commit 1298b693880f77bb054b60ab2c778bf11d15226a
Author: sfja <sfja2004@gmail.com>
Date:   Fri Apr 10 02:13:26 2026 +0200

    init

diff --git a/demo.hlcsl b/demo.hlcsl
new file mode 100644
index 0000000..21a9019
--- /dev/null
+++ b/demo.hlcsl
@@ -0,0 +1,47 @@
+
+(def nand (a b vin) (r) (
+    (let (a_and_b) (relay_default_off a b))
+    (set r (relay_default_on a_and_b vin))
+))
+
+(def not (a) (r) (
+    (set r (nand a a))
+))
+
+(def and (a b) (r) (
+    (set r (not (nand a b)))
+))
+
+(def or (a b) (r) (
+    (set r (nand (not a) (not b)))
+))
+
+(def xor (a b) (r) (
+    (set r (and (or a b) (not (and a b))))
+))
+
+(def xor_optimized (a b) (r) (
+    (let (c) (nand a b))
+    (set r (nand (nand a c) (nand b c)))
+))
+
+(def half_add (a b) (r0 r1) (
+    (set r0 (xor a b))
+    (set r1 (and a b))
+))
+
+(def add (a b carry) (r0 r1) (
+    (let (d0 d1) (half_add a b))
+    (let (e0 e1) (half_add carry d0))
+    (set r0 e0)
+    (set r1 (or d1 e1))
+))
+
+(def add2 (a0 a1 b0 b1 carry_in) (r0 r1 carry_out) (
+    (let (d0 d1) (add a0 b0 carry_in))
+    (let (e0 e1) (add a1 b1 d1))
+    (set r0 d0)
+    (set r1 e0)
+    (set carry_out e1)
+))
+
diff --git a/deno.jsonc b/deno.jsonc
new file mode 100644
index 0000000..7ebf61b
--- /dev/null
+++ b/deno.jsonc
@@ -0,0 +1,5 @@
+{
+    "fmt": {
+        "indentWidth": 4
+    }
+}
\ No newline at end of file
diff --git a/src/ast.ts b/src/ast.ts
new file mode 100644
index 0000000..071dd4e
--- /dev/null
+++ b/src/ast.ts
@@ -0,0 +1,79 @@
+export interface Visitor {
+    visitDef?(def: Def): void | "stop";
+    visitStmt?(stmt: Stmt): void | "stop";
+    visitExpr?(expr: Expr): void | "stop";
+}
+
+export class Def {
+    constructor(
+        public line: number,
+        public ident: string,
+        public inputs: string[],
+        public outputs: string[],
+        public stmts: Stmt[],
+    ) {}
+
+    visit(v: Visitor) {
+        if (v.visitDef?.(this) === "stop") return;
+        for (const stmt of this.stmts) {
+            stmt.visit(v);
+        }
+    }
+}
+
+export class Stmt {
+    constructor(
+        public line: number,
+        public kind: StmtKind,
+    ) {}
+
+    visit(v: Visitor) {
+        if (v.visitStmt?.(this) === "stop") return;
+        this.visitSubtree(v);
+    }
+
+    visitSubtree(v: Visitor) {
+        const k = this.kind;
+        switch (k.tag) {
+            case "Set":
+                k.subject.visit(v);
+                k.expr.visit(v);
+                break;
+            case "Let":
+                k.expr.visit(v);
+                break;
+            default:
+                k satisfies never;
+        }
+    }
+}
+
+export type StmtKind =
+    | { tag: "Set"; subject: Expr; expr: Expr }
+    | { tag: "Let"; idents: string[]; expr: Expr };
+
+export class Expr {
+    constructor(
+        public line: number,
+        public kind: ExprKind,
+    ) {}
+
+    visit(v: Visitor) {
+        if (v.visitExpr?.(this) === "stop") return;
+        const k = this.kind;
+        switch (k.tag) {
+            case "Ident":
+                break;
+            case "Call":
+                k.callee.visit(v);
+                k.args.map((e) => e.visit(v));
+                break;
+            default:
+                k satisfies never;
+        }
+    }
+}
+
+export type ExprKind =
+    | { tag: "Ident"; ident: string }
+    | { tag: "Call"; callee: Expr; args: Expr[] };
diff --git a/src/front.ts b/src/front.ts
new file mode 100644
index 0000000..f2748f0
--- /dev/null
+++ b/src/front.ts
@@ -0,0 +1,308 @@
+import { Def, Expr, Stmt } from "./ast.ts";
+
+function appended<T>(vs: T[], v: T): T[] {
+    vs.push(v);
+    return vs;
+}
+
+export type Tok = {
+    ty: string;
+    text: string;
+    line: number;
+};
+
+export function tokenize(text: string): Tok[] {
+    return text
+        .replace(/\/\/[^\n]*/g, "")
+        .replace(/[\(\)\n]/g, " $& ")
+        .split(/[ \t\r]+/)
+        .filter((tok) => tok !== "")
+        .reduce<[{ tok: string; line: number }[], number]>(
+            ([toks, line], tok) =>
+                tok != "\n"
