From 9f3de1edf6253e9bf6a919d149ef6485e1e31d10 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Mon, 30 Mar 2026 20:00:00 +0200
Subject: [PATCH] Add an interpreter for optimized ps code

It'll be used as a fallback when wasm is disabled.
And add in the debugger a view for the generated js code and one for the ps code.
---
 src/core/document.js                 |  16 +
 src/core/function.js                 |  14 +-
 src/core/internal_viewer_utils.js    | 387 +++++++++++++++++++
 src/core/postscript/ast.js           |   2 +-
 src/core/postscript/js_evaluator.js  | 550 +++++++++++++++++++++++++++
 src/core/postscript/wasm_compiler.js |  16 +-
 test/unit/postscript_spec.js         | 266 +++++--------
 web/internal/multiline_view.css      |   1 +
 web/internal/tree_view.css           |   1 +
 web/internal/tree_view.js            | 140 +++++++
 10 files changed, 1217 insertions(+), 176 deletions(-)
 create mode 100644 src/core/postscript/js_evaluator.js

diff --git a/src/core/document.js b/src/core/document.js
index 5777c998e..f91a9f29b 100644
--- a/src/core/document.js
+++ b/src/core/document.js
@@ -2136,6 +2136,22 @@ class PDFDocument {
         return obj;
       }
 
+      if (dict.get("FunctionType") === 4) {
+        const source = value.getString();
+        value.reset();
+        const domain = dict.get("Domain") ?? [];
+        const range = dict.get("Range") ?? [];
+        obj.psFunction = true;
+        obj.source = source;
+        obj.psLines = InternalViewerUtils.tokenizePSSource(source);
+        obj.jsCode = InternalViewerUtils.postScriptToJSCode(
+          source,
+          domain,
+          range
+        );
+        return obj;
+      }
+
       obj.bytes = value.getString();
       return obj;
     }
diff --git a/src/core/function.js b/src/core/function.js
index b00e60670..2bfa150d6 100644
--- a/src/core/function.js
+++ b/src/core/function.js
@@ -25,6 +25,7 @@ import {
 } from "../shared/util.js";
 import { PostScriptLexer, PostScriptParser } from "./ps_parser.js";
 import { BaseStream } from "./base_stream.js";
+import { buildPostScriptJsFunction } from "./postscript/js_evaluator.js";
 import { buildPostScriptWasmFunction } from "./postscript/wasm_compiler.js";
 import { isNumberArray } from "./core_utils.js";
 import { LocalFunctionCache } from "./image_utils.js";
@@ -370,8 +371,8 @@ class PDFFunction {
       throw new FormatError("No range.");
     }
 
-    if (factory.useWasm) {
-      try {
+    try {
+      if (factory.useWasm) {
         const wasmFn = buildPostScriptWasmFunction(
           fn.getString(),
           domain,
@@ -380,9 +381,14 @@ class PDFFunction {
         if (wasmFn) {
           return wasmFn; // (src, srcOffset, dest, destOffset) → void
         }
-      } catch {
-        // Fall through to the existing interpreter-based path.
+      } else {
+        const jsFn = buildPostScriptJsFunction(fn.getString(), domain, range);
+        if (jsFn) {
+          return jsFn; // (src, srcOffset, dest, destOffset) → void
+        }
       }
+    } catch {
+      // Fall through to the existing interpreter-based path.
     }
 
     warn("Unable to compile PS function, using interpreter");
diff --git a/src/core/internal_viewer_utils.js b/src/core/internal_viewer_utils.js
index 0b5cd4cef..dcb48db7a 100644
--- a/src/core/internal_viewer_utils.js
+++ b/src/core/internal_viewer_utils.js
@@ -16,6 +16,13 @@
 import { Cmd, Dict, EOF, Name, Ref } from "./primitives.js";
 import { Lexer, Parser } from "./parser.js";
 import { OPS, shadow } from "../shared/util.js";
+import {
+  parsePostScriptFunction,
+  PS_NODE,
+  PS_VALUE_TYPE,
+  PSStackToTree,
+} from "./postscript/ast.js";
+import { Lexer as PsLexer, TOKEN } from "./postscript/lexer.js";
 import { BaseStream } from "./base_stream.js";
 import { EvaluatorPreprocessor } from "./evaluator.js";
 
@@ -26,6 +33,262 @@ if (
   throw new Error("Not implemented: InternalViewerUtils");
 }
 
+// JS operator precedence levels.
+const PREC = {
+  ATOM: 100, // literals, identifiers, calls — never need parens
+  UNARY: 14,
+  POW: 13, // right-associative
+  MUL: 12,
+  ADD: 11,
+  SHIFT: 10,
+  CMP: 9,
+  EQ: 8,
+  BAND: 7,
+  BXOR: 6,
+  BOR: 5,
+  TERNARY: 3,
+};
+
+// Wrap left (or commutative) operand when child prec < op prec.
+function _wrapLeft(child, opPrec) {
+  return child.prec < opPrec ? `(${child.expr})` : child.expr;
+}
+
+// Wrap right operand (or left of **) when child prec <= op prec.
+function _wrapRight(child, opPrec) {
+  return child.prec <= opPrec ? `(${child.expr})` : child.expr;
+}
+
+function _nodeToExpr(node, argNames, cseMap) {
+  if (cseMap?.has(node)) {
+    return { expr: cseMap.get(node), prec: PREC.ATOM };
+  }
+  switch (node.type) {
+    case PS_NODE.arg:
+      return { expr: argNames[node.index], prec: PREC.ATOM };
+    case PS_NODE.const: {
+      const v = node.value;
+      return {
+        expr: String(typeof v === "boolean" ? Number(v) : v),
+        prec: PREC.ATOM,
+      };
+    }
+    case PS_NODE.unary:
+      return _unaryToExpr(node, argNames, cseMap);
+    case PS_NODE.binary:
+      return _binaryToExpr(node, argNames, cseMap);
+    case PS_NODE.ternary:
+      return _ternaryToExpr(node, argNames, cseMap);
+    default:
+      return null;
+  }
+}
+
+function _unaryToExpr(node, argNames, cseMap) {
+  const { op, operand, valueType } = node;
+  if (op === TOKEN.cvr) {
+    return _nodeToExpr(operand, argNames, cseMap);
+  }
+  const x = _nodeToExpr(operand, argNames, cseMap);
+  if (x === null) {
+    return null;
+  }
+  switch (op) {
+    case TOKEN.abs:
+      return { expr: `Math.abs(${x.expr})`, prec: PREC.ATOM };
+    case TOKEN.neg:
+      return { expr: `-${_wrapLeft(x, PREC.UNARY)}`, prec: PREC.UNARY };
+    case TOKEN.ceiling:
+      return { expr: `Math.ceil(${x.expr})`, prec: PREC.ATOM };
+    case TOKEN.floor:
+      return { expr: `Math.floor(${x.expr})`, prec: PREC.ATOM };
+    case TOKEN.round:
+      return {
+        expr: `Math.floor(${_wrapLeft(x, PREC.ADD)} + 0.5)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.truncate:
+      return { expr: `Math.trunc(${x.expr})`, prec: PREC.ATOM };
+    case TOKEN.sqrt:
+      return { expr: `Math.sqrt(${x.expr})`, prec: PREC.ATOM };
+    case TOKEN.sin:
+      return {
+        expr: `Math.sin(${_wrapLeft(x, PREC.MUL)} % 360 * (Math.PI / 180))`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.cos:
+      return {
+        expr: `Math.cos(${_wrapLeft(x, PREC.MUL)} % 360 * (Math.PI / 180))`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.ln:
+      return { expr: `Math.log(${x.expr})`, prec: PREC.ATOM };
+    case TOKEN.log:
+      return { expr: `Math.log10(${x.expr})`, prec: PREC.ATOM };
+    case TOKEN.cvi:
+      return { expr: `(Math.trunc(${x.expr}) | 0)`, prec: PREC.ATOM };
+    case TOKEN.not:
+      if (valueType === PS_VALUE_TYPE.boolean) {
+        return {
+          expr: `(${_wrapLeft(x, PREC.EQ)} === 0 ? 1 : 0)`,
+          prec: PREC.ATOM,
+        };
+      }
+      if (valueType === PS_VALUE_TYPE.numeric) {
+        return {
+          expr: `~(${_wrapLeft(x, PREC.BOR)} | 0)`,
+          prec: PREC.UNARY,
+        };
+      }
+      return null;
+    default:
+      return null;
+  }
+}
+
+function _binaryToExpr(node, argNames, cseMap) {
+  const { op, first, second } = node;
+  if (op === TOKEN.bitshift) {
+    if (first.type !== PS_NODE.const || !Number.isInteger(first.value)) {
+      return null;
+    }
+    const s = _nodeToExpr(second, argNames, cseMap);
+    if (s === null) {
+      return null;
+    }
+    const amt = first.value;
+    const base = `(${_wrapLeft(s, PREC.BOR)} | 0)`;
+    if (amt > 0) {
+      return { expr: `${base} << ${amt}`, prec: PREC.SHIFT };
+    }
+    if (amt < 0) {
+      return { expr: `${base} >> ${-amt}`, prec: PREC.SHIFT };
+    }
+    return { expr: base, prec: PREC.ATOM };
+  }
+  // second is left operand (below on stack), first is right (top).
+  const a = _nodeToExpr(second, argNames, cseMap);
+  const b = _nodeToExpr(first, argNames, cseMap);
+  if (a === null || b === null) {
+    return null;
+  }
+  switch (op) {
+    case TOKEN.add:
+      return {
+        expr: `${_wrapLeft(a, PREC.ADD)} + ${_wrapLeft(b, PREC.ADD)}`,
+        prec: PREC.ADD,
+      };
+    case TOKEN.sub:
+      return {
+        expr: `${_wrapLeft(a, PREC.ADD)} - ${_wrapRight(b, PREC.ADD)}`,
+        prec: PREC.ADD,
+      };
+    case TOKEN.mul:
+      return {
+        expr: `${_wrapLeft(a, PREC.MUL)} * ${_wrapLeft(b, PREC.MUL)}`,
+        prec: PREC.MUL,
+      };
+    case TOKEN.div:
+      return {
+        expr:
+          `(${b.expr} !== 0 ? ` +
+          `${_wrapLeft(a, PREC.MUL)} / ${_wrapRight(b, PREC.MUL)} : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.idiv:
+      return {
+        expr:
+          `(${b.expr} !== 0 ? ` +
+          `Math.trunc(${_wrapLeft(a, PREC.MUL)} / ${_wrapRight(b, PREC.MUL)}) : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.mod:
+      return {
+        expr:
+          `(${b.expr} !== 0 ? ` +
+          `${_wrapLeft(a, PREC.MUL)} % ${_wrapRight(b, PREC.MUL)} : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.exp:
+      return {
+        expr: `${_wrapRight(a, PREC.POW)} ** ${_wrapLeft(b, PREC.POW)}`,
+        prec: PREC.POW,
+      };
+    case TOKEN.eq:
+      return {
+        expr: `(${_wrapLeft(a, PREC.CMP)} === ${_wrapLeft(b, PREC.CMP)} ? 1 : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.ne:
+      return {
+        expr: `(${_wrapLeft(a, PREC.CMP)} !== ${_wrapLeft(b, PREC.CMP)} ? 1 : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.gt:
+      return {
+        expr: `(${_wrapLeft(a, PREC.CMP)} > ${_wrapLeft(b, PREC.CMP)} ? 1 : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.ge:
+      return {
+        expr: `(${_wrapLeft(a, PREC.CMP)} >= ${_wrapLeft(b, PREC.CMP)} ? 1 : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.lt:
+      return {
+        expr: `(${_wrapLeft(a, PREC.CMP)} < ${_wrapLeft(b, PREC.CMP)} ? 1 : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.le:
+      return {
+        expr: `(${_wrapLeft(a, PREC.CMP)} <= ${_wrapLeft(b, PREC.CMP)} ? 1 : 0)`,
+        prec: PREC.ATOM,
+      };
+    case TOKEN.and:
+      return {
+        expr: `(${_wrapLeft(a, PREC.BOR)} | 0) & (${_wrapLeft(b, PREC.BOR)} | 0)`,
+        prec: PREC.BAND,
+      };
+    case TOKEN.or:
+      return {
+        expr: `(${_wrapLeft(a, PREC.BOR)} | 0) | (${_wrapLeft(b, PREC.BOR)} | 0)`,
+        prec: PREC.BOR,
+      };
+    case TOKEN.xor:
+      return {
+        expr: `(${_wrapLeft(a, PREC.BOR)} | 0) ^ (${_wrapLeft(b, PREC.BOR)} | 0)`,
+        prec: PREC.BXOR,
+      };
+    case TOKEN.atan:
+      // atan2 result in degrees [0, 360).
+      return {
+        expr: `(Math.atan2(${a.expr}, ${b.expr}) * (180 / Math.PI) + 360) % 360`,
+        prec: PREC.MUL,
+      };
+    case TOKEN.min:
+      return { expr: `Math.min(${a.expr}, ${b.expr})`, prec: PREC.ATOM };
+    case TOKEN.max:
+      return { expr: `Math.max(${a.expr}, ${b.expr})`, prec: PREC.ATOM };
+    default:
+      return null;
+  }
+}
+
+function _ternaryToExpr(node, argNames, cseMap) {
+  const cond = _nodeToExpr(node.cond, argNames, cseMap);
+  const then = _nodeToExpr(node.then, argNames, cseMap);
+  const otherwise = _nodeToExpr(node.otherwise, argNames, cseMap);
+  if (cond === null || then === null || otherwise === null) {
+    return null;
+  }
+  return {
+    expr:
+      `(${_wrapLeft(cond, PREC.EQ)} !== 0 ? ` +
+      `${_wrapLeft(then, PREC.TERNARY)} : ${_wrapLeft(otherwise, PREC.TERNARY)})`,
+    prec: PREC.ATOM,
+  };
+}
+
 const InternalViewerUtils = {
   tokenizeStream(stream, xref) {
     const tokens = [];
@@ -125,6 +388,130 @@ const InternalViewerUtils = {
     return { instructions, cmdNames };
   },
 
