1 files changed, 240 insertions, 0 deletions
diff --git a/prototypes/workbench/compiler.test.mjs b/prototypes/workbench/compiler.test.mjs
new file mode 100644
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+++ b/prototypes/workbench/compiler.test.mjs
@@ -0,0 +1,240 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { readFile } from 'node:fs/promises';
+import { compile, LIMITS } from './web/compiler.mjs';
+
+function diagnostic(source, pattern, line, column) {
+  assert.throws(() => compile(source), error => {
+    assert.match(error.message, pattern);
+    assert.ok(Number.isInteger(error.line) && error.line > 0);
+    assert.ok(Number.isInteger(error.column) && error.column > 0);
+    if (line !== undefined) assert.equal(error.line, line);
+    if (column !== undefined) assert.equal(error.column, column);
+    return true;
+  });
+}
+
+// A small independent evaluator checks compiler lowering. The product executes
+// these instructions in Zig; the VM has its own native and integration checks.
+function evaluate(program, start, length, values, dt = 0) {
+  const stack = [];
+  for (let pc = start; pc < start + length; pc++) {
+    const instruction = program.instructions[pc];
+    const { op, arg, value } = instruction;
+    if (op === 0) stack.push(value);
+    else if (op === 1) stack.push(values[arg]);
+    else if (op === 2) stack.push(dt);
+    else if (op === 7) stack.push(-stack.pop());
+    else if (op === 16) stack.push(Number(!stack.pop()));
+    else if (op === 19) {
+      const high = stack.pop(), low = stack.pop(), x = stack.pop();
+      assert.ok(low <= high); stack.push(Math.min(Math.max(x, low), high));
+    } else if (op === 20) values[arg] = stack.pop();
+    else if (op === 21) { if (!stack.pop()) pc = arg - 1; }
+    else {
+      const right = stack.pop(), left = stack.pop();
+      const operations = {
+        3: () => left + right, 4: () => left - right, 5: () => left * right,
+        6: () => left / right, 8: () => Number(left < right),
+        9: () => Number(left <= right), 10: () => Number(left > right),
+        11: () => Number(left >= right), 12: () => Number(left === right),
+        13: () => Number(left !== right), 14: () => Number(Boolean(left) && Boolean(right)),
+        15: () => Number(Boolean(left) || Boolean(right)),
+        17: () => Math.min(left, right), 18: () => Math.max(left, right),
+      };
+      assert.ok(operations[op], `Unknown opcode ${op}`);
+      stack.push(operations[op]());
+    }
+    assert.ok(stack.every(Number.isFinite));
+  }
+  return stack;
+}
+
+function dispatch(program, event, values, dt = 0) {
+  for (const handler of program.handlers.filter(handler => handler.event === event)) {
+    assert.deepEqual(evaluate(program, handler.start, handler.length, values, dt), []);
+  }
+}
+
+test('a blank document is an empty program with no implied behavior', () => {
+  const result = compile('');
+  for (const field of ['states', 'inputs', 'views', 'instructions', 'handlers']) assert.deepEqual(result[field], []);
+  assert.equal(result.metrics.sourceBytes, 0);
+  assert.equal(result.metrics.maxStack, 0);
+  assert.deepEqual(compile('# comment only\n;').instructions, []);
+});
+
+test('forward references and separate state/input namespaces preserve declaration IDs', () => {
+  const program = compile('on tap.down { second = tap + first }\ntext label(0,0,second)\nstate first = -2\nstate tap = +3\ninput tap = Space\nstate second = .5e2');
+  assert.deepEqual(program.states.map(state => state.name), ['first', 'tap', 'second']);
+  assert.equal(program.handlers[0].event, 1);
+  const values = program.states.map(state => state.initial);
+  dispatch(program, 1, values);
+  assert.deepEqual(values, [-2, 3, 1]);
+  const binding = program.views[0].bindings.value;
+  assert.deepEqual(evaluate(program, binding.start, binding.length, values), [1]);
+});
+
