compile.phi

@@ -1,52 +1,17 @@
 
-(fn dbg (msg) (do
-    (if is_phi_compiler (do
-        (call println "dbg: %" msg)
-    ))
-))
-
 (fn Emitter (ast filename) (do
     (let output ())
 
     (let (enter_scope leave_scope define_sym get_sym print_syms) (call Syms))
 
     (let (let_node_reg_count let_node_reg_increment) (call Counter))
-    (let (sym_id_count sym_id_increment) (call Counter))
-
-    (let builtin_syms (
-        ("format" "builtinFormat")
-        ("print" "builtinPrint")
-        ("println" "builtinPrintln")
-        ("panic" "builtinPanic")
-        ("read_text_file" "builtinReadTextFile")
-        ("write_text_file" "builtinWriteTextFile")
-        ("push" "builtinPush")
-        ("at" "builtinAt")
-        ("set" "builtinSet")
-        ("len" "builtinLen")
-        ("string_to_int" "builtinStringToInt")
-        ("char_code" "builtinCharCode")
-        ("strings_join" "builtinStringsJoin")
-        ("get_args" "builtinGetArgs")
-    ))
 
     (fn generate () (do
         (call emit "#!/usr/bin/env node\n")
-        (call emit "import { Runtime } from \"./runtime.js\";\n")
+        (call emit "import { Runtime } from \"./runtime.js\"\n")
-        (call emit "const runtime = new Runtime({ filename: \"")
+        (call emit "const runtime = new Runtime(\"")
         (call emit filename)
-        (call emit "\" });\n")
+        (call emit "\")\n")
-
-        (for (ident builtin_id) builtin_syms (do
-            (call define_builtin ident builtin_id)
-        ))
-
-        (let is_phi_compiler_sym_id (call define_let "is_phi_compiler" 0))
-        (call emit (call format
-            "let _is_phi_compiler% = { type: \"bool\", value: true };\n"
-            is_phi_compiler_sym_id
-        ))
-
         (call discover_syms ast)
         (call emit_exprs ast)
         (return (call strings_join output))
@@ -67,8 +32,8 @@
             (if (== (call len s) 0) (return))
             (let ((_ _ id)) s)
             (if (== id "fn") (do
-                (let (_ (_ _ ident) (_ _ params) body) s)
+                (let (_ (_ _ name) (_ _ params) body) s)
-                (call define_fn ident line)
+                (call define_sym name ("fn" name line))
             ))
         ))
     ))
@@ -77,10 +42,10 @@
         (let (ty line) expr)
         (if (== ty "list") (do
             (call emit_list expr)
-        ) (if (== ty "int") (do
+        ) (if (== ty "int") (
             (let (_ _ value) expr)
             (call emit (call format "({ type: \"int\", value: % })" value))
-        ) (if (== ty "string") (do
+        ) (if (== ty "string") (
             (let (_ _ value) expr)
             (call emit (call format "({ type: \"string\", value: \"%\" })" (call string_escape value)))
         ) (if (== ty "ident") (do
@@ -103,16 +68,16 @@
                 (call panic "undefined symbol '%' on line %" value line)
             ))
 
-            (let (sym_id sym_ty) sym)
+            (let (sym_ty) sym)
             (if (== sym_ty "builtin") (do
-                (let (_ _ id) sym)
+                (let (_ id) sym)
                 (call emit (call format "((...args) => runtime.%(...args))" id))
             ) (if (== sym_ty "fn") (do
-                (call emit (call format "_%%" value sym_id))
+                (call emit (call format "_%" value))
             ) (if (== sym_ty "param") (do
-                (call emit (call format "_%%" value sym_id))
+                (call emit (call format "_%" value))
             ) (if (== sym_ty "let") (do
-                (call emit (call format "_%%" value sym_id))
+                (call emit (call format "_%" value))
             ) (do
                 (call panic "not implemented '%'" sym_ty)
             )))))
@@ -129,33 +94,30 @@
         ))
         (let ((id_ty _ id)) s)
         (if (!= id_ty "ident") (do
-            (call emit_list_literal s)
+            (call emit "({ type: \"list\", values: [] })")
             (return)
         ))
         (if (== id "fn") (do
-            (let (_ (_ _ ident) (_ _ params) body) s)
+            (let (_ (_ _ name) (_ _ params) body) s)
-
+            (call emit (call format "function _%(" name))
-            (let sym (call get_sym ident))
-            (let (sym_id) sym)
-
-            (call emit (call format "function _%%(" ident sym_id))
 
             (call enter_scope)
 
             (let first true)
-            (for (_ _ ident) params (do
+            (for (_ _ name) params (do
                 (if (not first) (do
                     (call emit ", ")
                 ))
                 (= first false)
 
