The Codex of Changes

A pointer to the version history rather than a full retelling. The authoritative changelog is CHANGELOG.md; this chapter highlights only the shifts that affect a rune you’ve already written.

What’s currently alive

The shape every other chapter documents — the DsRune trait with its seven methods, the six DsNode variants, the three on forms (Form B, Form C, callback-form), enchants, niches, match arms, the name: Option<syn::Ident> attr shape — is the shape that ships today on crates.io. Code written against the current docs compiles against the current crates.

Migration notes by surface

If you have an existing rune from an earlier release, here’s what’s changed underneath you. Each entry assumes you’re on the previous shape and need to move to the current one.

on EventKind handlers

Earlier the parser had a top-level DsOn node that sat next to widget / if / iter / niche / match in DsTree. The trait had a matching inscribe_on method.

The current shape has neither. on clauses fold into the widget they attach to, reaching the rune as on_handlers: &[DsOn] on inscribe_widget. There is no DsNode::On variant and no inscribe_on method.

If you had an inscribe_on impl: delete it, and read on-handlers from the on_handlers slice inside inscribe_widget instead.

DsOn::get_body()

Previously returned &syn::Block directly. Now returns Option<&syn::Block> because on EventKind(cb) (callback-form) carries no body.

If you matched on the body unconditionally, switch to handling the None case — typically by reading the trailing element of get_args() as the callback expression.

DsAttr::name

Previously a non-optional syn::Ident. Now Option<syn::Ident> because positional attrs (text("hello")) carry no name.

If you read attr.name directly, match on the Option. The convenience name_str() -> Option<String> is the matching-friendly form.

Niche and match nodes

@name { … } and match expr { … } are AST nodes the trait now includes. If your DsRune impl predates them, the compiler will demand inscribe_niche and inscribe_match — the trait has no default impls.

Removed

These items are not in the language any more. If you find them in example code, it’s pre-current.

Source-of-truth

• Full version-by-version changelog: CHANGELOG.md
• Trait surface today: crates/xrune_nexus/src/ds_rune/mod.rs
• AST surface today: see The Runes