Moss 0.7.3 Release

Moss 0.7.3 is the first release with an active Moss-written frontend.
The lexer, parser, and checker written in Moss are selectable via --frontend moss
on tokens, ast, check, compile, and run commands. The host (Python)
frontend remains the default and serves as the differential-verification baseline.

What's new since 0.5.0

Active Moss frontend (0.7 series)

• moss tokens --frontend moss — Moss-written lexer, token streams match host
• moss ast --frontend moss — Moss-written parser, full declaration trees
• moss check --frontend moss — Moss-written checker with diagnostics
• moss compile --frontend moss — Moss frontend → bytecode → .mbc
• moss run --frontend moss — Moss frontend → compiler → VM execution
• 6/9 example programs produce identical runtime output via Moss frontend

Trust bundles (0.5.7–0.5.8)

• moss trust <file> — machine-verifiable JSON bundle (check + trace + golden + lock + selfhost)
• moss trust-project <dir> — project-wide trust verification
• Source SHA-256 binding, lock verification, 5-dimension selfhost comparison

VM unification (0.5.5–0.5.6)

• All 12 commands run on a unified bytecode VM
• Tree-walking interpreter retired
• 32-opcode stack-machine ISA with .mbc binary format

Moss Playground (0.6.0)

• moss playground — browser-based trust report viewer (port 8766)
• Built-in examples, file upload, one-click Trust

Studio refresh (0.6.1–0.6.2)

• Complete visual refresh: Moss dark theme
• Trust tab with five-gate verification report
• Ctrl+Enter run, Ctrl+S save, clickable diagnostics

Backtick interpolation (0.5.5)

• `Hello {name}!` with multiline support and escape sequences
• |> pipe operator, \x -> expr lambda, arrow function body fn f(x) = expr

Install

From source (requires Python 3.12+)

git clone https://github.com/Fujo930/moss-lang.git
cd moss-lang
git checkout ds-Mosslang
pip install -e .

Windows standalone (no Python required)

Download Moss-0.7.3-Windows-Portable.zip or Moss-0.7.3-Windows-Setup.exe
from the Releases page.

Verification

python -m pytest tests/test_mosslang.py -q
# 129 passed, 18 subtests

python -m mosslang.cli selfhost --quick
# 5/5 sketch tests pass

python -m mosslang.cli selfhost-compare examples
# all examples pass host/self-host comparison

python -m mosslang.cli trust-project .
# 7/7 files trusted

Known limitations

• Moss frontend: For/While/If statement bodies not captured by Moss statement parser
  (affects lists_demo, map_demo, text_fs_demo via --frontend moss)
• Windows-only installer (macOS/Linux support planned for 0.8)
• No typed Python FFI yet (planned 0.8)

Commands

moss run/check/test/tokens/ast/trace/compile [--frontend host|moss]
moss trust/trust-project
moss studio/playground/repl
moss golden/docs/format
moss selfhost/selfhost-compare
moss project-check/run/test/init/info/lock/format
moss-lsp

Built by DeepSeek (Codex & Kun) and Reasonix in collaboration with Fujo930.