Add v0.1 skeleton: spec, parser/runtime, CLI, hello example, tests, CI

[minglong51]

Motivation

• Provide a minimal, well-structured v0.1 interpreter skeleton for ThreadLang to enable deterministic parsing and traceable runtime behavior.
• Support only the small language subset required to run the included hello example so future work can safely extend features.
• Make the project runnable and testable locally and in CI with no third-party runtime dependencies for v0.1.

Description

• Added packaging (pyproject.toml), a console script thread (src/threadlang/cli.py), and package exports (src/threadlang/__init__.py).
• Implemented dataclass AST nodes in src/threadlang/ast.py (Program, ContextAssign, Emit, StringLiteral, VariableRef, Concat).
• Implemented a minimal deterministic parser in src/threadlang/parser.py supporting thread Name { ... }, context { key = "string" }, emit text { ... }, context.<key>, inputs.<key>, and + concatenation, plus placeholder handling for inputs/rules/steps blocks.
• Implemented runtime in src/threadlang/runtime.py that evaluates the AST and returns RunResult(output, trace) with trace events (parse_ok, context_set, emit).
• Added docs (docs/spec.md, docs/grammar.ebnf), example program (examples/hello.thread), golden test (tests/test_golden_hello.py), and GitHub Actions workflow (.github/workflows/ci.yml).
• Updated README.md with local run/test instructions and the hello example command.

Testing

• Attempted python -m pip install -e . which failed in this environment due to network/proxy restrictions when resolving build dependencies.
• python -m pip install -e . --no-build-isolation succeeded in this environment.
• python -m pytest passed (1 test), and the golden test tests/test_golden_hello.py asserts result.output == "Hello, world!" and a trace sequence ["parse_ok", "context_set", "emit"].
• Executing the CLI example thread run examples/hello.thread --inputs name=world produced Hello, world! as expected.

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Codex Task

[minglong51]

Superseded — main has long since shipped past this v0.1 skeleton (v0.8 as of June 2026). Closing stale PR.