Refinement pass:
- DotAccess: unwraps Signal/Derived before field lookup
- UnaryOp: uses unification instead of manual matching
- Call: unifies each arg with param type, applies subst to return
- List: unifies all element types (not just first)
- If/else: unifies both branches, checks condition is Bool
- When/else: unifies body with else body, checks condition
- Match: unifies all arm types for consistency
- Assign: checks assigned value compatible with variable type
- ForIn: binds iteration variable from Array element type
Tests: 39 ds-types (up from 34), 164 workspace total, 0 failures
Type System Completion:
- Add unify() with occurs check for proper type variable binding
- Add apply_subst() to chase type variables through substitution map
- Add SignalInfo/SignalClass for graph-based signal classification
- Add check_program_with_signals() accepting optional signal graph data
- Push Dom effect handler scope automatically when checking view blocks
- Wire unification into BinOp, comparison, and logical operator inference
- Include List/Record literals in source signal heuristic
Tests: 34 ds-types tests (up from 11), 159 workspace total, 0 failures
- AST: When(cond, body) -> When(cond, body, Option<else_body>)
- Parser: optional 'else -> expr' after when body
- Codegen: reactive DOM swap with anchor comments
- Signal graph + type checker updated for 3-arg When
- Component prop signal wrapping: .value compatible accessors
- Added examples/when-else-demo.ds
Array access: Expr::Index in AST, [expr] postfix parsing, codegen for
reads (grid.value[i.value]) and writes (event handler assignments with
root signal extraction for stream diff broadcasting).
Timer: 'every N -> expr' declaration. Every keyword in lexer. EveryDecl
in AST. parse_every_decl in parser. setInterval codegen with DS.flush.
String interpolation: already committed separately.
Type checker: handles Expr::Index (infers array element type).
110 tests, 0 failures.
Phase 6 features:
- ForIn reactive list rendering: for item in items -> body
- Optional index binding: for item, idx in items -> body
- Component declarations: component Name(props) = body
- Component instantiation: ComponentUse { name, props }
Added across 5 crates:
- ds-parser: For/In/Component tokens, ForIn/ComponentDecl AST nodes
- ds-codegen: reactive list effect, component function emission
- ds-types: ForIn/ComponentUse type inference
- local_vars tracking for non-reactive for-in loop vars
Includes examples/list.ds showcasing for-in + when + signals.
