Extension Checklist¶

An executor implementation is considered Lace Extension Compatible when it satisfies all items in this checklist. Partial compatibility must be documented -- an executor may declare which sections it supports.

Spec version: 0.9.0

1. Extension Loading¶

[ ] Reads .laceext files listed in lace.config at startup
[ ] Fails with a clear error if a listed extension file is not found
[ ] Loads extensions in the order listed in config
[ ] Parses the TOML structure and validates it against the .laceext schema
[ ] Rejects .laceext files with unknown top-level sections (warning, not error)

2. Schema Additions¶

[ ] Registers extension fields with the validator at the declared targets
[ ] Accepts registered fields without error when extension is active
[ ] Emits unknown-field warnings (not errors) for extension fields when extension is inactive
[ ] Does not emit errors for unknown fields in options {} blocks regardless of extension state

3. Rule Body Language¶

[ ] Parses rule bodies and function bodies using the grammar in lace-extensions.md section 5.1
[ ] Executes for iteration with named binding; skips body when collection is null
[ ] Executes inline when expr as a guard that exits current scope on false/null
[ ] Executes block when expr: as a conditional block skip
[ ] Executes let $name = expr as an immutable local binding within current scope
[ ] Rejects rebinding the same $name in the same scope
[ ] Executes set $name = expr as reassignment of an existing binding (walks up scope chain)
[ ] Rejects set in rule bodies -- parse error
[ ] Rejects set on an unbound name -- runtime error
[ ] Executes emit target <- { fields } as an append to the target array
[ ] Rejects emit to paths not declared in [result] or result.runVars
[ ] Executes exit as immediate exit from rule body
[ ] Rejects exit inside function bodies -- parse error
[ ] Rejects return inside rule bodies -- parse error
[ ] Executes return expr inside function bodies only

4. Expressions¶

[ ] Evaluates all arithmetic operators with correct type rules (lace-extensions.md section 5.3, 5.4)
[ ] Evaluates all comparison operators with correct type rules
[ ] Evaluates and, or, not with short-circuit evaluation
[ ] Null propagation: field access, array index, array filter on null returns null (lace-extensions.md section 5.5)
[ ] null eq null evaluates to true
[ ] not null evaluates to true
[ ] Array filter [? condition] returns first matching element or null
[ ] Ternary a ? b : c evaluates correctly; falsy a (false or null) takes the c branch
[ ] String concatenation with +
[ ] No implicit type coercion -- incompatible types return null

5. Primitives¶

[ ] compare(a, b) returns correct op key for all comparable type pairs; null for null/incomparable inputs
[ ] map_get(map, key) returns correct value; falls back to "default"; null for absent/null
[ ] map_match(map, actual, expected, op) tries literal key, then op key, then "default" in order
[ ] is_null(v) returns bool correctly
[ ] type_of(v) returns correct type string for all value types
[ ] to_string(v) returns string representation for all value types
[ ] replace(str, pattern, replacement) performs string substitution; null-safe

6. Functions¶

[ ] Parses function definitions from [functions] section
[ ] Calls extension functions by name from rule bodies and other functions
[ ] Parameters bound as $param_name
[ ] return expr exits function and produces value
[ ] Function reaching end without return returns null
[ ] Rejects recursive calls (cycle detection at load time)
[ ] Functions cannot emit or access result directly

7. Hook Points¶

[ ] on before call fires before any chain method on a call executes
[ ] on call fires after all chain methods on a call complete
[ ] on before expect fires before each .expect() scope is evaluated
[ ] on expect fires after each .expect() scope is evaluated (once per scope, not once per method)
[ ] on before check / on check -- same as expect for .check()
[ ] on before assert / on assert fires per condition in .assert()
[ ] on before store / on store fires per entry in .store()
[ ] Rules from multiple extensions at the same hook are ordered per lace-extensions.md section 8.1.1 -- by explicit after / before qualifiers and implicit after edges from require, topo-sorted with ties broken deterministically (declaration order within a file, then extension name alphabetically). Executors must not rely on lace.config load order for determinism.
[ ] Rules within a single extension run in declaration order (unless explicit ordering qualifiers say otherwise)

8. Extension Variables¶

[ ] emit result.runVars <- { key: value } merges into runVars
[ ] Rejects keys not prefixed with {extension_name}. -- records warning, continues
[ ] Extension variables appear in final runVars map
[ ] Extension variables are not injected into the script's $var namespace
[ ] Values may be any JSON-serialisable shape (scalar, object, or array)

9. Configuration¶

[ ] Loads sibling {extName}.config file when present (lace-extensions.md section 2.3); absence is not an error
[ ] Reads [extensions.{name}] config section from lace.config
[ ] Merges .config defaults with lace.config overrides per lace-extensions.md section 11.1 (overrides win, defaults preserved for absent keys)
[ ] Provides merged config object to rule bodies containing the extension's config values
[ ] Resolves env:VARNAME and env:VARNAME:default in lace.config values at startup (not in .config defaults)

10. Result Conformance¶

[ ] emit result.actions.{key} initialises to [] if not yet present
[ ] Final result contains all emitted extension fields under actions
[ ] Extension variables appear in runVars with correct prefixes
[ ] Core result fields (calls, outcome, runVars script entries, startedAt, endedAt) are never mutated by extension rules