-                (let sym_id (call define_param ident line))
+                (call emit (call format "_%" name))
-                (call emit (call format "_%%" ident sym_id))
+
+                (call define_sym name ("param" name line))
             ))
 
 
-            (call emit ") {\n")
+            (call emit (call format ") {\n" name))
-            (call emit (call format "runtime.pushCall(\"%\");\n" ident))
+            (call emit (call format "runtime.pushCall(\"%\");\n" name))
 
             (call emit_expr body)
             (call emit ";\nruntime.popCall();\nreturn { type: \"null\" };\n}")
@@ -165,7 +127,7 @@
             (let (_ pat expr) s)
             (let reg (call let_node_reg_count))
             (call let_node_reg_increment)
-            (call emit (call format "const r_% = " reg))
+            (call emit (call format "let r_% = " reg))
             (call emit_expr expr)
             (call emit_let_node pat reg)
         ) (if (== id "do") (do
@@ -175,22 +137,14 @@
             (call leave_scope)
         ) (if (== id "for") (do
             (let (_ pat expr body) s)
-
+            (call enter_scope)
-            (let reg (call let_node_reg_count))
+            (call emit "for (let ")
-            (call let_node_reg_increment)
+            (call emit_pat pat)
-            (call emit (call format "for (const r_% of " reg))
+            (call emit " of ")
             (call emit_expr expr)
-            (call emit ".values) {")
+            (call emit ".values) {\n")
-
-            (call enter_scope)
-            (call emit_let_node pat reg)
-            (call enter_scope)
-
-            (call emit ";\n")
             (call emit_expr body)
             (call emit "}")
-
-            (call leave_scope)
             (call leave_scope)
         ) (if (== id "loop") (do
             (let (_ body) s)
@@ -199,9 +153,9 @@
             (call emit "}")
         ) (if (== id "if") (do
             (let (_ cond truthy falsy) s)
-            (call emit "if (runtime.truthy(")
+            (call emit "if (")
             (call emit_expr cond)
-            (call emit ")) {\n")
+            (call emit ") {\n")
             (call emit_expr truthy)
             (call emit "}")
             (if (!= falsy null) (do
@@ -251,17 +205,17 @@
         ) (if (== id "or") (do
             (let (_ left right) s)
             (call emit (call format "(runtime.setLine(%)" line))
-            (call emit ", { type: \"bool\", value: runtime.truthy(")
+            (call emit ", { type: \"bool\", value: this.runtime.truthy(")
             (call emit_expr left)
-            (call emit ") || runtime.truthy(")
+            (call emit ") || this.runtime.falsy(")
             (call emit_expr right)
             (call emit ") })")
         ) (if (== id "and") (do
             (let (_ left right) s)
             (call emit (call format "(runtime.setLine(%)" line))
-            (call emit ", { type: \"bool\", value: runtime.truthy(")
+            (call emit ", { type: \"bool\", value: this.runtime.truthy(")
             (call emit_expr left)
-            (call emit ") && runtime.truthy(")
+            (call emit ") && this.runtime.falsy(")
             (call emit_expr right)
             (call emit ") })")
         ) (if (== id "==") (do
@@ -286,11 +240,6 @@
             (call emit_expr expr)
             (call emit ")")
         ) (do
-            (call emit_list_literal s)
-        ))))))))))))))))))))))))
-    ))
-
-    (fn emit_list_literal (s) (do
             (call emit "({ type: \"list\", values: [")
             (let first true)
             (for e s (do
@@ -302,6 +251,7 @@
                 (call emit_expr e)
             ))
             (call emit "] })")
+        ))))))))))))))))))))))))
     ))
 
     (fn emit_let_node (pat base_reg) (do
@@ -311,35 +261,16 @@
 
             (if (== ident "_") (return))
 
-            (let sym_id (call define_let ident line))
+            (call emit (call format ";\nlet _% = r_%" ident base_reg))
-            (call emit (call format ";\nlet _%% = r_%" ident sym_id base_reg))
+            (call define_sym ident ("let" line))
         ) (if (== pat_ty "list") (do
             (let (_ _ pats) pat)
 
