Formatting

This library is in flux. APIs may change without notice. Generated from source on 3/14/2026.

Zero-overhead string formatting with Liquid-style templates.

fmt.kz

Koru Standard Library: String Formatting Zero-overhead string formatting with Liquid-style templates. Returns allocated strings with phantom obligation tracking. DESIGN: "Hidden but overridable" - fmt.blk: Uses page_allocator internally, user never thinks about it - fmt.blk.with_allocator: Explicit control when needed - Auto-discharge handles cleanup via phantom obligations

// ============================================================================
// FMT.DEALLOC - Discharge the [allocated!] obligation
// ============================================================================
~pub event fmt.dealloc {
    formatted: *FormattedText[!allocated]
}
| done

// ============================================================================
// FMT.BLK - Format with hidden default allocator (page_allocator)
// ============================================================================
// 
// Syntax:
//   fmt.blk {
//       Hello {{ name:s }}!
//       Count: {{ count:d }}
//   }
//   | formatted f |> ... use f.text ...
// 
// The FormattedText carries its allocator, so fmt.dealloc knows how to free.
// Auto-discharge inserts fmt.dealloc automatically.
~[comptime|transform]pub event fmt.blk {
    source: Source,
    invocation: *const Invocation,
    item: *const Item,
    program: *const Program,
    allocator: std.mem.Allocator
}
| formatted *FormattedText[allocated!]

~[norun]pub event fmt.blk.impl {
    text: []const u8,
}

// ============================================================================
// FMT.BLK.WITH_ALLOCATOR - Explicit allocator control
// ============================================================================
// 
// For when you need a specific allocator (arena, etc.)
// 
// Syntax:
//   fmt.blk.with_allocator(allocator: my_arena) {
//       Hello {{ name:s }}!
//   }
//   | formatted f |> ...
// 
// TODO: fmt.blk.with_allocator - requires solving how user params
// coexist with transform infrastructure params in the pass runner.
// ~[comptime|transform]pub event fmt.blk.with_allocator { ... }
// 
// ============================================================================
// FMT.LN - One-line format with Liquid templates, returns text via continuation
// ============================================================================
// 
// Syntax:
//   std.fmt:ln("Hello {{ name:s }}! Count: {{ count:d }}")
//   | line l |> ... use l.text ...
// 
// Zero allocation: uses a thread-local buffer (safe across workers).
// The {{ var:spec }} placeholders are resolved at compile time into
// std.fmt.bufPrint calls that run at runtime in the caller's scope.
~[comptime|transform]pub event ln {
    invocation: *const Invocation,
    item: *const Item,
    program: *const Program,
    allocator: std.mem.Allocator
}
| transformed { program: *const Program }

~[norun]pub event ln.impl {
    expr: []const u8,
}
| line { text: []const u8 }