hakorune/docs/reference/language/quick-reference.md

Nyash Quick Reference (MVP)

Purpose

• One‑page practical summary for writing and implementing Nyash.
• Keep grammar minimal; clarify rules that often cause confusion.

Keywords (reserved)

• control: if, else, loop, match, case, break, continue, return
• decl: static, box, local, using, as
• lit: true, false, null, void

Expressions and Calls

• Function call: f(a, b)
• Method call: obj.m(a, b) — internally normalized to function form: Class.m(me: obj, a, b)
  • Default‑ON（P4）: Known 受信者かつ関数が一意に存在する場合に正規化（userbox 限定）。
  • それ以外（Unknown/core/user‑instance）は安全に BoxCall へフォールバック（挙動不変）。
  • 環境で無効化: NYASH_REWRITE_KNOWN_DEFAULT=0（開発時の切替用）。
  • バックエンド（VM/LLVM/Ny）は統一形状の呼び出しを受け取る。
• Member: obj.field or obj.m

Display & Conversion

• Human‑readable display: str(x)（推奨）/ x.str()
  • 既存の toString() は str() に正規化（Builder早期リライト）。
  • 互換: 既存の stringify() は当面エイリアス（内部で str() 相当へ誘導）。
• Debug表示（構造的・安定）: repr(x)（将来導入、devのみ）
• JSONシリアライズ: toJson(x)（文字列）/ toJsonNode(x)（構造）

Operators (precedence high→low)

• Unary: ! ~ -
• Multiplicative: * / %
• Additive: + -
• Compare: == != < <= > >=
• Logical: && || (short‑circuit, side‑effect aware)

Semicolons and ASI (Automatic Semicolon Insertion)

• Allowed to omit semicolon at:
  • End of line, before } or at EOF, when the statement is syntactically complete.
• Not allowed:
  • Line break immediately after a binary operator (e.g., 1 +\n2)
  • Ambiguous continuations; parser must Fail‑Fast with a clear message.

Truthiness (boolean context)

• Bool → itself
• Integer → 0 is false; non‑zero is true
• String → empty string is false; otherwise true
• Array/Map → non‑null is true (size is not consulted)
• null/void → false

Equality and Comparison

• == and != compare primitive values (Integer/Bool/String). No implicit cross‑type coercion.
• Box/Instance comparisons should use explicit methods (equals), or be normalized by the builder.
• Compare operators < <= > >= are defined on integers (MVP).

String and Numeric +

• If either side is String, + is string concatenation.
• If both sides are numeric, + is addition.
• Other mixes are errors (dev: warn; prod: error) — keep it explicit（必要なら str(x) を使う）。

Blocks and Control

• if (cond) { ... } [else { ... }]
• loop (cond) { ... } — minimal loop form
• match (expr) { case ... } — MVP (literals and simple type patterns)

Using / SSOT

• Dev/CI: file‑based using allowed for convenience.
• Prod: nyash.toml only. Duplicate imports or alias rebinding is an error.

Errors (format)

• Always: Error at line X, column Y: <message>
• For tokenizer errors, add the reason and show one nearby line if possible.

Dev/Prod toggles (indicative)

• NYASH_DEV=1 — developer defaults (diagnostics, tracing; behavior unchanged)
• NYASH_ENABLE_USING=1 — enable using resolver
• NYASH_ENTRY_ALLOW_TOPLEVEL_MAIN=1 — allow main as top‑level entry

Notes

• Keep the language small. Prefer explicit conversions (int(x), str(x), bool(x)) in standard helpers over implicit coercions.
• Builder rewrites method calls to keep runtime dispatch simple and consistent across backends.