+  // Tokenize a PS Type 4 source into display lines: each line groups args with
+  // the operator that consumes them; braces get their own indented lines.
+  tokenizePSSource(source) {
+    const lexer = new PsLexer(source);
+    const lines = [];
+    let indent = 0;
+    let buffer = [];
+
+    const flush = () => {
+      if (buffer.length > 0) {
+        lines.push({ indent, tokens: buffer });
+        buffer = [];
+      }
+    };
+
+    while (true) {
+      const tok = lexer.next();
+      if (tok.id === TOKEN.eof) {
+        break;
+      }
+      if (tok.id === TOKEN.lbrace) {
+        flush();
+        lines.push({ indent, tokens: [{ type: "brace", value: "{" }] });
+        indent++;
+      } else if (tok.id === TOKEN.rbrace) {
+        flush();
+        indent = Math.max(0, indent - 1);
+        lines.push({ indent, tokens: [{ type: "brace", value: "}" }] });
+      } else if (tok.id === TOKEN.number) {
+        buffer.push({ type: "number", value: tok.value });
+      } else if (tok.id === TOKEN.true) {
+        buffer.push({ type: "boolean", value: true });
+      } else if (tok.id === TOKEN.false) {
+        buffer.push({ type: "boolean", value: false });
+      } else if (tok.value !== null) {
+        buffer.push({ type: "cmd", value: tok.value });
+        flush();
+      }
+    }
+    flush();
+    return lines;
+  },
+
+  postScriptToJSCode(source, domain, range) {
+    const program = parsePostScriptFunction(source);
+    const nIn = domain.length >> 1;
+    const nOut = range.length >> 1;
+    const outputs = new PSStackToTree().evaluate(program, nIn);
+    if (!outputs || outputs.length < nOut) {
+      return null;
+    }
+
+    // Named input variables: single input → "x", multiple → "x0", "x1", …
+    const argNames =
+      nIn === 1 ? ["x"] : Array.from({ length: nIn }, (_, i) => `x${i}`);
+
+    // Build cseMap in topological order using shared marks from the AST.
+    const cseMap = new Map();
+    const tmpDecls = [];
+    let tmpIdx = 0;
+    const visited = new Set();
+    const ensureShared = node => {
+      if (
+        !node ||
+        node.type === PS_NODE.arg ||
+        node.type === PS_NODE.const ||
+        visited.has(node)
+      ) {
+        return;
+      }
+      visited.add(node);
+      switch (node.type) {
+        case PS_NODE.unary:
+          ensureShared(node.operand);
+          break;
+        case PS_NODE.binary:
+          ensureShared(node.first);
+          ensureShared(node.second);
+          break;
+        case PS_NODE.ternary:
+          ensureShared(node.cond);
+          ensureShared(node.then);
+          ensureShared(node.otherwise);
+          break;
+      }
+      if (node.shared) {
+        const result = _nodeToExpr(node, argNames, cseMap);
+        if (result !== null) {
+          const name = `t${tmpIdx++}`;
+          cseMap.set(node, name);
+          tmpDecls.push(`  const ${name} = ${result.expr};`);
+        }
+      }
+    };
+    for (let i = 0; i < nOut; i++) {
+      ensureShared(outputs[i]);
+    }
+
+    const decls = argNames.map(
+      (name, i) => `  const ${name} = src[srcOffset + ${i}];`
+    );
+
+    const assignments = [];
+    for (let i = 0; i < nOut; i++) {
+      const result = _nodeToExpr(outputs[i], argNames, cseMap);
+      if (result === null) {
+        return null;
+      }
+      const min = range[i * 2];
+      const max = range[i * 2 + 1];
+      assignments.push(
+        `  dest[destOffset + ${i}] = ` +
+          `Math.max(Math.min(${result.expr}, ${max}), ${min});`
+      );
+    }
+
+    const lines = [...decls, ""];
+    if (tmpDecls.length > 0) {
+      lines.push(...tmpDecls, "");
+    }
+    lines.push(...assignments);
+    return `(src, srcOffset, dest, destOffset) => {\n${lines.join("\n")}\n}`;
+  },
+
   tokenToJSObject(obj) {
     if (obj instanceof Cmd) {
       return { type: "cmd", value: obj.cmd };
diff --git a/src/core/postscript/ast.js b/src/core/postscript/ast.js
index 086005d5d..9bff1d4db 100644
--- a/src/core/postscript/ast.js
+++ b/src/core/postscript/ast.js
@@ -664,7 +664,7 @@ class PSStackToTree {
     for (const [node, count] of refCount) {
       if (count > 1) {
         node.shared = true;
-        node.sharedCount = count; // remaining-use tracking in backends
+        node.sharedCount = count;
       }
     }
   }
diff --git a/src/core/postscript/js_evaluator.js b/src/core/postscript/js_evaluator.js
new file mode 100644
index 000000000..8bcd77c20
--- /dev/null
+++ b/src/core/postscript/js_evaluator.js
@@ -0,0 +1,550 @@
+/* Copyright 2026 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  parsePostScriptFunction,
+  PS_NODE,
+  PS_VALUE_TYPE,
+  PSStackToTree,
+} from "./ast.js";
+import { TOKEN } from "./lexer.js";
+
+// Consecutive integers for a dense jump table in _execute.
+// 2-slot: ARG, CONST, IF, JUMP, SHIFT. 4-slot: STORE. All others: 1 slot.
+const OP = {
+  ARG: 0, // [ARG, idx]
+  CONST: 1, // [CONST, val]
+  STORE: 2, // [STORE, slot, min, max]  clamp(pop()) → mem[slot]
+  IF: 3, // [IF, target]  jump when top-of-stack === 0
+  JUMP: 4, // [JUMP, target]  unconditional
+  ABS: 5,
+  NEG: 6,
+  CEIL: 7,
+  FLOOR: 8,
+  ROUND: 9, // floor(x + 0.5)
+  TRUNC: 10,
+  NOT_B: 11, // boolean NOT
+  NOT_N: 12, // bitwise NOT
+  SQRT: 13,
+  SIN: 14, // degrees in/out
+  COS: 15,
+  LN: 16,
+  LOG10: 17,
+  CVI: 18,
+  SHIFT: 19, // [SHIFT, amount]  +ve = left, −ve = right
+  // Binary ops: second below, first on top; result = second OP first.
+  ADD: 20,
+  SUB: 21,
+  MUL: 22,
+  DIV: 23, // 0 when divisor is 0
+  IDIV: 24, // 0 when divisor is 0
+  MOD: 25, // 0 when divisor is 0
+  POW: 26,
+  EQ: 27,
+  NE: 28,
+  GT: 29,
+  GE: 30,
+  LT: 31,
+  LE: 32,
+  AND: 33,
+  OR: 34,
+  XOR: 35,
+  ATAN: 36, // atan2(second, first) → degrees [0, 360)
+  MIN: 37,
+  MAX: 38,
+  TEE_TMP: 39, // [TEE_TMP, slot]  peek top of stack → tmp[slot], leave on stack
+  LOAD_TMP: 40, // [LOAD_TMP, slot]  push tmp[slot]
+};
+
+const _DEG_TO_RAD = Math.PI / 180;
+const _RAD_TO_DEG = 180 / Math.PI;
+
+class PsJsCompiler {
+  // Safe because JS is single-threaded.
+  static #stack = new Float64Array(64);
+
+  static #tmp = new Float64Array(64);
+
+  constructor(domain, range) {
+    this.nIn = domain.length >> 1;
+    this.nOut = range.length >> 1;
+    this.range = range;
+    this.ir = [];
+    this._tmpMap = new Map(); // node → tmp slot index (CSE)
+    this._nextTmp = 0;
+  }
+
+  _compileNode(node) {
+    if (node.shared) {
+      const cached = this._tmpMap.get(node);
+      if (cached !== undefined) {
+        this.ir.push(OP.LOAD_TMP, cached);
+        return true;
+      }
+      if (!this._compileNodeImpl(node)) {
+        return false;
+      }
+      const slot = this._nextTmp++;
+      this._tmpMap.set(node, slot);
+      this.ir.push(OP.TEE_TMP, slot);
+      return true;
+    }
+    return this._compileNodeImpl(node);
+  }
+
+  _compileNodeImpl(node) {
+    switch (node.type) {
+      case PS_NODE.arg:
+        this.ir.push(OP.ARG, node.index);
+        return true;
+
+      case PS_NODE.const: {
+        const v = node.value;
+        this.ir.push(OP.CONST, typeof v === "boolean" ? Number(v) : v);
+        return true;
+      }
+
+      case PS_NODE.unary:
+        return this._compileUnary(node);
+
+      case PS_NODE.binary:
+        return this._compileBinary(node);
+
+      case PS_NODE.ternary:
+        return this._compileTernary(node);
+
+      default:
+        return false;
+    }
+  }
+
+  _compileUnary(node) {
+    const { op, operand, valueType } = node;
+
+    // cvr is a no-op — values are already f64.
+    if (op === TOKEN.cvr) {
+      return this._compileNode(operand);
+    }
+
+    if (!this._compileNode(operand)) {
+      return false;
+    }
+
+    switch (op) {
+      case TOKEN.abs:
+        this.ir.push(OP.ABS);
+        break;
+      case TOKEN.neg:
+        this.ir.push(OP.NEG);
+        break;
+      case TOKEN.ceiling:
+        this.ir.push(OP.CEIL);
+        break;
+      case TOKEN.floor:
+        this.ir.push(OP.FLOOR);
+        break;
+      case TOKEN.round:
+        this.ir.push(OP.ROUND);
+        break;
+      case TOKEN.truncate:
+        this.ir.push(OP.TRUNC);
+        break;
+      case TOKEN.sqrt:
+        this.ir.push(OP.SQRT);
+        break;
+      case TOKEN.sin:
+        this.ir.push(OP.SIN);
+        break;
+      case TOKEN.cos:
+        this.ir.push(OP.COS);
+        break;
+      case TOKEN.ln:
+        this.ir.push(OP.LN);
+        break;
+      case TOKEN.log:
+        this.ir.push(OP.LOG10);
+        break;
+      case TOKEN.cvi:
+        this.ir.push(OP.CVI);
+        break;
+      case TOKEN.not:
+        if (valueType === PS_VALUE_TYPE.boolean) {
+          this.ir.push(OP.NOT_B);
+        } else if (valueType === PS_VALUE_TYPE.numeric) {
+          this.ir.push(OP.NOT_N);
+        } else {
+          return false;
+        }
+        break;
+      default:
+        return false;
+    }
+    return true;
+  }
+
+  _compileBinary(node) {
+    const { op, first, second } = node;
+
+    // bitshift requires a constant shift amount.
+    if (op === TOKEN.bitshift) {
+      if (first.type !== PS_NODE.const || !Number.isInteger(first.value)) {
+        return false;
+      }
+      if (!this._compileNode(second)) {
+        return false;
+      }
+      this.ir.push(OP.SHIFT, first.value);