-            //(call emit (call format
-            //    (+ ";\nif (r_%.type !== \"list\") {\nruntime.setLine(%);"
-            //        "\nruntime.panic(\"expected list\");\n}\n")
-            //    base_reg
-            //    line
-            //))
-            //(call emit (call format
-            //    (+ ";\nif (% > r_%.values.length) {\nruntime.setLine(%);\nruntime.panic"
-            //        "(`expected % elements, got ${r_%.values.length}`);\n}\n")
-            //    (call len pats)
-            //    base_reg
-            //    line
-            //    (call len pats)
-            //    base_reg
-            //))
-
             (let i 0)
             (for pat pats (do
                 (let reg (call let_node_reg_count))
                 (call let_node_reg_increment)
-                (call emit (call format
+                (call emit (call format ";\nlet r_% = r_%.values[%]" reg base_reg i))
-                    ";\nconst r_% = r_%.values[%] ?? { type: \"null\"}"
-                    reg base_reg i
-                ))
                 (call emit_let_node pat reg)
                 (+= i 1)
             ))
@@ -367,64 +298,59 @@
         (if (== sym null) (do
             (call panic "could not find symbol '%' on line %" ident line)
         ))
-        (let (sym_id sym_type sym_ident _) sym)
+        (let (sym_type sym_ident _) sym)
         (if (== sym_type "let") (do
-            (call emit (call format "(_%% = " sym_ident sym_id))
+            (call emit (call format "(_% = runtime.assignValue(" sym_ident))
             (if (== id "=") (do
                 (call emit_expr expr)
             ) (if (== id "+") (do
-                (call emit (call format "runtime.opAdd(_%%, " sym_ident sym_id))
+                (call emit (call format "runtime.opAdd(_%, " sym_ident))
                 (call emit_expr expr)
                 (call emit ")")
             ) (if (== id "-") (do
-                (call emit (call format "runtime.opSub(_%%, " sym_ident sym_id))
+                (call emit (call format "runtime.opSub(_%, " sym_ident))
                 (call emit_expr expr)
                 (call emit ")")
             ) (do
                 (call panic "not implemented")
             ))))
-            (call emit ")")
+            (call emit "))")
         ) (do
             (call panic "cannot assign to symbol '%' on line %" sym_ident line)
         ))
     ))
 
+    (fn emit_pat (pat) (do
+        (let (ty) pat)
+        (if (== ty "ident") (do
+            (let (_ line name) pat)
+            (if (== name "_") (do
+                (return)
+            ))
+            (call emit (call format "_%" name))
+            (call define_sym name ("let" name line))
+        ) (if (== ty "list") (do
+            (let (_ _ pats) pat)
+            (call emit "[")
+            (let first true)
+            (for pat pats (do
+                (if (not first) (do
+                    (call emit ", ")
+                ))
+                (= first false)
+
+                (call emit_pat pat)
+            ))
+            (call emit "]")
+        ) (do
+            (call panic "cannot assign to '%'" pat)
+        )))
+    ))
+
     (fn emit (str) (do
         (call push output str)
     ))
 
-    (fn define_builtin (ident builtin_id) (do
-        (let sym_id (call sym_id_count))
-        (call sym_id_increment)
-
-        (call define_sym ident (sym_id "builtin" builtin_id))
-        (return sym_id)
-    ))
-
-    (fn define_fn (ident line) (do
-        (let sym_id (call sym_id_count))
-        (call sym_id_increment)
-
-        (call define_sym ident (sym_id "fn" ident line))
-        (return sym_id)
-    ))
-
-    (fn define_param (ident line) (do
-        (let sym_id (call sym_id_count))
-        (call sym_id_increment)
-
-        (call define_sym ident (sym_id "param" ident line))
-        (return sym_id)
-    ))
-
-    (fn define_let (ident line) (do
-        (let sym_id (call sym_id_count))
-        (call sym_id_increment)
-
-        (call define_sym ident (sym_id "let" ident line))
-        (return sym_id)
-    ))
-
     (return (generate))
 ))
 
@@ -443,7 +369,22 @@
 ))
 
 (fn Syms () (do
-    (let syms (null ()))
+    (let syms (null (
+        ("format" ("builtin" "builtinFormat"))
+        ("print" ("builtin" "builtinPrint"))
+        ("println" ("builtin" "builtinPrintln"))
+        ("panic" ("builtin" "builtinPanic"))
+        ("read_text_file" ("builtin" "builtinReadTextFile"))
+        ("write_text_file" ("builtin" "builtinWriteTextFile"))
+        ("push" ("builtin" "builtinPush"))
+        ("at" ("builtin" "builtinAt"))
+        ("set" ("builtin" "builtinSet"))
+        ("len" ("builtin" "builtinLen"))
+        ("string_to_int" ("builtin" "builtinStringToInt"))
+        ("char_code" ("builtin" "builtinCharCode"))
+        ("strings_join" ("builtin" "builtinStringsJoin"))
+        ("get_args" ("builtin" "builtinGetArgs"))
+    )))
 