+                    ? [appended(toks, { tok, line }), line]
+                    : [toks, line + 1],
+            [[], 1],
+        )[0]
+        .map(({ tok, line }) => ({ ty: tok, text: tok, line }))
+        .map((tok) => {
+            if (/^[a-zA-Z_][a-zA-Z_0-9]*$/.test(tok.text)) {
+                tok.ty = "ident";
+            }
+            return tok;
+        });
+}
+
+export type SExpr = {
+    line: number;
+    ty: "Ident" | "List";
+    ident?: string;
+    exprs?: SExpr[];
+};
+
+function parseSExpr(toks: Tok[]): [Tok[], SExpr | null] {
+    if (toks.length == 0) {
+        return [toks, null];
+    }
+    const line = toks[0].line;
+    if (toks[0].ty === "ident") {
+        const ident = toks[0].text;
+        return [toks.slice(1), { line, ty: "Ident", ident }];
+    } else if (toks[0].ty === "(") {
+        toks = toks.slice(1);
+        const exprs: SExpr[] = [];
+        while (toks.length != 0 && toks[0].ty !== ")") {
+            let expr: SExpr | null;
+            [toks, expr] = parseSExpr(toks);
+            if (!expr) {
+                throw new Error(`expected expression on line ${line}`);
+            }
+            exprs.push(expr);
+        }
+        if (toks.length == 0 || toks[0].ty != ")") {
+            throw new Error(
+                `expected ')' on line ${
+                    toks.at(0)?.line ?? "(eof)"
+                }, '(' on line ${line}`,
+            );
+        }
+        return [toks.slice(1), { line, ty: "List", exprs }];
+    } else {
+        throw new Error(`malformed on line ${line}`);
+    }
+}
+
+export function parseSExprs(toks: Tok[]): SExpr[] {
+    const exprs: SExpr[] = [];
+    while (toks.length != 0) {
+        let expr: SExpr | null;
+        [toks, expr] = parseSExpr(toks);
+        exprs.push(expr!);
+    }
+    return exprs;
+}
+
+class SExprMatcher {
+    private failed = false;
+    private captures = new Map<string, SExpr>();
+
+    constructor(private s: SExpr) {}
+
+    match(): Record<string, SExpr> | null {
+        return this.failed ? null : Object.fromEntries(this.captures.entries());
+    }
+
+    ident(val?: string): this {
+        if (this.s.ty !== "Ident" || val && this.s.ident! !== val) {
+            this.failed = true;
+            return this;
+        }
+        return this;
+    }
+
+    list(length?: number): this {
+        if (
+            this.s.ty !== "List" || (length && this.s.exprs!.length !== length)
+        ) {
+            this.failed = true;
+            return this;
+        }
+        return this;
+    }
+
+    at(idx: number, func?: (s: SExprMatcher) => SExprMatcher): this {
+        if (this.s.ty !== "List" || idx >= this.s.exprs!.length) {
+            this.failed = true;
+            return this;
+        }
+        if (func) {
+            const inner = new SExprMatcher(this.s.exprs![idx]);
+            func(inner);
+            for (const [key, val] of inner.captures.entries()) {
+                this.captures.set(key, val);
+            }
+            this.failed = this.failed || inner.failed;
+        }
+        return this;
+    }
+
+    all(func: (s: SExprMatcher) => SExprMatcher): this {
+        if (this.s.ty !== "List") {
+            this.failed = true;
+            return this;
+        }
+        for (const s1 of this.s.exprs!) {
+            const inner = new SExprMatcher(s1);
+            func(inner);
+            for (const [key, val] of inner.captures.entries()) {
+                this.captures.set(key, val);
+            }
+        }
+        return this;
+    }
+
+    capture(id: string): this {
+        this.captures.set(id, this.s);
+        return this;
+    }
+}
+
+export function parseAst(ss: SExpr[]): Def[] {
+    const defs: Def[] = [];
+    for (const s of ss) {
+        defs.push(parseDef(s));
+    }
+    return defs;
+}
+
+function parseDef(s: SExpr): Def {
+    const m = new SExprMatcher(s)
+        .list(5)
+        .at(0, (s) => s.ident("def"))
+        .at(1, (s) => s.ident().capture("ident"))
+        .at(2, (s) => s.all((s) => s.ident()).capture("inputs"))
+        .at(3, (s) => s.all((s) => s.ident()).capture("outputs"))
