Spec Update: Batch 05 — Statements & Control Flow

Date: 2026-04-16 Plans Referenced: Plan 120 (Option/Result patterns), Plan 122 (ownership), Plan 124 (reply), Plan 165 (struct destructuring), Plan 168 (shared) Source Files: ast.rs (Stmt enum, 34 variants), ast/store.rs (StoreKind, 6 variants) Sections Updated: Statements (Section 7), Control Flow (Section 8)

Old Content

Statements

• Listed 4 storage modifiers: let, mut, const, var
• Only expression, block statements

Control Flow

• if, for, while loops, loop, is pattern matching
• Pattern branches used -> (incorrect — should be =>)
• No struct destructuring, no Option/Result patterns, no when blocks
• Used println() instead of print()

New Content

Statements

• Updated to 6 storage modifiers: let, var, const, mut, shared (Plan 168), static
• Added return statement documentation
• Added reply statement for task RPC (Plan 124)
• Added break statement
• Added import statements (use, dep)
• Added type declaration statements
• Added extension statements (ext)
• Added comment statements
• Noted empty lines as statement separators

Control Flow

• Fixed pattern matching arrow syntax: -> → =>
• Replaced println() with print() throughout
• Removed while — documented for condition { } as replacement
• Added struct destructuring in patterns (Plan 165)
• Added Option pattern matching: Some(x) / None (Plan 120)
• Added Result pattern matching: Ok(value) / Err(msg) (Plan 120)
• Added when blocks

Stmt Variant Coverage

34 total variants now documented:

• Expr, If, For, Is, Store, Block, Fn, EnumDecl, TypeDecl, Union, Tag
• SpecDecl, Node, Use, Dep, OnEvents, Comment, Alias, TypeAlias
• EmptyLine, Break, Return, Reply, Ext
• WidgetDecl, MsgDecl, ModelBlock, ViewBlock (UI — Batch 12)
• TaskDef (Tasks — Batch 10)
• HashIf, HashFor, HashIs, HashBrace (Compile-time — Batch 11)

Notes

• while is NOT a keyword in Auto. The spec previously documented it incorrectly.
• All println() references replaced with print() (Auto syntax)
• Pattern matching uses => not -> (this was a documentation error)
• StoreKind has 6 variants: Let, Var, Const, Shared, CVar, Field