     (fn enter_scope () (do
         (= syms (syms ()))
@@ -455,18 +396,18 @@
     ))
 
     (fn define (ident sym) (do
-        (let (_ map) syms)
+        (let (_ syms) syms)
         (let i 0)
         (loop (do
-            (if (>= i (call len map)) (break))
+            (if (>= i (call len syms)) (break))
-            (let (s_ident _) (call at map i))
+            (let (s_ident _) (call at syms i))
             (if (== ident s_ident) (do
-                (call set map i (ident sym))
+                (call set syms i (ident sym))
                 (return)
             ))
             (+= i 1)
         ))
-        (call push map (ident sym))
+        (call push syms (ident sym))
     ))
 
     (fn find_sym (syms ident) (do
@@ -765,30 +706,25 @@
     (return elems)
 ))
 
-(let silent false)
+(let silent true)
 
 (let (input_filename output_filename) (call get_args))
 
-(if (not silent) (call println "reading file '%'..." input_filename))
+(if (not silent) (call println "reading file..."))
 (let text (call read_text_file input_filename))
 
-//(call println "=== text ===")
+(call println "=== text ===")
 // (call println text)
-//(call println (call len text))
+(call println (call len text))
 
 (if (not silent) (call println "tokenizing..."))
 (let tokens (call tokenize text))
 
-//(call println "=== tokens ===")
+(call println "=== tokens ===")
-//(for elem tokens (do
+// (for (tok line value) tokens (do
-//    (let (tok line value) elem)
+//    (call println "%\t%\t%" line tok (if (!= value null) value ""))
-//    (if (!= value null) (do
-//        (call println "%\t%\t%" line tok value)
-//    ) (do
-//        (call println "%\t%" line tok)
 // ))
-//))
+(call println (call len tokens))
-//(call println (call len tokens))
 
 (if (not silent) (call println "parsing..."))
 (let parser (call Parser tokens))
@@ -808,7 +744,7 @@
 // (call println "=== js ===")
 // (call println js_code)
 
-(if (not silent) (call println "writing file '%'..." output_filename))
+(if (not silent) (call println "writing file..."))
 (call write_text_file output_filename js_code)
 
 

make_stage2.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+set -xe
+
+node stage1.js compile.phi stage2.js