+      return true;
+    }
+
+    if (!this._compileNode(second)) {
+      return false;
+    }
+    if (!this._compileNode(first)) {
+      return false;
+    }
+
+    switch (op) {
+      case TOKEN.add:
+        this.ir.push(OP.ADD);
+        break;
+      case TOKEN.sub:
+        this.ir.push(OP.SUB);
+        break;
+      case TOKEN.mul:
+        this.ir.push(OP.MUL);
+        break;
+      case TOKEN.div:
+        this.ir.push(OP.DIV);
+        break;
+      case TOKEN.idiv:
+        this.ir.push(OP.IDIV);
+        break;
+      case TOKEN.mod:
+        this.ir.push(OP.MOD);
+        break;
+      case TOKEN.exp:
+        this.ir.push(OP.POW);
+        break;
+      case TOKEN.eq:
+        this.ir.push(OP.EQ);
+        break;
+      case TOKEN.ne:
+        this.ir.push(OP.NE);
+        break;
+      case TOKEN.gt:
+        this.ir.push(OP.GT);
+        break;
+      case TOKEN.ge:
+        this.ir.push(OP.GE);
+        break;
+      case TOKEN.lt:
+        this.ir.push(OP.LT);
+        break;
+      case TOKEN.le:
+        this.ir.push(OP.LE);
+        break;
+      case TOKEN.and:
+        this.ir.push(OP.AND);
+        break;
+      case TOKEN.or:
+        this.ir.push(OP.OR);
+        break;
+      case TOKEN.xor:
+        this.ir.push(OP.XOR);
+        break;
+      case TOKEN.atan:
+        this.ir.push(OP.ATAN);
+        break;
+      case TOKEN.min:
+        this.ir.push(OP.MIN);
+        break;
+      case TOKEN.max:
+        this.ir.push(OP.MAX);
+        break;
+      default:
+        return false;
+    }
+    return true;
+  }
+
+  _compileTernary(node) {
+    if (!this._compileNode(node.cond)) {
+      return false;
+    }
+
+    this.ir.push(OP.IF, 0);
+    const ifPatch = this.ir.length - 1;
+
+    if (!this._compileNode(node.then)) {
+      return false;
+    }
+
+    this.ir.push(OP.JUMP, 0);
+    const jumpPatch = this.ir.length - 1;
+
+    this.ir[ifPatch] = this.ir.length; // IF jumps here on false
+    if (!this._compileNode(node.otherwise)) {
+      return false;
+    }
+
+    this.ir[jumpPatch] = this.ir.length; // JUMP lands here
+    return true;
+  }
+
+  compile(program) {
+    const outputs = new PSStackToTree().evaluate(program, this.nIn);
+    if (!outputs || outputs.length < this.nOut) {
+      return null;
+    }
+
+    for (let i = 0; i < this.nOut; i++) {
+      if (!this._compileNode(outputs[i])) {
+        return null;
+      }
+      const min = this.range[i * 2];
+      const max = this.range[i * 2 + 1];
+      this.ir.push(OP.STORE, i, min, max);
+    }
+
+    return new Float64Array(this.ir);
+  }
+
+  static execute(ir, src, srcOffset, dest, destOffset) {
+    let ip = 0,
+      sp = 0;
+    const n = ir.length;
+    const stack = PsJsCompiler.#stack;
+    const tmp = PsJsCompiler.#tmp;
+
+    while (ip < n) {
+      switch (ir[ip++] | 0) {
+        case OP.ARG:
+          stack[sp++] = src[srcOffset + (ir[ip++] | 0)];
+          break;
+        case OP.CONST:
+          stack[sp++] = ir[ip++];
+          break;
+        case OP.STORE: {
+          const slot = ir[ip++] | 0;
+          const min = ir[ip++];
+          const max = ir[ip++];
+          dest[destOffset + slot] = Math.max(Math.min(stack[--sp], max), min);
+          break;
+        }
+        case OP.IF: {
+          const tgt = ir[ip++];
+          if (stack[--sp] === 0) {
+            ip = tgt;
+          }
+          break;
+        }
+        case OP.JUMP:
+          ip = ir[ip];
+          break;
+        case OP.ABS:
+          stack[sp - 1] = Math.abs(stack[sp - 1]);
+          break;
+        case OP.NEG:
+          stack[sp - 1] = -stack[sp - 1];
+          break;
+        case OP.CEIL:
+          stack[sp - 1] = Math.ceil(stack[sp - 1]);
+          break;
+        case OP.FLOOR:
+          stack[sp - 1] = Math.floor(stack[sp - 1]);
+          break;
+        case OP.ROUND:
+          stack[sp - 1] = Math.floor(stack[sp - 1] + 0.5);
+          break;
+        case OP.TRUNC:
+          stack[sp - 1] = Math.trunc(stack[sp - 1]);
+          break;
+        case OP.NOT_B:
+          stack[sp - 1] = stack[sp - 1] !== 0 ? 0 : 1;
+          break;
+        case OP.NOT_N:
+          stack[sp - 1] = ~(stack[sp - 1] | 0);
+          break;
+        case OP.SQRT:
+          stack[sp - 1] = Math.sqrt(stack[sp - 1]);
+          break;
+        case OP.SIN:
+          stack[sp - 1] = Math.sin((stack[sp - 1] % 360) * _DEG_TO_RAD);
+          break;
+        case OP.COS:
+          stack[sp - 1] = Math.cos((stack[sp - 1] % 360) * _DEG_TO_RAD);
+          break;
+        case OP.LN:
+          stack[sp - 1] = Math.log(stack[sp - 1]);
+          break;
+        case OP.LOG10:
+          stack[sp - 1] = Math.log10(stack[sp - 1]);
+          break;
+        case OP.CVI:
+          stack[sp - 1] = Math.trunc(stack[sp - 1]) | 0;
+          break;
+        case OP.SHIFT: {
+          const amt = ir[ip++];
+          const v = stack[sp - 1] | 0;
+          if (amt > 0) {
+            stack[sp - 1] = v << amt;
+          } else if (amt < 0) {
+            stack[sp - 1] = v >> -amt;
+          } else {
+            stack[sp - 1] = v;
+          }
+          break;
+        }
+        case OP.ADD: {
+          const b = stack[--sp];
+          stack[sp - 1] += b;
+          break;
+        }
+        case OP.SUB: {
+          const b = stack[--sp];
+          stack[sp - 1] -= b;
+          break;
+        }
+        case OP.MUL: {
+          const b = stack[--sp];
+          stack[sp - 1] *= b;
+          break;
+        }
+        case OP.DIV: {
+          const b = stack[--sp];
+          stack[sp - 1] = b !== 0 ? stack[sp - 1] / b : 0;
+          break;
+        }
+        case OP.IDIV: {
+          const b = stack[--sp];
+          stack[sp - 1] = b !== 0 ? Math.trunc(stack[sp - 1] / b) : 0;
+          break;
+        }
+        case OP.MOD: {
+          const b = stack[--sp];
+          stack[sp - 1] = b !== 0 ? stack[sp - 1] % b : 0;
+          break;
+        }
+        case OP.POW: {
+          const b = stack[--sp];
+          stack[sp - 1] **= b;
+          break;
+        }
+        case OP.EQ: {
+          const b = stack[--sp];
+          stack[sp - 1] = stack[sp - 1] === b ? 1 : 0;
+          break;
+        }
+        case OP.NE: {
+          const b = stack[--sp];
+          stack[sp - 1] = stack[sp - 1] !== b ? 1 : 0;
+          break;
+        }
+        case OP.GT: {
+          const b = stack[--sp];
+          stack[sp - 1] = stack[sp - 1] > b ? 1 : 0;
+          break;
+        }
+        case OP.GE: {
+          const b = stack[--sp];
+          stack[sp - 1] = stack[sp - 1] >= b ? 1 : 0;
+          break;
+        }
+        case OP.LT: {
+          const b = stack[--sp];
+          stack[sp - 1] = stack[sp - 1] < b ? 1 : 0;
+          break;
+        }
+        case OP.LE: {
+          const b = stack[--sp];
+          stack[sp - 1] = stack[sp - 1] <= b ? 1 : 0;
+          break;
+        }
+        case OP.AND: {
+          const b = stack[--sp] | 0;
+          stack[sp - 1] = (stack[sp - 1] | 0) & b;
+          break;
+        }
+        case OP.OR: {
+          const b = stack[--sp] | 0;
+          stack[sp - 1] = stack[sp - 1] | 0 | b;
+          break;
+        }
+        case OP.XOR: {
+          const b = stack[--sp] | 0;
+          stack[sp - 1] = (stack[sp - 1] | 0) ^ b;
+          break;
+        }
+        case OP.ATAN: {
+          const b = stack[--sp];
+          const deg = Math.atan2(stack[sp - 1], b) * _RAD_TO_DEG;
+          stack[sp - 1] = deg < 0 ? deg + 360 : deg;
+          break;
+        }
+        case OP.MIN: {
+          const b = stack[--sp];
+          stack[sp - 1] = Math.min(stack[sp - 1], b);
+          break;
+        }
+        case OP.MAX: {
+          const b = stack[--sp];
+          stack[sp - 1] = Math.max(stack[sp - 1], b);
+          break;
+        }
+        case OP.TEE_TMP:
+          tmp[ir[ip++] | 0] = stack[sp - 1];
+          break;
+        case OP.LOAD_TMP:
+          stack[sp++] = tmp[ir[ip++] | 0];
+          break;
+      }
+    }
+  }
+}
+
+/**
+ * @param {string}   source
+ * @param {number[]} domain  – flat [min0,max0, …]
+ * @param {number[]} range   – flat [min0,max0, …]
+ * @returns {Float64Array|null}
+ */
+function compilePostScriptToIR(source, domain, range) {
+  return new PsJsCompiler(domain, range).compile(
+    parsePostScriptFunction(source)
+  );
+}
+
+/**
+ * Same calling convention as the Wasm wrapper:
+ *   fn(src, srcOffset, dest, destOffset)
+ *
+ * @param {string}   source
+ * @param {number[]} domain  – flat [min0,max0, …]
+ * @param {number[]} range   – flat [min0,max0, …]
+ * @returns {Function|null}
+ */
+function buildPostScriptJsFunction(source, domain, range) {
+  const ir = compilePostScriptToIR(source, domain, range);
+  if (!ir) {
+    return null;
+  }
+
+  return (src, srcOffset, dest, destOffset) => {
+    PsJsCompiler.execute(ir, src, srcOffset, dest, destOffset);
+  };
+}
+
+export { buildPostScriptJsFunction, compilePostScriptToIR };
diff --git a/src/core/postscript/wasm_compiler.js b/src/core/postscript/wasm_compiler.js
index 32e59d50f..b68d0a217 100644
--- a/src/core/postscript/wasm_compiler.js
+++ b/src/core/postscript/wasm_compiler.js
@@ -138,13 +138,8 @@ const _mathImportObject = {
   Math: Object.fromEntries(MATH_IMPORTS.map(([name]) => [name, Math[name]])),
 };
 
