func main(): i32 { let value = load_value() catch failure { fallback_for(failure.message()) } if value == 42 { return 0 } return 1 } func load_value(): i32! { return error.new("example.unavailable", "the primary value is unavailable") } func fallback_for(message: &str): i32 { return 42 }

use std/fmt.Format use std/io struct Point { x: i32 y: i32 } instance Point { impl Format method &self.try_format_into(output: &+String): void! { output.try_push_str("(")? self.x.try_format_into(output)? output.try_push_str(", ")? self.y.try_format_into(output)? output.try_push_str(")")? return } } func main(): i32! { let point = Point { x: 3, y: 4 } let message = "point = ${point}\n" io.print(&message)? return 0 }

use std/io use std/vec.Vec struct Point { x: i32 y: i32 } instance Point { operator (&self == other: &Self): bool { return self.x == other.x && self.y == other.y } } func main(): i32! { let first = Point { x: 3, y: 4 } let same = Point { x: 3, y: 4 } let other = Point { x: 5, y: 6 } if first != same || first == other { return 1 } let points = Vec [move first, move other] if points[0] != same { return 1 } var values = Vec [1, 2, 3] values[1] = 4 if values[0] + values[1] + values[2] != 8 { return 1 } io.print("equality found the point\n")? return 0 }

struct Buffer { values: [i32; 3] } instance Buffer { operator (&self[index: usize]): &i32 { return &self.values[index] } operator (&+self[index: usize]): &+i32 { return &+self.values[index] } } func at<C>(container: &C, index: usize): i32 where (&C[usize]): &i32 { return container[index] } func main(): i32 { var buffer = Buffer { values: [3, 4, 5] } buffer[1] = 9 if at(&buffer, 1) != 9 { return 1 } return 0 }

nocter-arm64

Responsibility

Select, allocate, and encode ARM64 instructions for one immutable machine program.

Contract

The crate consumes target-independent machine operations and runtime roles. It publishes an Arm64Program containing encoded code/data sections and fixup information for the image writer. It does not inspect MIR semantics, declaration identities, source, or package state.

Internal Responsibilities

instruction and addressing selection
call, aggregate, pack, primitive, error, and region lowering
frame layout and register allocation
parallel-copy resolution
branch, code-to-data, and data-to-data fixups and instruction encoding

Invariants

ARM64 selection implements the ABI already classified by Machine.
The operation and selected-instruction enums are each classified exactly once. Subsystem helpers receive destructured payloads or a closed subsystem operation, never the complete parent enum.
Physical register decisions cannot change semantic value transport.
Every primitive expansion is selected by closed runtime role.
Data-pointer fixups identify exact eight-byte fields and section-local targets; executable image policy remains outside this crate.
A monotonic-counter observation is emitted as an ordered observation, never as a speculative bare system-register read.
Encoding is deterministic for one machine program.