phi.js

@@ -0,0 +1,603 @@
+"use strict";
+
+import fs from "node:fs";
+import process from "node:process";
+import { Runtime } from "./runtime.js";
+
+function main() {
+    const filename = process.argv[2];
+    const text = fs.readFileSync(filename).toString();
+
+    const ast = new Parser(text).parse();
+
+    let lastValue = null;
+
+    const evaluator = new Evaluator(filename);
+    for (const expr of ast) {
+        const result = evaluator.eval(expr);
+        if (result.type !== "value") {
+            break;
+        }
+        lastValue = result.value;
+    }
+    if (lastValue !== null) {
+        // console.log(Runtime.valueToJs(lastValue));
+    }
+}
+
+class Evaluator {
+    constructor(filename) {
+        this.syms = { parent: undefined, map: new Map(this.builtins) };
+        this.currentLine = 0;
+        this.filename = filename;
+        this.runtime = new Runtime({ filename, args: process.argv.slice(3) });
+    }
+
+    /**
+     * @param {Expr} expr
+     */
+    eval(expr) {
+        if (!expr) {
+            this.runtime.printPanic(
+                "expression could not be evaluated",
+                this.currentLine,
+            );
+            throw new Error("expression could not be evaluated");
+        }
+
+        this.currentLine = expr.line;
+        this.runtime.setLine(expr.line)
+        if (expr.type === "list") {
+            return this.evalList(expr, expr.line);
+        } else if (expr.type === "int") {
+            return { type: "value", value: { type: "int", value: expr.value } };
+        } else if (expr.type === "string") {
+            return {
+                type: "value",
+                value: { type: "string", value: expr.value },
+            };
+        } else if (expr.type === "ident") {
+            const sym = this.findSym(expr.value);
+            if (!sym) {
+                this.panic(
+                    `undefined symbol '${expr.value}'`,
+                );
+            }
+            if (sym.type === "local") {
+                return { type: "value", value: { ...sym.value } };
+            } else {
+                return { type: "value", value: { ...sym } };
+            }
+        } else {
+            throw new Error(
+                `unknown expr type '${expr.type}' on line ${expr.line}`,
+            );
+        }
+    }
+
+    evalToValue(expr) {
+        const result = this.eval(expr);
+        if (result.type !== "value") {
+            throw new Error(`expected value on line ${expr.line}`);
+        }
+        return result.value;
+    }
+
+    evalList(expr) {
+        const s = expr.values;
+        const id = s[0]?.type === "ident" ? s[0].value : undefined;
+        if (id === "fn") {
+            return this.evalFn(expr);
+        } else if (id === "return") {
+            return {
+                type: "return",
+                value: s[1] ? this.evalToValue(s[1]) : { type: "null" },
+            };
+        } else if (id === "let") {
+            return this.evalLet(expr);
+        } else if (id === "if") {
+            return this.evalIf(expr);
+        } else if (id === "loop") {
+            return this.evalLoop(expr);
+        } else if (id === "for") {
+            return this.evalFor(expr);
+        } else if (id === "break") {
+            return {
+                type: "break",
+                value: s[1] ? this.evalToValue(s[1]) : { type: "null" },
+            };
+        } else if (id === "do") {
+            return this.evalDo(expr);
+        } else if (id === "call") {
+            return this.evalCall(expr);
+        } else if (id === "not") {
+            const value = this.evalToValue(s[1]);
+            return {
+                type: "value",
+                value: { type: "bool", value: !value.value },
+            };
+        } else if (id === "or") {
+            const left = this.evalToValue(s[1]);
+            if (this.runtime.truthy(left)) {
+                return { type: "value", value: { type: "bool", value: true } };
+            } else {
+                const right = this.evalToValue(s[2]);
+                return { type: "value", value: { type: "bool", value: this.runtime.truthy(right) } };
+            }
+        } else if (id === "and") {
+            const left = this.evalToValue(s[1]);
+            if (this.runtime.truthy(left)) {
+                const right = this.evalToValue(s[2]);
+                return { type: "value", value: { type: "bool", value: this.runtime.truthy(right) } };
+            } else {
+                return { type: "value", value: { type: "bool", value: false } };
+            }
+        } else if (id in this.artithmeticOps) {
+            const left = this.evalToValue(s[1]);
+            const right = this.evalToValue(s[2]);
+            return { type: "value", value: this.artithmeticOps[id](left, right) };
+        } else if (id === "==") {
+            const left = this.evalToValue(s[1]);
+            const right = this.evalToValue(s[2]);
+            return {
+                type: "value",
+                value: this.runtime.opEq(left, right),
+            };
+        } else if (id === "!=") {
+            const left = this.evalToValue(s[1]);
+            const right = this.evalToValue(s[2]);
+            return {
+                type: "value",
+                value: this.runtime.opNe(left, right),
+            };
+        } else if (id in this.comparisonOps) {
+            const left = this.evalToValue(s[1]);
+            const right = this.evalToValue(s[2]);
+            return {
+                type: "value",
+                value: this.runtime.comparisonOperation(left, right, this.comparisonOps[id]),
+            };
+        } else if (id in this.assignOps) {
+            return this.evalAssign(expr);
+        } else {
+            return {
+                type: "value",
+                value: {
+                    type: "list",
+                    values: s.map((expr) => this.evalToValue(expr)),
+                },
+            };
+        }
+    }
+
+    evalFn(expr) {
+        const s = expr.values;
+        const name = s[1].value;
+        this.syms.map.set(name, {
+            type: "fn",
+            line: expr.line,
+            name,
+            params: s[2].values.map((ident) => ident.value),
+            body: s[3],
+            syms: this.syms,
+        });
+        return { type: "value", value: { type: "null" } };
+    }