-// The compiler.
-//
-// After PSStackToTree converts the parser AST into a stack-free expression
-// tree, the compiler walks each output tree node recursively and emits Wasm
-// instructions that leave exactly one f64 value on the Wasm operand stack.
-// PsTernaryNode compiles to a value-returning `if/else/end` block — no
-// branch-buffer swapping or local-merging is needed.
+// Walks each PSStackToTree output node and emits Wasm, leaving one f64 per
+// output on the Wasm operand stack.  Ternary nodes compile to if/else/end.
 class PsWasmCompiler {
   static #initialized = false;
 
@@ -257,11 +252,12 @@ class PsWasmCompiler {
     this._nOut = range.length >> 1;
     this._range = range;
     this._code = [];
-    // Params 0..nIn-1 are automatically locals; extras start at _nextLocal.
+
+    // Params 0..nIn-1 are locals; extra locals start at _nextLocal.
     this._nextLocal = this._nIn;
+
     this._freeLocals = [];
-    // node → {local, remaining} for shared sub-expression caching (CSE).
-    this._sharedLocals = new Map();
+    this._sharedLocals = new Map(); // node → {local, remaining} for CSE
   }
 
   // Wasm emit helpers
diff --git a/test/unit/postscript_spec.js b/test/unit/postscript_spec.js
index dafc90394..569a3ad23 100644
--- a/test/unit/postscript_spec.js
+++ b/test/unit/postscript_spec.js
@@ -35,6 +35,7 @@ import {
   PsTernaryNode,
   PsUnaryNode,
 } from "../../src/core/postscript/ast.js";
+import { buildPostScriptJsFunction } from "../../src/core/postscript/js_evaluator.js";
 