+        .at(4, (s) => s.list().capture("stmts"))
+        .match();
+    if (!m) {
+        throw new Error(`malformed def on line ${s.line}`);
+    }
+    return new Def(
+        s.line,
+        m.ident.ident!,
+        m.inputs.exprs!.map((s) => s.ident!),
+        m.outputs.exprs!.map((s) => s.ident!),
+        m.stmts.exprs!.map((s) => parseStmt(s)),
+    );
+}
+
+function parseStmt(s: SExpr): Stmt {
+    const set_match = new SExprMatcher(s)
+        .list(3)
+        .at(0, (s) => s.ident("set"))
+        .at(1, (s) => s.ident().capture("subject"))
+        .at(2, (s) => s.capture("expr"))
+        .match();
+    if (set_match) {
+        const m = set_match;
+        return new Stmt(
+            s.line,
+            {
+                tag: "Set",
+                subject: parseExpr(m.subject),
+                expr: parseExpr(m.expr),
+            },
+        );
+    }
+    const let_match = new SExprMatcher(s)
+        .list(3)
+        .at(0, (s) => s.ident("let"))
+        .at(1, (s) => s.all((s) => s.ident()).capture("idents"))
+        .at(2, (s) => s.capture("expr"))
+        .match();
+    if (let_match) {
+        const m = let_match;
+
+        return new Stmt(
+            s.line,
+            {
+                tag: "Let",
+                idents: m.idents.exprs!.map((s) => s.ident!),
+                expr: parseExpr(m.expr),
+            },
+        );
+    }
+    throw new Error(`malformed statement on line ${s.line}`);
+}
+
+function parseExpr(s: SExpr): Expr {
+    if (s.ty === "Ident") {
+        return new Expr(s.line, { tag: "Ident", ident: s.ident! });
+    } else if (s.ty === "List") {
+        if (s.exprs!.length === 0) {
+            throw new Error(`empty expression not allowed, on line ${s.line}`);
+        }
+        if (s.exprs![0].ty !== "Ident") {
+            throw new Error(`callee must be an identifier, on line ${s.line}`);
+        }
+        return new Expr(
+            s.line,
+            {
+                tag: "Call",
+                callee: parseExpr(s.exprs![0]),
+                args: s.exprs!.slice(1).map((s) => parseExpr(s)),
+            },
+        );
+    } else {
+        throw new Error(`expected expression, on line ${s.line}`);
+    }
+}
+
+export function resolve(defs: Def[]): Map<Def, Map<Expr, Sym>> {
+    const defSyms = new Map<string, Def>();
+    for (const def of defs) {
+        defSyms.set(def.ident, def);
+    }
+    const resols = new Map<Def, Map<Expr, Sym>>();
+    for (const def of defs) {
+        const defResolver = new DefResolver(def, defSyms);
+        defResolver.resolve();
+        resols.set(def, defResolver.resols);
+    }
+    return resols;
+}
+
+export type Sym =
+    | { tag: "Builtin" }
+    | { tag: "Input"; idx: number }
+    | { tag: "Output"; idx: number }
+    | { tag: "Node"; stmt: Stmt; idx: number }
+    | { tag: "Def"; def: Def };
+
+class DefResolver {
+    private syms = new Map<string, Sym>([
+        ["relay_default_off", { tag: "Builtin" }],
+        ["relay_default_on", { tag: "Builtin" }],
+    ]);
+    public resols = new Map<Expr, Sym>();
+
+    constructor(private def: Def, private defSyms: Map<string, Def>) {}
+
+    resolve() {
+        for (const [idx, ident] of this.def.inputs.entries()) {
+            this.syms.set(ident, { tag: "Input", idx });
+        }
+        for (const [idx, ident] of this.def.outputs.entries()) {
+            this.syms.set(ident, { tag: "Output", idx });
+        }
+        const { syms, defSyms, resols } = this;
+        this.def.visit({
+            visitStmt(stmt) {
+                stmt.visitSubtree(this);
+                if (stmt.kind.tag === "Let") {
+                    for (const [idx, ident] of stmt.kind.idents.entries()) {
+                        syms.set(ident, { tag: "Node", stmt, idx });
+                    }
+                }
+                return "stop";
+            },
+            visitExpr(expr) {
+                if (expr.kind.tag === "Ident") {
+                    const sym = syms.get(expr.kind.ident);
+                    if (sym) {