+
+    evalLet(expr) {
+        const s = expr.values;
+        const value = this.evalToValue(s[2]);
+        this.assignPattern(s[1], value);
+        return { type: "value", value: { type: "null" } };
+    }
+
+    evalIf(expr) {
+        const s = expr.values;
+        const cond = this.evalToValue(s[1]);
+        if (cond.type !== "bool") {
+            throw new Error(
+                `expected bool on line ${expr.line}`,
+            );
+        }
+        if (cond.value) {
+            return this.eval(s[2]);
+        } else if (s[3]) {
+            return this.eval(s[3]);
+        } else {
+            return { type: "value", value: "null" };
+        }
+    }
+
+    evalLoop(expr) {
+        const s = expr.values;
+        while (true) {
+            const result = this.eval(s[1]);
+            if (result.type === "break") {
+                return { type: "value", value: result.value };
+            } else if (result.type !== "value") {
+                return result;
+            }
+        }
+    }
+
+    evalFor(expr) {
+        const s = expr.values;
+
+        const value = this.evalToValue(s[2]);
+        if (value.type !== "list") {
+            throw new Error(
+                `expected list on line ${expr.line}`,
+            );
+        }
+
+        const outerSyms = this.syms;
+        this.syms = { parent: outerSyms, map: new Map() };
+
+        for (let i = 0; i < value.values.length; ++i) {
+            this.assignPattern(s[1], value.values[i]);
+            const result = this.eval(s[3]);
+            if (result.type === "break") {
+                return { type: "value", value: result.value };
+            } else if (result.type !== "value") {
+                return result;
+            }
+        }
+        this.syms = outerSyms;
+        return { type: "value", value: { type: "null" } };
+    }
+
+    evalDo(expr) {
+        const s = expr.values;
+        const outerSyms = this.syms;
+        this.syms = { parent: outerSyms, map: new Map() };
+
+        let lastValue = { type: "null" };
+
+        for (const expr of s.slice(1)) {
+            const result = this.eval(expr);
+            if (result.type !== "value") {
+                return result;
+            }
+            lastValue = result.value;
+        }
+
+        this.syms = outerSyms;
+        return { type: "value", value: lastValue };
+    }
+
+    evalCall(expr) {
+        const s = expr.values;
+        const args = s.slice(2).map((arg) => this.evalToValue(arg));
+        const fnValue = this.evalToValue(s[1]);
+
+        if (fnValue.type === "builtin") {
+            return { type: "value", value: fnValue.fn(...args) };
+        } else if (fnValue.type !== "fn") {
+            throw new Error("cannot call non-function");
+        }
+
+        this.runtime.pushCall(fnValue.name, expr.line);
+        const callerSyms = this.syms;
+        this.syms = {
+            parent: fnValue.syms,
+            map: new Map(),
+        };
+        if (fnValue.params.length !== args.length) {
+            this.panic(
+                `incorrect amount of arguments for function '${fnValue.name}'`,
+            );
+        }
+        for (let i = 0; i < fnValue.params.length; ++i) {
+            this.syms.map.set(fnValue.params[i], args[i]);
+        }
+
+        let returnValue = { type: "null" };
+        const result = this.eval(fnValue.body);
+
+        if (result.type === "value" || result.type === "return") {
+            returnValue = result.value;
+        } else {
+            throw new Error(`illegal ${result.type} across boundry`);
+        }
+
+        this.syms = callerSyms;
+        this.runtime.popCall();
+        return { type: "value", value: returnValue };
+    }
+
+    evalAssign(expr) {
+        const s = expr.values;
+        const id = s[0].value;
+        if (s[1].type === "ident") {
+            const sym = this.findSym(s[1].value);
+            if (!sym) {
+                throw new Error(
+                    `could not find symbol '${expr.value}' on line ${expr.line}`,
+                );
+            }
+            const value = this.evalToValue(s[2]);
+            if (sym.type === "local") {
+                sym.value = this.assignOps[id](sym.value, value);
+            } else {
+                throw new Error(
+                    `cannot assign to symbol on line ${expr.line}`,
+                );
+            }
+        } else {
+            throw new Error(
+                `cannot assign to expression on line ${expr.line}`,
+            );
+        }
+        return { type: "value", value: { type: "null" } };
+    }
+
+    /** @param {Expr} pattern */
+    assignPattern(pattern, value) {
+        if (pattern.type === "ident") {
+            if (pattern.value === "_") {
+                return;
+            }
+            this.syms.map.set(pattern.value, {
+                type: "local",
+                line: pattern.line,
+                value,
+            });
+        } else if (pattern.type === "list") {
+            if (value.type !== "list") {
+                this.panic(`expected list`);
+            }
+            for (const [i, p] of pattern.values.entries()) {
+                this.assignPattern(p, value.values[i] ?? { type: "null" });
+            }
+        } else {
+            throw new Error(`cannot assign to pattern on line ${pattern.line}`);
+        }
+    }
+
+    findSym(ident, syms = this.syms) {
+        if (syms.map.has(ident)) {
+            return syms.map.get(ident);
+        } else if (syms.parent) {
+            return this.findSym(ident, syms.parent);
+        } else {
+            return undefined;
+        }
+    }
+
+    panic(msg) {
+        this.runtime.setLine(this.currentLine);
+        this.runtime.panic(msg);
+    }
+
+    artithmeticOps = {
+        "+": (left, right) => this.runtime.opAdd(left, right),
+        "-": (left, right) => this.runtime.opSub(left, right),
+    };
+    comparisonOps = {
+        "<": (left, right) => left < right,
+        ">": (left, right) => left > right,
+        "<=": (left, right) => left <= right,
+        ">=": (left, right) => left >= right,
+    };
+    assignOps = {
+        "=": (_, right) => right,
+        "+=": (left, right) => ({
+            type: left.type === "string" && left.type === right.type
+                ? "string"
+                : "int",
+            value: left.value + right.value,
+        }),