 // Precision argument for toBeCloseTo() in trigonometric tests.
 const TRIGONOMETRY_EPS = 1e-10;
@@ -195,15 +196,23 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
      * For single-output functions returns a scalar; for multi-output an Array.
      */
     function compileAndRun(src, domain, range, args) {
-      const fn = buildPostScriptWasmFunction(src, domain, range);
-      if (!fn) {
+      const wasmFn = buildPostScriptWasmFunction(src, domain, range);
+      const jsFn = buildPostScriptJsFunction(src, domain, range);
+      if (!wasmFn) {
+        expect(jsFn).toBeNull();
         return null;
       }
+      expect(jsFn).not.toBeNull();
       const nOut = range.length >> 1;
       const srcBuf = new Float64Array(args);
-      const dest = new Float64Array(nOut);
-      fn(srcBuf, 0, dest, 0);
-      return nOut === 1 ? dest[0] : Array.from(dest);
+      const wasmDest = new Float64Array(nOut);
+      const jsDest = new Float64Array(nOut);
+      wasmFn(srcBuf, 0, wasmDest, 0);
+      jsFn(srcBuf, 0, jsDest, 0);
+      for (let i = 0; i < nOut; i++) {
+        expect(jsDest[i]).toBeCloseTo(wasmDest[i], 10);
+      }
+      return nOut === 1 ? wasmDest[0] : Array.from(wasmDest);
     }
 
     function readULEB128(bytes, offset) {
@@ -257,186 +266,161 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     // Arithmetic.
 
     it("compiles add", async function () {
-      const r = await compileAndRun(
-        "{ add }",
-        [0, 1, 0, 1],
-        [0, 2],
-        [0.3, 0.7]
-      );
+      const r = compileAndRun("{ add }", [0, 1, 0, 1], [0, 2], [0.3, 0.7]);
       expect(r).toBeCloseTo(1.0, 9);
     });
 
     it("compiles sub", async function () {
-      const r = await compileAndRun(
-        "{ sub }",
-        [0, 1, 0, 1],
-        [0, 1],
-        [0.8, 0.3]
-      );
+      const r = compileAndRun("{ sub }", [0, 1, 0, 1], [0, 1], [0.8, 0.3]);
       expect(r).toBeCloseTo(0.5, 9);
     });
 
     it("compiles mul", async function () {
-      const r = await compileAndRun("{ 0.5 mul }", [0, 1], [0, 1], [0.4]);
+      const r = compileAndRun("{ 0.5 mul }", [0, 1], [0, 1], [0.4]);
       expect(r).toBeCloseTo(0.2, 9);
     });
 
     it("compiles div", async function () {
-      const r = await compileAndRun("{ div }", [0, 10, 0, 10], [0, 10], [6, 3]);
+      const r = compileAndRun("{ div }", [0, 10, 0, 10], [0, 10], [6, 3]);
       expect(r).toBeCloseTo(2, 9);
     });
 
     it("div by zero returns 0", async function () {
-      const r = await compileAndRun("{ div }", [0, 10, 0, 10], [0, 10], [5, 0]);
+      const r = compileAndRun("{ div }", [0, 10, 0, 10], [0, 10], [5, 0]);
       expect(r).toBe(0);
     });
 
     it("compiles idiv", async function () {
-      const r = await compileAndRun(
-        "{ idiv }",
-        [0, 10, 1, 10],
-        [0, 10],
-        [7, 2]
-      );
+      const r = compileAndRun("{ idiv }", [0, 10, 1, 10], [0, 10], [7, 2]);
       expect(r).toBeCloseTo(3, 9);
     });
 
     it("idiv by zero returns 0", async function () {
-      const r = await compileAndRun(
-        "{ idiv }",
-        [0, 10, 0, 10],
-        [0, 10],
-        [5, 0]
-      );
+      const r = compileAndRun("{ idiv }", [0, 10, 0, 10], [0, 10], [5, 0]);
       expect(r).toBe(0);
     });
 
     it("compiles mod", async function () {
-      const r = await compileAndRun("{ mod }", [0, 10, 1, 10], [0, 10], [7, 3]);
+      const r = compileAndRun("{ mod }", [0, 10, 1, 10], [0, 10], [7, 3]);
       expect(r).toBeCloseTo(1, 9);
     });
 
     it("mod by zero returns 0", async function () {
-      const r = await compileAndRun("{ mod }", [0, 10, 0, 10], [0, 10], [5, 0]);
+      const r = compileAndRun("{ mod }", [0, 10, 0, 10], [0, 10], [5, 0]);
       expect(r).toBe(0);
     });
 
     it("compiles mod with constant divisor", async function () {
       // { 3 mod } — divisor is a compile-time constant, exercises the
       // constant-divisor branch in _compileModNode.
-      const r = await compileAndRun("{ 3 mod }", [0, 10], [0, 3], [7]);
+      const r = compileAndRun("{ 3 mod }", [0, 10], [0, 3], [7]);
       expect(r).toBeCloseTo(1, 9); // 7 mod 3 = 1
     });
 
     it("compiles integer xor (bitwise)", async function () {
       // { 5 xor } with an integer-typed arg — exercises the non-boolean path in
       // _compileBitwiseOperandI32 and the xor case in _compileBitwiseNode.
-      const r = await compileAndRun("{ 5 xor }", [-128, 127], [-128, 127], [3]);
+      const r = compileAndRun("{ 5 xor }", [-128, 127], [-128, 127], [3]);
       expect(r).toBeCloseTo(6, 9); // 3 XOR 5 = 6
     });
 
     it("compiles neg", async function () {
       // neg applied to a variable — the optimizer cannot fold this.
       // abs(neg(x)) is optimized to abs(x), so test neg alone.
-      const r = await compileAndRun("{ neg }", [-1, 1], [-1, 1], [-0.5]);
+      const r = compileAndRun("{ neg }", [-1, 1], [-1, 1], [-0.5]);
       expect(r).toBeCloseTo(0.5, 9);
     });
 
     it("compiles neg and abs", async function () {
-      const r = await compileAndRun("{ neg abs }", [-1, 1], [0, 1], [-0.8]);
+      const r = compileAndRun("{ neg abs }", [-1, 1], [0, 1], [-0.8]);
       expect(r).toBeCloseTo(0.8, 9);
     });
 
     it("compiles cvi (truncate to integer)", async function () {
-      const r = await compileAndRun("{ 1.7 add cvi }", [0, 2], [0, 4], [0.5]);
+      const r = compileAndRun("{ 1.7 add cvi }", [0, 2], [0, 4], [0.5]);
       expect(r).toBeCloseTo(2, 9); // trunc(0.5 + 1.7) = trunc(2.2) = 2
     });
 
     it("compiles cvr (identity on reals)", async function () {
-      const r = await compileAndRun("{ cvr }", [0, 1], [0, 1], [0.7]);
+      const r = compileAndRun("{ cvr }", [0, 1], [0, 1], [0.7]);
       expect(r).toBeCloseTo(0.7, 9);
     });
 
     // Math.
 
     it("compiles sqrt", async function () {
-      const r = await compileAndRun("{ sqrt }", [0, 100], [0, 10], [9]);
+      const r = compileAndRun("{ sqrt }", [0, 100], [0, 10], [9]);
       expect(r).toBeCloseTo(3, 9);
     });
 
     it("compiles floor", async function () {
-      const r = await compileAndRun("{ floor }", [-2, 2], [-2, 2], [1.7]);
+      const r = compileAndRun("{ floor }", [-2, 2], [-2, 2], [1.7]);
       expect(r).toBeCloseTo(1, 9);
     });
 
     it("compiles ceiling", async function () {
-      const r = await compileAndRun("{ ceiling }", [-2, 2], [-2, 2], [1.2]);
+      const r = compileAndRun("{ ceiling }", [-2, 2], [-2, 2], [1.2]);
       expect(r).toBeCloseTo(2, 9);
     });
 
     it("compiles round", async function () {
-      const r = await compileAndRun("{ round }", [-2, 2], [-2, 2], [1.5]);
+      const r = compileAndRun("{ round }", [-2, 2], [-2, 2], [1.5]);
       expect(r).toBeCloseTo(2, 9);
     });
 
     it("round uses round-half-up (0.5 rounds to 1, -0.5 rounds to 0)", async function () {
-      const r1 = await compileAndRun("{ round }", [-2, 2], [-2, 2], [0.5]);
+      const r1 = compileAndRun("{ round }", [-2, 2], [-2, 2], [0.5]);
       expect(r1).toBe(1);
-      const r2 = await compileAndRun("{ round }", [-2, 2], [-2, 2], [-0.5]);
+      const r2 = compileAndRun("{ round }", [-2, 2], [-2, 2], [-0.5]);
       expect(r2).toBe(0);
     });
 
     it("compiles truncate", async function () {
-      const r = await compileAndRun("{ truncate }", [-2, 2], [-2, 2], [-1.9]);
+      const r = compileAndRun("{ truncate }", [-2, 2], [-2, 2], [-1.9]);
       expect(r).toBeCloseTo(-1, 9);
     });
 
     it("compiles ln", async function () {
-      const r = await compileAndRun("{ ln }", [0.001, 10], [-10, 10], [Math.E]);
+      const r = compileAndRun("{ ln }", [0.001, 10], [-10, 10], [Math.E]);
       expect(r).toBeCloseTo(1, 9);
     });
 
     it("compiles log (base 10)", async function () {
-      const r = await compileAndRun("{ log }", [0.001, 1000], [-3, 3], [100]);
+      const r = compileAndRun("{ log }", [0.001, 1000], [-3, 3], [100]);
       expect(r).toBeCloseTo(2, 9);
     });
 
     it("compiles exp (base ^ exponent)", async function () {
-      const r = await compileAndRun(
-        "{ exp }",
-        [0, 10, 0, 10],
-        [0, 2000],
-        [2, 10]
-      );
+      const r = compileAndRun("{ exp }", [0, 10, 0, 10], [0, 2000], [2, 10]);
       expect(r).toBeCloseTo(1024, 6);
     });
 
     it("compiles x ^ -1 → 1/x (strength reduction)", async function () {
-      const r = await compileAndRun("{ -1 exp }", [0.1, 10], [0.1, 10], [2]);
+      const r = compileAndRun("{ -1 exp }", [0.1, 10], [0.1, 10], [2]);
       expect(r).toBeCloseTo(0.5, 9); // 1/2 = 0.5
     });
 
     it("compiles x ^ 3 → (x*x)*x (strength reduction)", async function () {
-      const r = await compileAndRun("{ 3 exp }", [0, 10], [0, 1000], [2]);
+      const r = compileAndRun("{ 3 exp }", [0, 10], [0, 1000], [2]);
       expect(r).toBeCloseTo(8, 9); // 2^3 = 8
     });
 
     it("compiles x ^ 4 → (x*x)*(x*x) (strength reduction)", async function () {
       // x^4 uses CSE: x*x is computed once and squared — exercises the
       // local_tee/local_get path in _compileStandardBinaryNode.
-      const r = await compileAndRun("{ 4 exp }", [0, 10], [0, 10000], [2]);
+      const r = compileAndRun("{ 4 exp }", [0, 10], [0, 10000], [2]);
       expect(r).toBeCloseTo(16, 9); // 2^4 = 16
     });
 
