constant_fold.mjs

// consumes <stdin> and performs constant folding
// echo '"use strict";"_"[0],1+2;' | node constant_fold.js
import _NodePath from '../NodePath';
const {NodePath} = _NodePath;
import _WalkCombinator from '../WalkCombinator';
const {WalkCombinator} = _WalkCombinator;

const $CONSTEXPR = Symbol.for('$CONSTEXTR');
const $CONSTVALUE = Symbol.for('$CONSTVALUE');
const IS_EMPTY = path => {
  return (path.node.type === 'BlockStatement' && path.node.body.length === 0) ||
    path.node.type === 'EmptyStatement';
};
const IN_PRAGMA_POS = path => {
  if (path.parent && Array.isArray(path.parent.node)) {
    const siblings = path.parent.node;
    for (let i = 0; i < path.key; i++) {
      // preceded by non-pragma
      if (
        siblings[i].type !== 'ExpressionStatement' ||
        !IS_CONSTEXPR(siblings[i].expression) ||
        typeof CONSTVALUE(siblings[i].expression) !== 'string'
      ) {
        return false;
      }
    }
  }
  return true;
};
const IS_PRAGMA = path => {
  if (path.parent && Array.isArray(path.parent.node)) {
    const siblings = path.parent.node;
    for (let i = 0; i < path.key + 1; i++) {
      // preceded by non-pragma
      if (
        siblings[i].type !== 'ExpressionStatement' ||
        !IS_CONSTEXPR(siblings[i].expression) ||
        typeof CONSTVALUE(siblings[i].expression) !== 'string'
      ) {
        return false;
      }
    }
  }
  return true;
};
// worst case is the completion value
const IS_NOT_COMPLETION = path => {
  while (true) {
    if (!path.parent) {
      return true;
    }
    if (
      Array.isArray(path.parent.node) &&
      path.key !== path.parent.node.length - 1
    ) {
      return true;
    }
    path = path.parent;
    while (Array.isArray(path.node)) {
      path = path.parent;
    }
    if (/Function/.test(path.node.type)) {
      return true;
    } else if (path.node.type === 'Program') {
      return false;
    }
  }
};
const REMOVE_IF_EMPTY = path => {
  if (IS_EMPTY(path)) REMOVE(path);
  return null;
};
const REPLACE_IF_EMPTY = (path, folded) => {
  if (IS_EMPTY(path)) return REPLACE(path, folded);
  return path;
};
const REMOVE = path => {
  if (Array.isArray(path.parent.node)) {
    path.parent.node.splice(path.key, 1);
  } else {
    path.parent.node[path.key] = null;
  }
  return null;
};
const REPLACE = (path, folded) => {
  const replacement = new NodePath(path.parent, folded, path.key);
  path.parent.node[path.key] = folded;
  return replacement;
};
// no mutation, this is an atomic value
const NEG_ZERO = Object.freeze({
  [$CONSTEXPR]: true,
  type: 'UnaryExpression',
  operator: '-',
  argument: Object.freeze({
    [$CONSTEXPR]: true,
    type: 'Literal',
    value: 0,
  }),
});
const INFINITY = Object.freeze({
  [$CONSTEXPR]: true,
  type: 'BinaryExpression',
  operator: '/',
  left: Object.freeze({
    [$CONSTEXPR]: true,
    type: 'Literal',
    value: 1,
  }),
  right: Object.freeze({
    [$CONSTEXPR]: true,
    type: 'Literal',
    value: 0,
  }),
});
const NEG_INFINITY = Object.freeze({
  [$CONSTEXPR]: true,
  type: 'BinaryExpression',
  operator: '/',
  left: Object.freeze({
    [$CONSTEXPR]: true,
    type: 'Literal',
