Language Spec (v1.0.0)

The current spec is a release-candidate document with Last Updated: 2026-01-29.

This page is a navigational guide: it tells you what’s in the spec and what to cross-check against the implementation.

The Source of Truth

Lexical structure: keywords, tokens, identifiers, literals
Types: primitives, generics, structs/enums/traits, Knowledge<T> (epistemic types)
Expressions & statements: precedence, control flow
Declarations: modules/imports/visibility, type aliases, effect declarations
Effect system: with ..., operations, handlers (model-level)
Ownership/borrowing: linear/affine intent and rules
Units of measure: dimension model, unit definitions, conversions
Refinement types: { x: T | predicate } syntax and checking model
GPU programming: kernel surface syntax and execution model
Standard library: expected modules and responsibilities

Use the spec to understand the intended model (especially around effects, ownership, epistemics, and units).
For “what compiles today”, validate against:
- a runnable tests/run-pass/ fixture, or
- souc check your_file.sio in your current build configuration.