     // Trigonometry (degrees).
 
     it("compiles sin (degrees)", async function () {
-      const r = await compileAndRun("{ sin }", [-360, 360], [-1, 1], [90]);
+      const r = compileAndRun("{ sin }", [-360, 360], [-1, 1], [90]);
       expect(r).toBeCloseTo(1, TRIGONOMETRY_EPS);
     });
 
     it("compiles cos (degrees)", async function () {
-      const r = await compileAndRun("{ cos }", [-360, 360], [-1, 1], [0]);
+      const r = compileAndRun("{ cos }", [-360, 360], [-1, 1], [0]);
       expect(r).toBeCloseTo(1, TRIGONOMETRY_EPS);
     });
 
@@ -452,18 +436,13 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
 
     it("compiles atan (degrees, result in [0,360))", async function () {
       // atan(1, 1) = 45°
-      const r = await compileAndRun(
-        "{ atan }",
-        [-10, 10, -10, 10],
-        [0, 360],
-        [1, 1]
-      );
+      const r = compileAndRun("{ atan }", [-10, 10, -10, 10], [0, 360], [1, 1]);
       expect(r).toBeCloseTo(45, 6);
     });
 
     it("atan normalizes negative angles to [0,360)", async function () {
       // atan(-1, 1) would be -45°, should become 315°
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ atan }",
         [-10, 10, -10, 10],
         [0, 360],
@@ -475,33 +454,23 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     // Stack operators.
 
     it("compiles dup", async function () {
-      const r = await compileAndRun("{ dup mul }", [0, 1], [0, 1], [0.5]);
+      const r = compileAndRun("{ dup mul }", [0, 1], [0, 1], [0.5]);
       expect(r).toBeCloseTo(0.25, 9);
     });
 
     it("compiles exch", async function () {
-      const r = await compileAndRun(
-        "{ exch div }",
-        [0, 10, 0, 10],
-        [0, 10],
-        [1, 2]
-      );
+      const r = compileAndRun("{ exch div }", [0, 10, 0, 10], [0, 10], [1, 2]);
       expect(r).toBeCloseTo(2, 9); // 2 / 1
     });
 
     it("compiles pop", async function () {
-      const r = await compileAndRun(
-        "{ pop }",
-        [0, 1, 0, 1],
-        [0, 1],
-        [0.3, 0.7]
-      );
+      const r = compileAndRun("{ pop }", [0, 1, 0, 1], [0, 1], [0.3, 0.7]);
       expect(r).toBeCloseTo(0.3, 9); // 0.7 popped, 0.3 remains
     });
 
     it("compiles copy", async function () {
       // { 1 copy add }: one input a → stack [a, a] → add → [2a]
-      const r = await compileAndRun("{ 1 copy add }", [0, 1], [0, 2], [0.4]);
+      const r = compileAndRun("{ 1 copy add }", [0, 1], [0, 2], [0.4]);
       expect(r).toBeCloseTo(0.8, 9);
     });
 
@@ -592,7 +561,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     });
 
     it("compiles 3-input function", async function () {
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ add add }",
         [0, 1, 0, 1, 0, 1],
         [0, 3],
@@ -602,7 +571,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     });
 
     it("compiles 4-input function", async function () {
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ add add add }",
         [0, 1, 0, 1, 0, 1, 0, 1],
         [0, 4],
@@ -612,7 +581,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     });
 
     it("compiles 5-input function (default caller path)", async function () {
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ add add add add }",
         [0, 1, 0, 1, 0, 1, 0, 1, 0, 1],
         [0, 5],
@@ -624,38 +593,38 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     // Comparison / boolean.
 
     it("compiles eq", async function () {
-      const r = await compileAndRun("{ eq }", [0, 1, 0, 1], [0, 1], [0.5, 0.5]);
+      const r = compileAndRun("{ eq }", [0, 1, 0, 1], [0, 1], [0.5, 0.5]);
       expect(r).toBeCloseTo(1, 9);
     });
 
     it("compiles ne (not-equal)", async function () {
-      const r = await compileAndRun("{ 0.5 ne }", [0, 1], [0, 1], [0.3]);
+      const r = compileAndRun("{ 0.5 ne }", [0, 1], [0, 1], [0.3]);
       expect(r).toBeCloseTo(1, 9); // 0.3 ≠ 0.5 → true → 1
     });
 
     it("compiles lt (less-than)", async function () {
-      const r = await compileAndRun("{ 0.5 lt }", [0, 1], [0, 1], [0.3]);
+      const r = compileAndRun("{ 0.5 lt }", [0, 1], [0, 1], [0.3]);
       expect(r).toBeCloseTo(1, 9); // 0.3 < 0.5 → true → 1
     });
 
     it("compiles ge (greater-or-equal)", async function () {
-      const r = await compileAndRun("{ 0.5 ge }", [0, 1], [0, 1], [0.7]);
+      const r = compileAndRun("{ 0.5 ge }", [0, 1], [0, 1], [0.7]);
       expect(r).toBeCloseTo(1, 9); // 0.7 ≥ 0.5 → true → 1
     });
 
     it("compiles gt", async function () {
-      const r = await compileAndRun("{ gt }", [0, 1, 0, 1], [0, 1], [0.8, 0.3]);
+      const r = compileAndRun("{ gt }", [0, 1, 0, 1], [0, 1], [0.8, 0.3]);
       expect(r).toBeCloseTo(1, 9);
     });
 
     it("compiles le", async function () {
-      const r = await compileAndRun("{ le }", [0, 1, 0, 1], [0, 1], [0.3, 0.8]);
+      const r = compileAndRun("{ le }", [0, 1, 0, 1], [0, 1], [0.3, 0.8]);
       expect(r).toBeCloseTo(1, 9);
     });
 
     it("compiles true and false literals", async function () {
-      const t = await compileAndRun("{ true }", [], [0, 1], []);
-      const f = await compileAndRun("{ false }", [], [0, 1], []);
+      const t = compileAndRun("{ true }", [], [0, 1], []);
+      const f = compileAndRun("{ false }", [], [0, 1], []);
       expect(t).toBeCloseTo(1, 9);
       expect(f).toBeCloseTo(0, 9);
     });
@@ -663,7 +632,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     // Conditionals.
 
     it("compiles ifelse — true branch taken", async function () {
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ dup 0.5 gt { 2 mul } { 0.5 mul } ifelse }",
         [0, 1],
         [0, 2],
@@ -673,7 +642,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     });
 
     it("compiles ifelse — false branch taken", async function () {
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ dup 0.5 gt { 2 mul } { 0.5 mul } ifelse }",
         [0, 1],
         [0, 2],
@@ -684,7 +653,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
 
     it("compiles if — condition true", async function () {
       // { dup 1 gt { pop 1 } if } — clamp x to 1 from above
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ dup 1 gt { pop 1 } if }",
         [0, 2],
         [0, 2],
@@ -694,7 +663,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     });
 
     it("compiles if — condition false", async function () {
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ dup 1 gt { pop 1 } if }",
         [0, 2],
         [0, 2],
@@ -733,29 +702,19 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
 
     it("clamps output to declared range", async function () {
       // mul exceeds range [0, 0.5] → result clamped
-      const r = await compileAndRun(
-        "{ add }",
-        [0, 1, 0, 1],
-        [0, 0.5],
-        [0.4, 0.4]
-      );
+      const r = compileAndRun("{ add }", [0, 1, 0, 1], [0, 0.5], [0.4, 0.4]);
       expect(r).toBeCloseTo(0.5, 9);
     });
 
     // Bitwise.
 
     it("compiles bitshift left (literal shift)", async function () {
-      const r = await compileAndRun("{ 3 bitshift }", [0, 256], [0, 256], [1]);
+      const r = compileAndRun("{ 3 bitshift }", [0, 256], [0, 256], [1]);
       expect(r).toBeCloseTo(8, 9); // 1 << 3
     });
 
     it("compiles bitshift right (negative literal shift)", async function () {
-      const r = await compileAndRun(
-        "{ -2 bitshift }",
-        [-256, 256],
-        [-256, 256],
-        [8]
-      );
+      const r = compileAndRun("{ -2 bitshift }", [-256, 256], [-256, 256], [8]);
       expect(r).toBeCloseTo(2, 9); // 8 >> 2
     });
 
