Roadmap

This page describes what the language and tools can do in this tree, then points to recorded gaps and checked examples of unfinished design work. Use it to choose a task; read the standard for the rule and the implementation for its current limits.

Closed data with labelled fields is already available. This complete program prints its field:

(
	i/stdio
	i/core
)
main = () {
	record = (a = 1)
	stdio.print(core.inspect(record.a))
}

1

In this treeCopy Anchor Link

These groups describe available features, not full conformance to every rule in their chapters. The gap register records the exceptions.

The following command list comes from i --help on this tree. Each command has its own help:

i build --help lists these targets:

Editor sources provide VS Code highlighting and language-server integration, Zed integration, and the tree-sitter grammar. The server supplies diagnostics, hover, navigation, completion, and formatting.

Recorded gapsCopy Anchor Link

spec-known-gaps.md records task environment and scope handling; pattern parsing and usefulness warnings; effect rows and resource scope; Float text; type inference, applications, and polymorphic types; and macro budget accounting. It separately records a program that passes the checker and traps. The contributing page groups these tasks by their recorded identifiers.

Designed, not landedCopy Anchor Link

A note’s opening status can describe an older tree. The following claims concern specific parts of a design and have been checked against this tree:

• records.md proposes structural field inference and width subtyping beyond today’s closed data shapes. Its generic field-read idea, written in today’s syntax as get = (r) { r.a }, is rejected by the supplied compiler with E0506 because the value needs a known type. Passing (a = 1, b = 2) to a parameter annotated (a = Int) also fails with E0501, rather than forgetting the extra field. Reading the checker also finds Head::Shape, with none of the proposed Head::Record, Ty::Rec, or Ty::Without variants. The closed data example above already works; calling all records unimplemented would be wrong.
• std-v3.md redesigns the standard library. Two source comparisons show that std/src is still the pre-redesign library: json.i has parse returning Result(Json, JsonError) and a separate pretty, while the plan requires a raised JsonError and two print shapes; time.i has divide returning Result(Duration, TimeError) and lacks the planned high-level Clock type. These source checks establish the status of those changes, not every row of the plan.
• ast-hir-merge.md recommends keeping a syntax tree and HIR while removing the older syntax tree. The syntax entry point still calls lower::lower and returns the old ast::Module; the old tree and conversion remain. That removal has not landed.

Historical reports and plans whose present status is uncertain are omitted from this list. These notes make no promise of a delivery date.

See alsoCopy Anchor Link

• The standard: data
• How to send changes