+                        resols.set(expr, sym);
+                        return;
+                    }
+                    const defSym = defSyms.get(expr.kind.ident);
+                    if (defSym) {
+                        resols.set(expr, { tag: "Def", def: defSym });
+                        return;
+                    }
+                    throw new Error(
+                        `unresolved identifier '${expr.kind.ident}', on line ${expr.line}`,
+                    );
+                }
+            },
+        });
+    }
+}
diff --git a/src/main.ts b/src/main.ts
new file mode 100644
index 0000000..315dbfb
--- /dev/null
+++ b/src/main.ts
@@ -0,0 +1,220 @@
+import * as front from "./front.ts";
+import * as ast from "./ast.ts";
+
+class Ins {
+    constructor(
+        public line: number,
+        public kind: InsKind,
+    ) {}
+}
+
+type InsKind =
+    | { tag: "Input"; idx: number }
+    | { tag: "Set"; idx: number; value: Ins }
+    | { tag: "RelayDefaultOff" | "RelayDefaultOn"; args: Ins[] }
+    | { tag: "Call"; def: ast.Def; args: Ins[] }
+    | { tag: "Elem"; value: Ins; idx: number };
+
+class InsCx {
+    public insts: Ins[] = [];
+
+    makeInput(line: number, idx: number): Ins {
+        return this.make(line, { tag: "Input", idx });
+    }
+    makeSet(line: number, idx: number, value: Ins): Ins {
+        return this.make(line, { tag: "Set", idx, value });
+    }
+    makeRelayDefaultOff(line: number, args: Ins[]): Ins {
+        return this.make(line, { tag: "RelayDefaultOff", args });
+    }
+    makeRelayDefaultOn(line: number, args: Ins[]): Ins {
+        return this.make(line, { tag: "RelayDefaultOn", args });
+    }
+    makeCall(line: number, def: ast.Def, args: Ins[]): Ins {
+        return this.make(line, { tag: "Call", def, args });
+    }
+    makeElem(line: number, value: Ins, idx: number): Ins {
+        return this.make(line, { tag: "Elem", value, idx });
+    }
+
+    private make(line: number, kind: InsKind) {
+        const ins = new Ins(line, kind);
+        this.insts.push(ins);
+        return ins;
+    }
+
+    pretty(): string {
+        let result = "";
+        let regIds = 0;
+        const insRegs = new Map<Ins, number>();
+
+        const r = (i: Ins): string => {
+            if (!insRegs.has(i)) {
+                insRegs.set(i, regIds++);
+            }
+            return `%${insRegs.get(i)!}`;
+        };
+
+        for (const ins of this.insts) {
+            switch (ins.kind.tag) {
+                case "Input":
+                    result += `  ${r(ins)} = input ${ins.kind.idx}\n`;
+                    break;
+                case "Set":
+                    result += `  set ${ins.kind.idx}, ${r(ins.kind.value)}\n`;
+                    break;
+                case "RelayDefaultOff":
+                    result += `  ${r(ins)} = relay_default_off ${
+                        r(ins.kind.args[0])
+                    } ${r(ins.kind.args[1])}\n`;
+                    break;
+                case "RelayDefaultOn":
+                    result += `  ${r(ins)} = relay_default_on ${
+                        r(ins.kind.args[0])
+                    } ${r(ins.kind.args[1])}\n`;
+                    break;
+                case "Call":
+                    result += `  ${r(ins)} = call @${ins.kind.def.ident} ${
+                        r(ins.kind.args[0])
+                    } ${r(ins.kind.args[1])}\n`;
+                    break;
+                case "Elem":
+                    result += `  ${r(ins)} = elem ${
+                        r(ins.kind.value)
+                    } ${ins.kind.idx}\n`;
+                    break;
+            }
+        }
+        return result;
+    }
+}
+
+class DefLowerer {
+    private symIns = new Map<front.Sym, Ins>();
+    private letIns = new Map<ast.Stmt, Ins[]>();
+
+    constructor(
+        private cx: InsCx,
+        private def: ast.Def,
+        private resols: Map<ast.Expr, front.Sym>,
+    ) {}
+
+    lower() {
+        for (const stmt of this.def.stmts) {
+            this.lowerStmt(stmt);
+        }
+    }
+