    value: 1,
  }),
  right: NEG_ZERO,
});
const EMPTY = Object.freeze({
  [$CONSTEXPR]: true,
  type: 'EmptyStatement',
});
const NULL = Object.freeze({
  [$CONSTEXPR]: true,
  type: 'Literal',
  value: null,
});
const NAN = Object.freeze({
  [$CONSTEXPR]: true,
  type: 'BinaryExpression',
  operator: '/',
  left: Object.freeze({
    [$CONSTEXPR]: true,
    type: 'Literal',
    value: 0,
  }),
  right: Object.freeze({
    [$CONSTEXPR]: true,
    type: 'Literal',
    value: 0,
  }),
});
const UNDEFINED = Object.freeze({
  [$CONSTEXPR]: true,
  type: 'UnaryExpression',
  operator: 'void',
  argument: Object.freeze({
    [$CONSTEXPR]: true,
    type: 'Literal',
    value: 0,
  }),
});
// ESTree doesn't like negative numeric literals
// this also preserves -0
const IS_UNARY_NEGATIVE = node => {
  if (
    node.type === 'UnaryExpression' &&
    node.operator === '-' &&
    typeof node.argument.value === 'number' &&
    node.argument.value === node.argument.value &&
    node.argument.type === 'Literal'
  ) {
    return true;
  }
  return false;
};
const IS_CONSTEXPR = node => {
  if (typeof node !== 'object' || node === null) {
    return false;
  }
  // DONT CALCULATE THINGS MULTIPLE TIMES!!@!@#
  if (node[$CONSTEXPR]) return true;
  if (node.type === 'ArrayExpression') {
    for (let i = 0; i < node.elements.length; i++) {
      const element = node.elements[i];
      // hole == null
      if (element !== null && !IS_CONSTEXPR(element)) {
        return false;
      }
    }
    return true;
  }
  if (node.type === 'ObjectExpression') {
    for (let i = 0; i < node.properties.length; i++) {
      const element = node.properties[i];
      if (element.kind !== 'init') return false;
      if (element.method) return false;
      let key;
      if (element.computed) {
        // be sure {["y"]:1} works
        if (!IS_CONSTEXPR(element.key)) {
          return false;
        }
      }
      if (!IS_CONSTEXPR(element.value)) return false;
    }
    return true;
  }
  if (node.type === 'Literal' || IS_UNDEFINED(node) || IS_NAN(node)) {
    return true;
  }
  if (IS_UNARY_NEGATIVE(node)) {
    return true;
  }
  return false;
};
const IS_NAN = node => {
  return node === NAN;
};
const IS_UNDEFINED = node => {
  return node === UNDEFINED;
};
const CONSTVALUE = node => {
  if (node[$CONSTVALUE]) {
    return node[$CONSTVALUE];
  }
  if (IS_UNDEFINED(node)) return void 0;
  if (IS_NAN(node)) return +'_';
  if (!IS_CONSTEXPR(node)) throw new Error('Not a CONSTEXPR');
  if (node.type === 'ArrayExpression') {
    let ret = [];
    ret.length = node.elements.length;
    for (let i = 0; i < node.elements.length; i++) {
      if (node.elements[i] !== null) {
        ret[i] = CONSTVALUE(node.elements[i]);
      }
    }
    return ret;
  }
  if (node.type === 'ObjectExpression') {
    let ret = Object.create(null);
    for (let i = 0; i < node.properties.length; i++) {
      const element = node.properties[i];
      let key;
      if (element.computed) {
        key = `${CONSTVALUE(element.key)}`;
      }
      else {
        key = element.key.name;
      }
      Object.defineProperty(ret, key, {
        // duplicate keys...
