Tya v0.45 Specification

This document is the frozen specification for Tya v0.45, a user-facing polish release for the class-oriented namespace and entry-file model that shipped in v0.44.

Theme

v0.44 shipped the model: directory-as-package, PascalCase class files, lowercase script files, within-package bare class references, same-segment collision detection, and structured [TYA-EXXXX] diagnostic codes.

v0.45 lands the three v0.44 follow-ups that do not require a Tya-written compiler on the v0.44 surface:

1. Every examples/*.tya is on the new model.
2. Cross-file private class visibility is now enforced ([TYA-E0406]).
3. Five of the eight held-back stdlib packages are migrated to class form.

The remainder of the v0.44 follow-up work — the v02 self-host on the v0.44 surface, the string/array/dict stdlib migration that depends on it, the module keyword removal, and the docs/SPEC.md promotion — is scheduled into a later minor in the v1.0.0 prep window (see ROADMAP.md § v0.4x).

Goals

• G1. Migrate every examples/*.tya to the v0.44 model. Remove every module declaration from examples/.
• G2. Enforce cross-file private class visibility. A class beyond the file’s public class is private to its declaring file; references from any other file — including sibling files inside the same directory package — raise [TYA-E0406].
• G3. Migrate five concurrency-related stdlib packages (runtime, time, channel, sync, task) to the v0.44 class form. Update every caller and docs/STDLIB.md.

Non-Goals (deferred to v0.4x)

• A Tya-written compiler on the v0.44 surface (selfhost/v02/).
• Migration of string, array, dict to class form — these packages are still consumed by selfhost/v01/compiler.tya as single-file modules.
• Removal of the module keyword.
• Promotion of docs/v0.44/SPEC.md content into docs/SPEC.md.

G1 — Examples migration

Outcome

examples/util.tya (legacy module util) → examples/util/Util.tya (class form). examples/greeting.tya (legacy module greeting) → examples/greeting/Greeting.tya. Consumers updated to the <pkg>.<Class>.<member> surface:

# examples/use_module_decl.tya
import util

print(util.Util.foo)
print(util.Util.bar())

Acceptance

• find examples -name '*.tya' -exec grep -l '^module ' {} \; returns no matches.
• sh scripts/go_emit_examples_check.sh is green.
• go test ./... -count=1 is green.
• The self-host gate is green.

Notes

The Go tree-walking eval interpreter (internal/eval/) does not implement v0.44 class syntax. The two migrated examples (use_module.tya, use_module_decl.tya) are therefore removed from TestExamplesGolden; their codegen path remains covered by scripts/go_emit_examples_check.sh.

G2 — Cross-file private class enforcement

Diagnostic

[TYA-E0406] — checker. Reserved in v0.44, wired in v0.45.

Outcome

A class file’s non-public sibling classes cannot be referenced from outside the file that declared them — including sibling files inside the same directory package and external entry scripts.

Positive: a private class is reachable from its own file (call, member, extends).

Negative: every other cross-file reference raises [TYA-E0406] with the site / declaring-file pair.

Implementation

• ast.ClassDecl gains an OriginFile string field.
• The runner’s synthesizePackageSource returns a class-name → origin-file map alongside the synthesized source. The runner stashes the map on loadState.classOrigins keyed by synthesized package module name.
• runner.LoadUserSourceWithOrigins / runner.LoadSourceWithOrigins expose the map. After the merged source is re-parsed, runner.StampOriginFiles walks the AST and writes OriginFile onto every ClassDecl in a synthesized ModuleDecl.
• checker.classInfo gains originFile; predeclareModuleClass copies it from the AST.
• checker.checkCrossFilePrivate enforces the rule: a class is public iff its bare name + ".tya" equals its OriginFile; references to a private class from any other file raise [TYA-E0406]. Wired into checkClassCall, the within-package bare-Ident class lookup, the kindModule MemberExpr path, and the extends-parent resolution in checkClass.

Classes from single-file scripts or legacy module declarations leave OriginFile == "" and bypass the check.

Fixtures

Under tests/testdata/v45/:

• cross_file_private_positive.txtar — private class reachable from its own file (positive).
• cross_file_private_member.txtar — cross-file member access (negative).
• cross_file_private_extends.txtar — cross-file extends (negative).
• cross_file_private_external.txtar — entry script reaches into a package’s private class (negative).

G3 — stdlib migration (partial)

Migrated

Member access changes from pkg.member(args) to pkg.<Pkg>.member(args):

import runtime
stats = runtime.Runtime.gc_stats()

import time
t = time.Time.now()

import channel
c = channel.Channel.new(10)
channel.Channel.send(c, "hi")

import sync
m = sync.Sync.mutex()

import task
me = task.Task.current()

Callers updated in examples/, tests/, tests/testdata/, and docs/STDLIB.md. The legacy single-file stdlib/<pkg>.tya files are deleted.

Held back (to v0.4x)

string, array, dict remain at stdlib/<pkg>.tya (single file). selfhost/v01/compiler.tya still consumes them via single-file import and must do so until the v02 self-host upgrade lands.

Verification

go test ./... -count=1
go test ./tests -run TestSelfhostV01Scripts -count=1
go test ./tests -run TestSelfhostV02Scripts -count=1
sh scripts/go_emit_examples_check.sh

All four are green at the v0.45 release tag.

Release artifacts

• cmd/tya/main.go — const version = "0.45.0".
• docs/v0.45/SPEC.md — this file, frozen.
• docs/v0.45/RELEASE_NOTES.md — release-time summary.
• ROADMAP.md — v0.45 entry under Released; v0.4x Epic carries M8 + M6 remaining + M9 + M10.

Cross-References

• docs/v0.44/SPEC.md — the model itself.
• ROADMAP.md — Released § v0.45 mirrors this document at task-list granularity; Scheduled § v0.4x owns the carry-over.