+test('ordered assignments, repeated handlers, and condition evaluation once', () => {
+  const program = compile(`state x = 1
+input tap = Enter
+on tap.down {
+  if x == 1 {
+    x = 0
+    x = x + 5
+  }
+}
+on tap.down { x = x * 2 }
+on tap.up { x = x - 1 }`);
+  const values = [1];
+  dispatch(program, 1, values);
+  assert.equal(values[0], 10);
+  dispatch(program, 2, values);
+  assert.equal(values[0], 9);
+  const branch = program.instructions.find(instruction => instruction.op === 21);
+  assert.equal(branch.arg, program.handlers[0].start + program.handlers[0].length);
+});
+
+test('nested branches use absolute forward targets and skip correct bodies', () => {
+  const program = compile(`state x = 0
+text label(0, 0, x)
+on frame {
+  if x > 0 {
+    x = 8
+    if x == 8 { x = 9 }
+  }
+  x = x + 1
+}`);
+  const values = [0];
+  dispatch(program, 0, values, 1 / 60); assert.equal(values[0], 1);
+  dispatch(program, 0, values, 1 / 60); assert.equal(values[0], 10);
+  const handler = program.handlers[0];
+  program.instructions.forEach((instruction, pc) => {
+    if (instruction.op === 21) assert.ok(instruction.arg > pc && instruction.arg <= handler.start + handler.length);
+  });
+});
+
+test('operator precedence, associativity, unary and builtin function lowering', () => {
+  const expressions = new Map([
+    ['2 + 3 * 4', 14], ['8 - 3 - 2', 3], ['12 / 3 / 2', 2],
+    ['-2 * -3', 6], ['!0 + !4', 1], ['1 || 0 && 0', 1],
+    ['1 < 2 && 2 <= 2 && 4 > 3 && 4 >= 4', 1],
+    ['3 == 3 && 3 != 4', 1], ['clamp(max(3, 9) - min(4, 7), 0, 4)', 4],
+  ]);
+  for (const [source, expected] of expressions) {
+    const program = compile(`state x = 0\non frame { x = ${source} }`);
+    const values = [0]; dispatch(program, 0, values, 1 / 60);
+    assert.equal(values[0], expected, source);
+  }
+  const eager = compile('state x = 0\non frame { x = 1 || x / 0 }');
+  assert.ok(eager.instructions.some(instruction => instruction.op === 6));
+  assert.ok(!eager.instructions.some(instruction => instruction.op === 21));
+});
+
+test('multiline parentheses, scientific literals, comments, and string escapes', () => {
+  const program = compile(`state x = 1e-2 # comment
+box tile(
+  (x +
+    2), 0, max(
+      1, 2), 4,
+  "#AABBCC")
+text label(0, 0, x, "# count: \\\"value\\\" \\n")
+on frame { x = x + dt }`);
+  assert.equal(program.views[0].color, '#AABBCC');
+  assert.equal(program.views[1].prefix, '# count: "value" \n');
+  const values = [.01]; dispatch(program, 0, values, 1 / 60);
+  assert.equal(values[0], .01 + 1 / 60);
+  const binding = program.views[0].bindings.x;
+  assert.deepEqual(evaluate(program, binding.start, binding.length, values), [values[0] + 2]);
+});
+
+test('all instruction fields are numeric and carry original source line', () => {
+  const program = compile('state x = 0\non frame {\n x = x + dt\n}');
+  for (const instruction of program.instructions) {
+    assert.deepEqual(Object.keys(instruction), ['op', 'arg', 'value', 'line']);
+    assert.ok(Object.values(instruction).every(Number.isFinite));
+    assert.equal(instruction.line, 3);
+  }
+});
+
+test('contextual declaration words remain valid names outside reserved builtins', () => {
+  const program = compile('state if = 1\nstate state = 2\non frame { if = if + state }');
+  const values = [1, 2]; dispatch(program, 0, values, 1 / 60);
+  assert.deepEqual(values, [3, 2]);
+});
+
+test('unknown and reserved symbols have useful one-based locations', () => {
+  diagnostic('state x = 0\non frame {\n  x = missing\n}', /Unknown state missing/, 3, 7);
+  diagnostic('on missing.down {}', /Unknown input missing/, 1, 4);
+  diagnostic('on frame { absent = 1 }', /Unknown state absent/, 1, 12);
+  for (const name of ['frame', 'dt', 'min', 'max', 'clamp']) {
+    diagnostic(`state ${name} = 0`, /Reserved name/, 1, 7);
+    diagnostic(`input ${name} = Space`, /Reserved name/);