@@ -764,7 +723,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // b |= 0x80 branch in _emitULEB128.
       // Wasm i32.shl uses shift % 32, so 128 % 32 = 0 →
       // left-shift by 0 = identity.
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ 128 bitshift }",
         [-1000, 1000],
         [-1000, 1000],
@@ -779,7 +738,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // exercising the byte |= 0x80 branch in unsignedLEB128.
       const src =
         "{ 1 add 1 add 1 add 1 add 1 add 1 add 1 add 1 add 1 add 1 add 1 add 1 add 1 add }";
-      const r = await compileAndRun(src, [0, 1], [0, 14], [0]);
+      const r = compileAndRun(src, [0, 1], [0, 14], [0]);
       expect(r).toBeCloseTo(13, 9);
     });
 
@@ -807,13 +766,13 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
 
     it("compiles boolean not (logical NOT)", async function () {
       // 0.5 0.5 eq → true (1.0); not → false (0.0)
-      const r = await compileAndRun("{ dup eq not }", [0, 1], [0, 1], [0.5]);
+      const r = compileAndRun("{ dup eq not }", [0, 1], [0, 1], [0.5]);
       expect(r).toBeCloseTo(0, 9);
     });
 
     it("compiles integer not (bitwise NOT)", async function () {
       // ~5 = -6
-      const r = await compileAndRun("{ not }", [-256, 256], [-256, 256], [5]);
+      const r = compileAndRun("{ not }", [-256, 256], [-256, 256], [5]);
       expect(r).toBeCloseTo(-6, 9);
     });
 
@@ -821,7 +780,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
 
     it("ifelse with comparison condition (true branch)", async function () {
       // x > 0.5: comparison emitted directly as i32, no f64 round-trip.
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ 0.5 gt { 1 } { 0 } ifelse }",
         [0, 1],
         [0, 1],
@@ -831,7 +790,7 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     });
 
     it("ifelse with comparison condition (false branch)", async function () {
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ 0.5 gt { 1 } { 0 } ifelse }",
         [0, 1],
         [0, 1],
@@ -846,9 +805,9 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // node is a PsBinaryNode(and) — exercises the i32_trunc_f64_s fallback
       // in _compileNodeAsBoolI32.
       const src = "{ dup 0.3 gt exch 0.7 lt and { 1 } { 0 } ifelse }";
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.5]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.5]);
       expect(r0).toBeCloseTo(1, 9); // 0.5 in (0.3, 0.7)
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.2]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.2]);
       expect(r1).toBeCloseTo(0, 9); // 0.2 outside range
     });
 
@@ -856,9 +815,9 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // not(and(two comparisons)) — exercises the boolean `not` path in
       // _compileNodeAsBoolI32 (recursive call + i32.eqz).
       const src = "{ dup 0.3 gt exch 0.7 lt and not { 1 } { 0 } ifelse }";
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.5]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.5]);
       expect(r0).toBeCloseTo(0, 9); // 0.5 in (0.3, 0.7) → not → false
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.2]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.2]);
       expect(r1).toBeCloseTo(1, 9); // 0.2 outside range → not → true
     });
 
@@ -868,18 +827,18 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // and(x>0.3, x<0.7) used as the direct output (not as ternary condition)
       // — exercises _compileBitwiseOperandI32 with boolean operands.
       const src = "{ dup 0.3 gt exch 0.7 lt and }";
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.5]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.5]);
       expect(r0).toBeCloseTo(1, 9);
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.2]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.2]);
       expect(r1).toBeCloseTo(0, 9);
     });
 
     it("boolean-or of two comparisons as standalone output", async function () {
       // or(x<0.3, x>0.7): true when x is outside [0.3, 0.7].
       const src = "{ dup 0.3 lt exch 0.7 gt or }";
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.2]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.2]);
       expect(r0).toBeCloseTo(1, 9);
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.5]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.5]);
       expect(r1).toBeCloseTo(0, 9);
     });
 
@@ -888,9 +847,9 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // _compileNodeAsBoolI32 for the operand, eliminating all f64/i32
       // round-trips.
       const src = "{ dup 0.3 gt exch 0.7 lt and not }";
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.5]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.5]);
       expect(r0).toBeCloseTo(0, 9); // inside → and=true → not=false
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.2]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.2]);
       expect(r1).toBeCloseTo(1, 9); // outside → and=false → not=true
     });
 
@@ -899,11 +858,11 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // Each ternary condition goes through _compileNodeAsBoolI32.
       const src =
         "{ dup 0.3 lt { pop 0 } { dup 0.7 gt { pop 1 } { pop 0.5 } ifelse } ifelse }";
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.1]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.1]);
       expect(r0).toBeCloseTo(0, 9);
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.9]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.9]);
       expect(r1).toBeCloseTo(1, 9);
-      const r2 = await compileAndRun(src, [0, 1], [0, 1], [0.5]);
+      const r2 = compileAndRun(src, [0, 1], [0, 1], [0.5]);
       expect(r2).toBeCloseTo(0.5, 9);
     });
 
@@ -911,9 +870,9 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // or(x<0.3, x>0.7) as ternary condition — exercises the TOKEN.or case
       // in the boolean and/or/xor branch of _compileNodeAsBoolI32.
       const src = "{ dup 0.3 lt exch 0.7 gt or { 1 } { 0 } ifelse }";
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.2]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.2]);
       expect(r0).toBeCloseTo(1, 9); // 0.2 < 0.3 → true
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.5]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.5]);
       expect(r1).toBeCloseTo(0, 9); // 0.5 inside → false
     });
 
@@ -922,10 +881,10 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // _compileNodeAsBoolI32; true when exactly one condition holds.
       const src = "{ dup 0.5 lt exch 0.3 gt xor { 1 } { 0 } ifelse }";
       // x=0.4: 0.4<0.5=true, 0.4>0.3=true → xor=false → 0
-      const r0 = await compileAndRun(src, [0, 1], [0, 1], [0.4]);
+      const r0 = compileAndRun(src, [0, 1], [0, 1], [0.4]);
       expect(r0).toBeCloseTo(0, 9);
       // x=0.2: 0.2<0.5=true, 0.2>0.3=false → xor=true → 1
-      const r1 = await compileAndRun(src, [0, 1], [0, 1], [0.2]);
+      const r1 = compileAndRun(src, [0, 1], [0, 1], [0.2]);
       expect(r1).toBeCloseTo(1, 9);
     });
 
@@ -933,19 +892,9 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // The condition is the raw input arg (numeric, not boolean), so
       // _compileNodeAsBoolI32 falls through to the general path and emits
       // f64.const 0 / f64.ne to convert to i32.
-      const r0 = await compileAndRun(
-        "{ { 1 } { 0 } ifelse }",
-        [0, 1],
-        [0, 1],
-        [0.7]
-      );
+      const r0 = compileAndRun("{ { 1 } { 0 } ifelse }", [0, 1], [0, 1], [0.7]);
       expect(r0).toBeCloseTo(1, 9); // 0.7 ≠ 0 → truthy → 1
-      const r1 = await compileAndRun(
-        "{ { 1 } { 0 } ifelse }",
-        [0, 1],
-        [0, 1],
-        [0]
-      );
+      const r1 = compileAndRun("{ { 1 } { 0 } ifelse }", [0, 1], [0, 1], [0]);
       expect(r1).toBeCloseTo(0, 9); // 0 → falsy → 0
     });
 
@@ -955,34 +904,29 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
       // (x+1)^2: the x^2→x*x strength reduction creates PsBinaryNode(mul,
       // add_node, add_node) where add_node is non-trivial — exercises the
       // local_tee/local_get path in _compileStandardBinaryNode.
-      const r = await compileAndRun("{ 1 add 2 exp }", [0, 10], [0, 100], [3]);
+      const r = compileAndRun("{ 1 add 2 exp }", [0, 10], [0, 100], [3]);
       expect(r).toBeCloseTo(16, 9); // (3+1)^2 = 16
     });
 
     it("shared non-trivial operand uses local_tee (x+2)^2 via dup", async function () {
       // `2 add dup mul`: dup of the add node gives PsBinaryNode(mul, add, add)
       // with the same reference twice — exercises the local_tee/local_get path.
-      const r = await compileAndRun(
-        "{ 2 add dup mul }",
-        [0, 10],
-        [0, 100],
-        [3]
-      );
+      const r = compileAndRun("{ 2 add dup mul }", [0, 10], [0, 100], [3]);
       expect(r).toBeCloseTo(25, 9); // (3+2)^2 = 25
     });
 
     it("compiles x^3 without changing behavior", async function () {
-      const r = await compileAndRun("{ 3 exp }", [0, 10], [0, 1000], [2]);
+      const r = compileAndRun("{ 3 exp }", [0, 10], [0, 1000], [2]);
       expect(r).toBeCloseTo(8, 9);
     });
 
     it("compiles x^4 without changing behavior", async function () {
-      const r = await compileAndRun("{ 4 exp }", [0, 10], [0, 10000], [2]);
+      const r = compileAndRun("{ 4 exp }", [0, 10], [0, 10000], [2]);
       expect(r).toBeCloseTo(16, 9);
     });
 
     it("compiles x^-1 without changing behavior", async function () {
-      const r = await compileAndRun("{ -1 exp }", [1, 10], [0, 1], [4]);
+      const r = compileAndRun("{ -1 exp }", [1, 10], [0, 1], [4]);
       expect(r).toBeCloseTo(0.25, 9);
     });
 
@@ -1031,19 +975,19 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
     // min/max fold and related runtime tests.
 