+        "-=": (left, right) => ({
+            type: "int",
+            value: left.value - right.value,
+        }),
+    };
+
+    builtinFns = {
+        "format": (...args) => this.runtime.builtinFormat(...args),
+        "print": (...args) => this.runtime.builtinPrint(...args),
+        "println": (...args) => this.runtime.builtinPrintln(...args),
+        "panic": (...args) => this.runtime.builtinPanic(...args),
+        "read_text_file": (...args) => this.runtime.builtinReadTextFile(...args),
+        "write_text_file": (...args) => this.runtime.builtinWriteTextFile(...args),
+        "push": (...args) => this.runtime.builtinPush(...args),
+        "at": (...args) => this.runtime.builtinAt(...args),
+        "set": (...args) => this.runtime.builtinSet(...args),
+        "len": (...args) => this.runtime.builtinLen(...args),
+        "string_to_int": (...args) => this.runtime.builtinStringToInt(...args),
+        "char_code": (...args) => this.runtime.builtinCharCode(...args),
+        "strings_join": (...args) => this.runtime.builtinStringsJoin(...args),
+        "get_args": (...args) => this.runtime.builtinGetArgs(...args),
+    };
+
+    consts = {
+        "null": { type: "null" },
+        "false": { type: "bool", value: false },
+        "true": { type: "bool", value: true },
+    };
+
+    builtins = [
+        ...Object.entries(this.builtinFns)
+            .map(([key, fn]) => [key, { type: "builtin", fn }]),
+        ...Object.entries(this.consts),
+    ];
+}
+
+/**
+ * @param {Expr} expr
+ * @returns {string}
+ */
+function exprToString(expr) {
+    if (expr.type === "ident") {
+        return expr.value;
+    } else if (expr.type === "int") {
+        return `${expr.value}`;
+    } else if (expr.type === "string") {
+        return `"${expr.value}"`;
+    } else if (expr.type === "list") {
+        return `(${expr.values.map((v) => exprToString(v)).join(" ")})`;
+    } else {
+        throw new Error(`unknown value type ${expr.type}`);
+    }
+}
+
+/**
+ * @typedef {{ type: string, line: number, value: any, values?: Expr } } Expr
+ */
+
+class Parser {
+    constructor(text) {
+        const stringExtractor = new StringExtractor(text);
+        stringExtractor.extract();
+        this.strings = stringExtractor.getStrings();
+        this.text = stringExtractor.getOutputText();
+        this.tokens = this.text
+            .replace(/\/\/.*?$/mg, "")
+            .replace(/([\(\)\n])/g, " $1 ")
+            .split(/[ \t\r]/)
+            .filter((tok) => tok !== "");
+        this.idx = 0;
+        this.line = 1;
+    }
+
+    /**
+     * @returns {Expr[]}
+     */
+    parse() {
+        if (this.curr === "\n") {
+            this.step();
+        }
+
+        const exprs = [];
+        while (!this.done) {
+            exprs.push(this.parseExpr());
+        }
+        return exprs;
+    }
+
+    parseExpr() {
+        const line = this.line;
+        if (this.eat("(")) {
+            const values = [];
+            while (!this.test(")")) {
+                values.push(this.parseExpr());
+            }
+            if (!this.test(")")) {
+                throw new Error(`expected ')'`);
+            }
+            this.step();
+            return { type: "list", line, values };
+        } else if (this.test(/STRING_\d+/)) {
+            const id = Number(this.curr.match(/STRING_(\d+)/)[1]);
+            this.step();
+            return { type: "string", line, value: this.strings[id] };
+        } else if (this.test(/0|(:?[1-9][0-9]*)/)) {
+            const value = Number(this.curr);
+            this.step();
+            return { type: "int", line, value };
+        } else if (this.test(/[a-zA-Z0-9\+\-\*/%&\|=\?\!<>'_]+/)) {
+            const value = this.curr;
+            this.step();
+            return { type: "ident", line, value };
+        } else {
+            throw new Error(
+                `expected expression, got ${this.curr} on line ${this.line}`,
+            );
+        }
+    }
+
+    eat(tok) {
+        if (!this.test(tok)) {
+            return false;
+        }
+        this.step();
+        return true;
+    }
+    test(tok) {
+        if (this.done) {
+            return false;
+        }
+        if (typeof tok === "string") {
+            return this.curr === tok;
+        } else if (tok instanceof RegExp) {
+            return new RegExp(`^${tok.source}$`)
+                .test(this.curr);
+        } else {
+            throw new Error();
+        }
+    }
+    step() {
+        do {
+            if (!this.done && this.curr === "\n") {
+                this.line += 1;
+            }
+            this.idx += 1;
+        } while (!this.done && this.curr === "\n");
+    }
+
+    get done() {
+        return this.idx >= this.tokens.length;
+    }
+    get curr() {
+        return this.tokens[this.idx];
+    }
+}
+
+class StringExtractor {
+    constructor(text) {
+        this.text = text;
+        this.idx = 0;
+        this.outputText = "";
+        this.strings = [];
+    }
+
+    extract() {
+        while (this.idx < this.text.length) {
+            if (this.text[this.idx] == '"') {
+                this.extractString();
+            } else {
+                this.outputText += this.text[this.idx];
+                this.idx += 1;
+            }
+        }
+    }
+
+    extractString() {
+        this.idx += 1;
+        let value = "";
+        while (this.idx < this.text.length && this.text[this.idx] != '"') {
+            if (this.text[this.idx] == "\\") {
+                this.idx += 1;
+                if (this.idx > this.text.length) {
+                    break;
+                }
+                const ch = this.text[this.idx];
+                value += {
+                    "0": "\0",
+                    "t": "\t",
+                    "r": "\r",
+                    "n": "\n",
+                }[ch] ?? ch;
+            } else {
+                value += this.text[this.idx];
+            }
+            this.idx += 1;
+        }
+        if (this.idx >= this.text.length || this.text[this.idx] != '"') {
+            throw new Error("expected '\"'");
+        }
+        this.idx += 1;
+        const id = this.strings.length;
+        this.strings.push(value);
+        this.outputText += `STRING_${id}`;
+    }
+
+    getStrings() {
+        return this.strings;
+    }
+    getOutputText() {
+        return this.outputText;
+    }
+}
+
+main();