+    lowerStmt(stmt: ast.Stmt) {
+        switch (stmt.kind.tag) {
+            case "Set": {
+                const re = this.resols.get(stmt.kind.subject)!;
+                switch (re.tag) {
+                    case "Output":
+                        this.cx.makeSet(
+                            stmt.line,
+                            re.idx,
+                            this.lowerExpr(stmt.kind.expr),
+                        );
+                        break;
+                    case "Builtin":
+                    case "Input":
+                    case "Node":
+                    case "Def":
+                        throw new Error();
+                }
+                break;
+            }
+            case "Let": {
+                const value = this.lowerExpr(stmt.kind.expr);
+                this.letIns.set(
+                    stmt,
+                    stmt.kind.idents.map((_, i) =>
+                        this.cx.makeElem(stmt.line, value, i)
+                    ),
+                );
+                break;
+            }
+            default:
+                stmt.kind satisfies never;
+        }
+    }
+
+    lowerExpr(expr: ast.Expr): Ins {
+        switch (expr.kind.tag) {
+            case "Ident": {
+                const re = this.resols.get(expr)!;
+                switch (re.tag) {
+                    case "Input":
+                        return this.cx.makeInput(expr.line, re.idx);
+                    case "Node": {
+                        return this.letIns.get(re.stmt)![re.idx];
+                    }
+                    case "Builtin":
+                    case "Output":
+                    case "Def":
+                        throw new Error();
+                }
+                break;
+            }
+            case "Call": {
+                const re = this.resols.get(expr.kind.callee)!;
+                switch (re.tag) {
+                    case "Builtin": {
+                        if (expr.kind.callee.kind.tag !== "Ident") {
+                            throw new Error();
+                        }
+                        switch (expr.kind.callee.kind.ident) {
+                            case "relay_default_off":
+                                return this.cx.makeRelayDefaultOff(
+                                    expr.line,
+                                    expr.kind.args.map((expr) =>
+                                        this.lowerExpr(expr)
+                                    ),
+                                );
+                            case "relay_default_on":
+                                return this.cx.makeRelayDefaultOn(
+                                    expr.line,
+                                    expr.kind.args.map((expr) =>
+                                        this.lowerExpr(expr)
+                                    ),
+                                );
+                            default:
+                                throw new Error();
+                        }
+                        break;
+                    }
+                    case "Def": {
+                        return this.cx.makeCall(
+                            expr.line,
+                            re.def,
+                            expr.kind.args.map((expr) => this.lowerExpr(expr)),
+                        );
+                        break;
+                    }
+                    case "Input":
+                    case "Output":
+                    case "Node":
+                        throw new Error();
+                }
+                break;
+            }
+            default:
+                expr.kind satisfies never;
+        }
+        throw new Error();
+    }
+}
+
+const text = await Deno.readTextFile(Deno.args[0]);
+const toks = front.tokenize(text);
+const sexprs = front.parseSExprs(toks);
+const defs = front.parseAst(sexprs);
+const resols = front.resolve(defs);
+
+for (const def of defs) {
+    console.log(`${def.ident}:`);
+    const cx = new InsCx();
+    new DefLowerer(cx, def, resols.get(def)!).lower();
+    console.log(cx.pretty());
+}