     it("compiles x^0.25 → sqrt(sqrt(x))", async function () {
-      const r = await compileAndRun("{ 0.25 exp }", [0, 16], [0, 2], [16]);
+      const r = compileAndRun("{ 0.25 exp }", [0, 16], [0, 2], [16]);
       expect(r).toBeCloseTo(2, 9); // 16^0.25 = 2
     });
 
     it("compiles neg(a − b) → b − a", async function () {
       // neg(x - 3) = 3 - x; at x=1 → 2
-      const r = await compileAndRun("{ 3 sub neg }", [0, 10], [0, 10], [1]);
+      const r = compileAndRun("{ 3 sub neg }", [0, 10], [0, 10], [1]);
       expect(r).toBeCloseTo(2, 9);
     });
 
     it("compiles min(max(x, 0.8), 0.5) → constant 0.5", async function () {
       // Absorption: max result always >= 0.8 > 0.5, so min is always 0.5.
-      const r = await compileAndRun(
+      const r = compileAndRun(
         "{ dup 0.8 lt { pop 0.8 } { } ifelse " +
           "dup 0.5 gt { pop 0.5 } { } ifelse }",
         [0, 1],
@@ -1055,14 +999,14 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
 
     it("min/max fold: upper clamp emits f64.min", async function () {
       // x > 1 → clamp to 1; x ≤ 1 → pass through.
-      const r1 = await compileAndRun(
+      const r1 = compileAndRun(
         "{ dup 1 gt { pop 1 } { } ifelse }",
         [0, 2],
         [0, 2],
         [2]
       );
       expect(r1).toBeCloseTo(1, 9);
-      const r2 = await compileAndRun(
+      const r2 = compileAndRun(
         "{ dup 1 gt { pop 1 } { } ifelse }",
         [0, 2],
         [0, 2],
@@ -1073,14 +1017,14 @@ describe("PostScript Type 4 lexer, parser, and Wasm compiler", function () {
 
     it("min/max fold: lower clamp emits f64.max", async function () {
       // x < 0 → clamp to 0; x ≥ 0 → pass through.
-      const r1 = await compileAndRun(
+      const r1 = compileAndRun(
         "{ dup 0 lt { pop 0 } { } ifelse }",
         [-1, 1],
         [0, 1],
         [-0.5]
       );
       expect(r1).toBeCloseTo(0, 9);
-      const r2 = await compileAndRun(
+      const r2 = compileAndRun(
         "{ dup 0 lt { pop 0 } { } ifelse }",
         [-1, 1],
         [0, 1],
diff --git a/web/internal/multiline_view.css b/web/internal/multiline_view.css
index 9a8dc67ab..d40befc75 100644
--- a/web/internal/multiline_view.css
+++ b/web/internal/multiline_view.css
@@ -157,6 +157,7 @@
     font-size: 0.8em;
     color: var(--muted-color);
     user-select: none;
+    height: 22px;
   }
 
   .mlc-num-item.mlc-match {
diff --git a/web/internal/tree_view.css b/web/internal/tree_view.css
index 1198a66f1..d9fc07469 100644
--- a/web/internal/tree_view.css
+++ b/web/internal/tree_view.css
@@ -179,6 +179,7 @@
   display: block;
   white-space: nowrap;
   padding-inline-start: 0.5em;
+  height: 22px;
 }
 
 .raw-bytes-stream {
diff --git a/web/internal/tree_view.js b/web/internal/tree_view.js
index 605fed98d..4302d4885 100644
--- a/web/internal/tree_view.js
+++ b/web/internal/tree_view.js
@@ -235,6 +235,32 @@ class TreeView {
    * into the ref's children container, avoiding an extra toggle level).
    */
   #buildChildren(value, doc, container) {
+    if (this.#isPSFunction(value)) {
+      for (const [k, v] of Object.entries(value.dict)) {
+        container.append(this.#renderNode(k, v, doc));
+      }
+      const srcNode = this.#makeNodeEl("source");
+      const srcLabel = `[PostScript, ${value.psLines.length} lines]`;
+      const srcLabelEl = this.#makeSpan("stream-label", srcLabel);
+      srcNode.append(
+        this.#makeExpandable(srcLabelEl, srcLabel, c =>
+          this.#buildPSFunctionPanel(value, c, srcLabelEl)
+        )
+      );
+      container.append(srcNode);
+      if (value.jsCode !== null) {
+        const jsNode = this.#makeNodeEl("js");
+        const jsLabel = "[JS equivalent]";
+        const jsLabelEl = this.#makeSpan("stream-label", jsLabel);
+        jsNode.append(
+          this.#makeExpandable(jsLabelEl, jsLabel, c =>
+            this.#buildJSCodePanel(value.jsCode, c)
+          )
+        );
+        container.append(jsNode);
+      }
+      return;
+    }
     if (this.#isStream(value)) {
       for (const [k, v] of Object.entries(value.dict)) {
         container.append(this.#renderNode(k, v, doc));
@@ -310,6 +336,8 @@ class TreeView {
         span.append(this.#makeSpan("bracket", "]"));
         return span;
       }
+      case "brace":
+        return this.#makeSpan("bracket", token.value);
       case "dict": {
         const span = document.createElement("span");
         span.className = "token-dict";
@@ -355,6 +383,8 @@ class TreeView {
         return String(token.value);
       case "null":
         return "null";
+      case "brace":
+        return token.value;
       case "array":
         return `[ ${token.value.map(t => this.#tokenToText(t)).join(" ")} ]`;
       case "dict": {
@@ -470,6 +500,96 @@ class TreeView {
     return btn;
   }
 
+  // Fills container with a PostScript source panel (indented, token-coloured).
+  #buildPSSourcePanel(psLines, container, actions = null) {
+    const mc = new MultilineView({
+      total: psLines.length,
+      lineClass: "content-stream ps-source-stream",
+      getText: i => {
+        const { tokens } = psLines[i];
+        return tokens.map(t => this.#tokenToText(t)).join(" ");
+      },
+      actions,
+      makeLineEl: (i, isHighlighted) => {
+        const line = document.createElement("div");
+        line.className = "content-stm-instruction";
+        if (isHighlighted) {
+          line.classList.add("mlc-match");
+        }
+        const content = document.createElement("span");
+        const { indent, tokens } = psLines[i];
+        if (indent > 0) {
+          content.style.paddingInlineStart = `${indent * 1.5}em`;
+        }
+        for (let j = 0; j < tokens.length; j++) {
+          if (j > 0) {
+            content.append(document.createTextNode(" "));
+          }
+          content.append(this.#renderToken(tokens[j]));
+        }
+        line.append(content);
+        return line;
+      },
+    });
+    container.append(mc.element);
+    return mc;
+  }
+
+  // Fills container with a JS code panel (plain monospace lines).
+  #buildJSCodePanel(jsCode, container, actions = null) {
+    const lines = jsCode.split("\n");
+    while (lines.at(-1) === "") {
+      lines.pop();
+    }
+    const mc = new MultilineView({
+      total: lines.length,
+      lineClass: "content-stream js-code-stream",
+      getText: i => lines[i],
+      actions,
+      makeLineEl: (i, isHighlighted) => {
+        const el = document.createElement("div");
+        el.className = "content-stm-instruction";
+        if (isHighlighted) {
+          el.classList.add("mlc-match");
+        }
+        el.append(document.createTextNode(lines[i]));
+        return el;
+      },
+    });
+    container.append(mc.element);
+    return mc;
+  }
+
+  // PS source panel with parsed/raw toggle and an expandable JS equivalent.
+  #buildPSFunctionPanel(val, container, labelEl = null) {
+    let isParsed = true;
+    let currentPanel = null;
+    const rawLines = val.source.split(/\r?\n|\r/);
+    if (rawLines.at(-1) === "") {
+      rawLines.pop();
+    }
+    const parsedLabel = `[PostScript, ${val.psLines.length} lines]`;
+    const rawLabel = `[PostScript, ${rawLines.length} raw lines]`;
+
+    const rebuild = () => {
+      currentPanel?.destroy();
+      currentPanel = null;
+      container.replaceChildren();
+      if (labelEl) {
+        labelEl.textContent = isParsed ? parsedLabel : rawLabel;
+      }
+      const btn = this.#makeParseToggleBtn(isParsed, () => {
+        isParsed = !isParsed;
+        rebuild();
+      });
+      currentPanel = isParsed
+        ? this.#buildPSSourcePanel(val.psLines, container, btn)
+        : this.#buildRawBytesPanel(val.source, container, btn);
+    };
+
+    rebuild();
+  }
+
   // Fills container with the content stream panel (parsed or raw), with a
   // toggle button in the toolbar that swaps the view in-place.
   #buildContentStreamPanel(val, container, labelEl = null) {
@@ -538,6 +658,15 @@ class TreeView {
       return this.#renderContentStream(value);
     }
 
+    // PostScript Type 4 function stream
+    if (this.#isPSFunction(value)) {
+      return this.#renderExpandable(
+        "[PostScript Function]",
+        "stream-label",
+        container => this.#buildChildren(value, doc, container)
+      );
+    }
+
     // Stream → expandable showing dict entries + byte count or image preview
     if (this.#isStream(value)) {
       return this.#renderExpandable("[Stream]", "stream-label", container =>
@@ -841,6 +970,17 @@ class TreeView {
   #isFormXObjectStream(val) {
     return this.#isStream(val) && val.contentStream === true;
   }
+
+  // PostScript Type 4 function: { dict, psFunction: true, psLines, jsCode }.
+  #isPSFunction(val) {
+    return (
+      val !== null &&
+      typeof val === "object" &&
+      !Array.isArray(val) &&
+      Object.prototype.hasOwnProperty.call(val, "dict") &&
+      val.psFunction === true
+    );
+  }
 }
 
 export { TreeView };