runtime.js

@@ -84,11 +84,11 @@ export class Runtime {
     }
 
     opEq(left, right) {
-        return { type: "bool", value: this.equalityOperation(left, right) };
+        return { type: "bool", value: this.equalityOperation(left, right) }
     }
 
     opNe(left, right) {
-        return { type: "bool", value: !this.equalityOperation(left, right) };
+        return { type: "bool", value: !this.equalityOperation(left, right) }
     }
 
     opNot(expr) {
@@ -105,31 +105,23 @@ export class Runtime {
         return { type: "bool", value: action(left.value, right.value) };
     }
 
-    opLt(left, right) {
+    opLt(left, right) { return this.comparisonOperation(right, left, (l, r) => l < r); }
-        return this.comparisonOperation(left, right, (l, r) => l < r);
+    opGt(left, right) { return this.comparisonOperation(right, left, (l, r) => l > r); }
-    }
+    opLte(left, right) { return this.comparisonOperation(right, left, (l, r) => l <= r); }
-    opGt(left, right) {
+    opGte(left, right) { return this.comparisonOperation(right, left, (l, r) => l >= r); }
-        return this.comparisonOperation(left, right, (l, r) => l > r);
-    }
-    opLte(left, right) {
-        return this.comparisonOperation(left, right, (l, r) => l <= r);
-    }
-    opGte(left, right) {
-        return this.comparisonOperation(left, right, (l, r) => l >= r);
-    }
 
     opAdd(left, right) {
         if (left.type === "int" && right.type === "int") {
-            return { type: "int", value: left.value + right.value };
+            return { type: "int", value: left.value + right.value }
         } else if (left.type === "string" && right.type === "string") {
-            return { type: "string", value: left.value + right.value };
+            return { type: "string", value: left.value + right.value }
         } else {
             this.panic(`cannot apply '+' on ${left.type} and ${right.type}`);
         }
     }
     opSub(left, right) {
         if (left.type === "int" && right.type === "int") {
-            return { type: "int", value: left.value - right.value };
+            return { type: "int", value: left.value + right.value }
         } else {
             this.panic(`cannot apply '-' on ${left.type} and ${right.type}`);
         }
@@ -234,8 +226,7 @@ export class Runtime {
         } else if (value.type === "string") {
             return `${value.value}`;
         } else if (value.type === "list") {
-            return `(${
+            return `(${value.values.map((v) => Runtime.valueToString(v)).join(" ")
-                value.values.map((v) => Runtime.valueToString(v)).join(" ")
                 })`;
         } else {
             throw new Error(`unknown value type ${value.type}`);
@@ -252,8 +243,7 @@ export class Runtime {
         } else if (value.type === "string") {
             return `"${value.value}"`;
         } else if (value.type === "list") {
-            return `(${
+            return `(${value.values.map((v) => Runtime.valueToString(v)).join(" ")
-                value.values.map((v) => Runtime.valueToString(v)).join(" ")
                 })`;
         } else {
             throw new Error(`unknown value type ${value.type}`);