slice.

var ptr: char* = get_buffer();

var text: char[] = @slice(ptr, 12);

Equivalent conceptual representation:

{
    ptr: ptr,
    len: 12,
}

The conversion is explicit because the compiler cannot infer the length of a raw pointer.

Accessing Slice Components

Slices expose their pointer and length directly.

var ptr: char* = text.ptr;
var len: usize = text.len;

No conversion builtin is required.

Converting a Slice to a Null-Terminated String

A slice may be explicitly converted to a null-terminated string pointer using @as_zstr.

var text: char[] = z"Hello";

var cstr: char* = @as_zstr(text);

Requirements

@as_zstr requires that the slice references a buffer whose element immediately following the slice is '\0'.

Valid:

var text: char[] = z"Hello";

var cstr: char* = @as_zstr(text);

Potentially invalid:

var text: char[] = "Hello";

var cstr: char* = @as_zstr(text);

The implementation may emit a compile-time error, runtime check, or require an unsafe context if null termination cannot be proven.

Summary

const cstr: char* = z"Hello";

const slice1: char[] = "Hello";

const slice2: char[] = z"Hello";

var ptr: char* = get_buffer();

var view: char[] = @slice(ptr, 64);

var raw: char* = view.ptr;

var zptr: char* = @as_zstr(slice2);

Builtins

@slice(ptr, len)   // pointer -> slice
@as_zstr(slice)    // slice -> null-terminated string pointer