forst-lang / forst / 24311749291

76%

Build Type

push

github

Committed by web-flow

Commit Message

feat(compiler)!: nominal error types (`error X { … }`) (#70)

* feat(compiler)!: nominal error types (error X { … })

Add user-defined nominal failure types with struct payloads: parse into
TypeDefErrorExpr, register with Error subtyping, unify/lookup and Go + TS
emit, fmt + LSP hover, and integration tests. Adds examples/in/nominal_error.ft
and task example:nominal-error.

docs(rfc): align errors architecture, normative RFC, hub README,
effect examples, ROADMAP experimental status, and testing rules with shipped
vs remaining RFC 02 work.

Example:

```forst
error NotPositive {
	message: String
}

func Test() {
	n := 0
	ensure n is GreaterThan(0) or NotPositive({
		message: "n must be greater than 0",
	})
}
```

* test: expand nominal error coverage

- compiler: assert examples/in/nominal_error.ft emits NotPositive struct, payload field, and error return
- parser: full-file parse of error typedef plus ensure … or nominal payload
- typechecker: CheckTypes on ensure/or arm; lock in IsTypeCompatible for same-shaped distinct nominals
- printer: printType for user nominal ident

Coverage Stats

224 of 405 new or added lines in 30 files covered. (55.31%)

2 existing lines in 2 files now uncovered.

16486 of 26381 relevant lines covered (62.49%)

19.96 hits per line