+  }
+  diagnostic('text clock(0, 0, dt)', /dt is only available in handlers/);
+});
+
+test('duplicates, unsupported keys, initializers, and invalid syntax are rejected', () => {
+  const invalid = [
+    ['state x=0\nstate x=1', /Duplicate state/],
+    ['input tap=Space\ninput tap=Enter', /Duplicate input/],
+    ['input tap=Space\ninput other=Space', /Duplicate keyboard/],
+    ['box a(0,0,1,1,"#000000")\ncircle a(0,0,1,"#000000")', /Duplicate view/],
+    ['input tap=Escape', /Unsupported keyboard/],
+    ['state x=1+2', /Expected newline/],
+    ['state x=1e999', /finite/],
+    ['state x=NaN', /numeric state initializer/],
+    ['on tap.click {}', /Expected down or up/],
+    ['on frame.down {}', /Expected {/],
+    ['state x=0\non frame { x = min(1) }', /min expects 2/],
+    ['state x=0\non frame { x = clamp(1,2) }', /clamp expects 3/],
+    ['state x=0\non frame { x = 1 +\n2 }', /Expected a number/],
+    ['text a(0,0,1,"broken)', /Unterminated string/],
+    ['text a(0,0,1,"bad\\q")', /Unsupported string escape/],
+    ['box a(0,0,1,1,"blue")', /Color must use/],
+    ['state x=0 @', /Unexpected character/],
+    ['on frame {', /assignment, if, or closing brace/],
+    ['state x = 0 state y = 1', /Expected newline/],
+  ];
+  for (const [source, pattern] of invalid) diagnostic(source, pattern);
+});
+
+test('document, declaration, instruction, and nesting limits reject overflow', () => {
+  diagnostic('#' + '한'.repeat(11000), /32768 UTF-8 bytes/);
+  diagnostic(Array.from({ length: 33 }, (_, i) => `state s${i}=0`).join('\n'), /32 states/);
+  diagnostic(Array.from({ length: 9 }, (_, i) => `input i${i}=Digit${i}`).join('\n'), /8 inputs/);
+  diagnostic(Array.from({ length: 25 }, (_, i) => `text t${i}(0,0,0)`).join('\n'), /24 views/);
+  diagnostic('on frame {}\n'.repeat(65), /64 handlers/);
+  diagnostic(`state x=0\non frame {\n${'x=1\n'.repeat(257)}}`, /512 instructions/);
+  assert.equal(compile(`state x=0\non frame {\n${'x=1\n'.repeat(256)}}`).instructions.length, LIMITS.instructions);
+  diagnostic(`state x=0\non frame { x=${'('.repeat(65)}1${')'.repeat(65)} }`, /nesting exceeds 64/);
+  diagnostic(`on frame { ${'if 1 { '.repeat(65)}${'}\n'.repeat(66)}`, /nesting exceeds 64/);
+  // Right-nested clamp's two waiting operands exceed the stack before its depth limit.
+  let deep = '0';
+  for (let i = 0; i < 33; i++) deep = `clamp(0,0,${deep})`;
+  diagnostic(`text stack(0,0,${deep})`, /stack exceeds 64/);
+});
+
+test('every supported input maps to a bounded ordered event ID', () => {
+  const keys = ['Space', 'Enter', 'ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown', 'KeyZ', 'Digit9'];
+  const program = compile(keys.map((key, i) => `input i${i}=${key}\non i${i}.down {}\non i${i}.up {}`).join('\n'));
+  assert.deepEqual(program.handlers.map(handler => handler.event), Array.from({ length: 16 }, (_, i) => i + 1));
+});
+
+test('optional examples compile and charge behavior is entirely authored', async () => {
+  for (const name of ['counter', 'charge', 'toggle']) {
+    const program = compile(await readFile(new URL(`./examples/${name}.pure`, import.meta.url), 'utf8'));
+    assert.ok(program.instructions.length <= LIMITS.instructions);
+    assert.ok(program.views.length > 0);
+    if (name === 'charge') {
+      const values = program.states.map(state => state.initial);
+      dispatch(program, 1, values);
+      for (let frame = 0; frame < 90; frame++) dispatch(program, 0, values, 1 / 60);
+      assert.equal(values[0], 1); assert.equal(values[1], 1); assert.equal(values[2], 240);
+      dispatch(program, 2, values); assert.deepEqual(values, [0, 0, 240, -460]);
+      dispatch(program, 0, values, 1 / 60); assert.ok(values[2] < 240);
+      for (let frame = 0; frame < 120; frame++) dispatch(program, 0, values, 1 / 60);
+      assert.equal(values[2], 240); assert.equal(values[3], 0);
+    }
+  }
+});