        configurable: true,
        writable: true,
        value: CONSTVALUE(element.value),
        enumerable: true
      });
    }
    Object.freeze(ret);
    return ret;
  }
  if (IS_UNARY_NEGATIVE(node)) {
    return -node.argument.value;
  }
  if (node.regex !== void 0) {
    return new RegExp(node.regex.pattern, node.regex.flags);
  }
  return node.value;
};
const CONSTEXPRS = new Map();
CONSTEXPRS.set(void 0, UNDEFINED);
CONSTEXPRS.set(+'_', NAN);
CONSTEXPRS.set(null, NULL);
const TO_CONSTEXPR = value => {
  if (value === -Infinity) {
    return NEG_INFINITY;
  }
  if (value === Infinity) {
    return INFINITY;
  }
  let is_neg_zero = 1 / value === -Infinity;
  if (is_neg_zero) return NEG_ZERO;
  if (CONSTEXPRS.has(value)) {
    return CONSTEXPRS.get(value);
  }
  if (typeof value === 'number') {
    if (value < 0) {
      const CONSTEXPR = Object.freeze({
        [$CONSTEXPR]: true,
        [$CONSTVALUE]: value,
        type: 'UnaryExpression',
        operator: '-',
        argument: Object.freeze({ type: 'Literal', value: -value }),
      });
      CONSTEXPRS.set(value, CONSTEXPR);
      return CONSTEXPR;
    }
  }
  if (
    value === null ||
    typeof value === 'number' ||
    typeof value === 'boolean' ||
    typeof value === 'string'
  ) {
    const CONSTEXPR = Object.freeze({
      [$CONSTEXPR]: true,
      [$CONSTVALUE]: value,
      type: 'Literal',
      value,
    });
    CONSTEXPRS.set(value, CONSTEXPR);
    return CONSTEXPR;
  }
  // have to generate new one every time :-/
  if (Array.isArray(value)) {
    return Object.freeze({
      [$CONSTEXPR]: true,
      type: 'ArrayExpression',
      elements: Object.freeze(value.map(TO_CONSTEXPR)),
    });
  }
  if (typeof value === 'object' && Object.getPrototypeOf(value) === Object.getPrototypeOf({}) && [...Object.getOwnPropertySymbols(value)].length === 0) {
    return Object.freeze({
      [$CONSTEXPR]: true,
      type: 'ObjectExpression',
      properties: Object.freeze(
        [...Object.getOwnPropertyKeys(value)].map(key => {
          if (!('value' in Object.getOwnProperty(value, key))) {
            throw Error('Not a CONSTVALUE (found a setter or getter?)');
          }
          return {
            type: 'Property',
            kind: 'init',
            method: false,
            shorthand: false,
            computed: true,
            key: {
              type: 'Literal',
              value: key
            },
            value: TO_CONSTEXPR(value[key])
          }
        })),
      });
  }
  throw Error('Not a CONSTVALUE (did you pass a RegExp?)');
};

// THIS DOES NOT HANDLE NODE SPECIFIC CASES LIKE IfStatement
const FOLD_EMPTY = function*(path) {
  if (
    path &&
    path.node &&
    path.parent &&
    Array.isArray(path.parent.node) &&
    IS_EMPTY(path)
  ) {
    REMOVE(path);
    return yield;
  }
  return yield path;
};

// THIS DOES NOT HANDLE NODE SPECIFIC CASES LIKE IfStatement
const FOLD_TEMPLATE = function*(path) {
  if (
    path &&
    path.node &&
    path.type === 'TemplateLiteral'
  ) {
    let updated = false;
    for (let i = 0; i < path.node.exressions.length; i++) {
      if (IS_CONSTEXPR(path.node.expressions[i])) {
        //let 
      }
    }
  }
  return yield path;
};
const FOLD_EXPR_STMT = function*(path) {
  // TODO: enforce completion value checking
  if (path && path.node && path.node.type === 'ExpressionStatement') {
    // merge all the adjacent expression statements into sequences
    if (Array.isArray(path.parent.node)) {
      // could have nodes after it
      const siblings = path.parent.node;
      if (!IS_PRAGMA(path)) {
        if (path.key < siblings.length - 1) {
          const mergeable = [path.node];
          for (let needle = path.key + 1; needle < siblings.length; needle++) {
            if (siblings[needle].type !== 'ExpressionStatement') {
              break;
            }
            mergeable.push(siblings[needle]);
          }
          if (mergeable.length > 1) {
            siblings.splice(path.key, mergeable.length, {
              type: 'ExpressionStatement',
              expression: {
                type: 'SequenceExpression',
                expressions: mergeable.reduce(
                  (acc, es) => {
                    if (es.expression.type == 'SequenceExpression') {
                      return [...acc, ...es.expression.expressions];
                    } else {
                      return [...acc, es.expression];
                    }
                  },
                  []
                ),
              },
            });
            return path;
          }
        }
      }
    }
    if (IS_NOT_COMPLETION(path) && IS_CONSTEXPR(path.node.expression)) {
      return REPLACE(path, EMPTY);
    }
  }
  return yield path;
};
const FOLD_WHILE = function*(path) {
  if (path && path.node) {
    if (path.node.type === 'DoWhileStatement') {
      console.error('FOLD_DOWHILE');
      REPLACE_IF_EMPTY(path.get(['body']), EMPTY);
    }
    if (path.node.type === 'WhileStatement') {
      console.error('FOLD_WHILE');
      let { test, consequent, alternate } = path.node;
      if (IS_CONSTEXPR(test)) {
        test = CONSTVALUE(test);
        if (!test) {
          return REPLACE(path, EMPTY);
        }
      }
      REPLACE_IF_EMPTY(path.get(['body']), EMPTY);
    }
    if (path.node.type === 'ForStatement') {
      console.error('FOLD_FOR');
      REPLACE_IF_EMPTY(path.get(['body']), EMPTY);
      let { init, test, update } = path.node;
      let updated = false;
      if (init && IS_CONSTEXPR(init)) {
        updated = true;
        REPLACE(path.get(['init']), null);
      }
      if (test && IS_CONSTEXPR(test)) {
        let current = CONSTVALUE(test);
        let coerced = Boolean(current);
        // remove the test if it is always true
        if (coerced === true) {
          updated = true;
          REPLACE(path.get(['test']), null);
        } else if (coerced !== current) {
          updated = true;
          REPLACE(path.get(['test']), TO_CONSTEXPR(coerced));
        }
      }
      if (update && IS_CONSTEXPR(update)) {
        updated = true;
        REPLACE(path.get(['update']), null);
      }
      if (updated) {
        return path;
      }
    }
  }
  return yield path;
};
const FOLD_IF = function*(path) {
  if (path && path.node && path.node.type === 'IfStatement') {
    let { test, consequent, alternate } = path.node;
    const is_not_completion = IS_NOT_COMPLETION(path);
    if (is_not_completion && !alternate) {
      if (IS_EMPTY(path.get(['consequent']))) {
        console.error('FOLD_IF_EMPTY_CONSEQUENT');
        REPLACE(path, {
          type: 'ExpressionStatement',
          expression: test,
        });
        return path.parent;
      }
    }
    if (alternate) {
      if (alternate.type === consequent.type) {
        if (consequent.type === 'ExpressionStatement') {
          console.error('FOLD_IF_BOTH_EXPRSTMT');
          REPLACE(path, {
          type: 'ExpressionStatement', expression:
          {
            type: 'ConditionalExpression',
            test: test,
            consequent: consequent.expression,
            alternate: alternate.expression,
          }});
          return path.parent;
        }
        else if (consequent.type === 'ReturnStatement' ||
          consequent.type === 'ThrowStatement') {
          console.error('FOLD_IF_BOTH_COMPLETIONS');
          REPLACE(path, {
          type: 'ExpressionStatement', expression:{
            type: consequent.type,
            argument: {
              type: 'ConditionalExpression',
              test: test,
              consequent: consequent.argument,
              alternate: alternate.argument,
            }}
          });
          return path.parent;
        }
      }
    }
    else if (is_not_completion && consequent.type === 'ExpressionStatement') {
      console.error('FOLD_IF_NON_COMPLETION_TO_&&');
      REPLACE(path, {
        type: 'ExpressionStatement',
        expression: {
          type: 'BinaryExpression',
          operator: '&&',
          left: test,
          right: consequent.expression,
        }
      });
      return path.parent;
    }
    if (IS_CONSTEXPR(test)) {
      test = CONSTVALUE(test);
      if (test) {
        return REPLACE(path, consequent);
      }
      if (alternate) {
        return REPLACE(path, alternate);
      }
      return REPLACE(path, EMPTY);
    }
    consequent = path.get(['consequent']);
    let updated;
    if (consequent.node !== EMPTY) {
      REPLACE_IF_EMPTY(consequent, EMPTY);
      if (consequent.parent.node[consequent.key] === EMPTY) {
        updated = true;
      }
    }
    if (alternate) {
      alternate = path.get(['alternate']);
      REMOVE_IF_EMPTY(alternate);
      if (path.node.alternate === null) {
        updated = true;
      }
    }
    if (updated) {
      return path;
    }
  }
  return yield path;
};
const FOLD_SEQUENCE = function*(path) {
  if (path && path.node && path.node.type === 'SequenceExpression') {
    console.error('FOLD_SEQUENCE');
    // never delete the last value
    for (let i = 0; i < path.node.expressions.length - 1; i++) {
      if (IS_CONSTEXPR(path.node.expressions[i])) {
        path.node.expressions.splice(i, 1);
        i--;
      }
    }
    if (path.node.expressions.length === 1) {
      return REPLACE(path, path.node.expressions[0]);
    }
  }
  return yield path;
};
const FOLD_LOGICAL = function*(path) {
  if (path && path.node && path.node.type === 'LogicalExpression') {
    console.error('FOLD_LOGICAL');
    let { left, right, operator } = path.node;
    if (IS_CONSTEXPR(left)) {
      left = CONSTVALUE(left);
      if (operator === '||') {
        if (left) {
          return REPLACE(path, TO_CONSTEXPR(left));
        }
        return REPLACE(path, right);
      } else if (operator === '&&') {
        if (!left) {
          return REPLACE(path, TO_CONSTEXPR(left));
        }
        return REPLACE(path, right);
      }
    }
  }
  return yield path;
};
const FOLD_SWITCH = function*(path) {
  if (path && path.node && path.node.type === 'SwitchStatement') {
    let { discriminant, cases } = path.node;
    // if there are no cases, just become an expression
    if (cases.length === 0 && IS_NOT_COMPLETION(path)) {
      return REPLACE(path, {
        type: 'ExpressionStatement',
        expression: discriminant
      });
    }
    // if the discriminant is static
    //   remove any preceding non-matching static cases
    //   fold any trailing cases into the matching case
    if (cases.length > 1 && IS_CONSTEXPR(discriminant)) {
      const discriminant_value = CONSTVALUE(discriminant);
      for (var i = 0; i < cases.length; i++) {
        const test = cases[i].test;
        if (IS_CONSTEXPR(test)) {
          let test_value = CONSTVALUE(test);
          if (discriminant_value === test_value) {
            let new_consequent = cases[i].consequent;
            if (i < cases.length - 1) {
              for (let fallthrough of cases.slice(i+1)) {
                new_consequent.push(...fallthrough.consequent);
              }
            }
            cases[i].consequent = new_consequent;
            REPLACE(path.get(['cases']), [cases[i]]);
            return path;
          }
        }
        else {
          // we had a dynamic case need to bail
          break;
        }
      }
    }
  }
  return yield path;
};
const FOLD_UNREACHABLE = function*(path) {
  if (path && path.node && path.parent && Array.isArray(path.parent.node)) {
    if (path.node.type === 'ReturnStatement' ||
    path.node.type === 'ContinueStatement' ||
    path.node.type === 'BreakStatement' ||
    path.node.type === 'ThrowStatement') {
      const next_key = path.key + 1;
      path.parent.node.splice(next_key, path.parent.node.length - next_key);
    }
  }
  return yield path;
}
const FOLD_CONDITIONAL = function*(path) {
  if (path && path.node && path.node.type === 'ConditionalExpression') {
    console.error('FOLD_CONDITIONAL');
    let { test, consequent, alternate } = path.node;
    if (IS_CONSTEXPR(test)) {
      test = CONSTVALUE(test);
      if (test) {
        return REPLACE(path, consequent);
      }
      return REPLACE(path, alternate);
    }
  }
  return yield path;
};
const FOLD_BINARY = function*(path) {
  if (
    path &&
    path.node &&
    path.node.type === 'BinaryExpression' &&
    !IS_NAN(path.node)
  ) {
    console.error('FOLD_BINARY');
    let { left, right, operator } = path.node;
    if (operator === '==' || operator === '!=') {
      let updated = false;
      if (IS_UNDEFINED(left)) {
        updated = true;
        REPLACE(path.get(['left']), NULL);
      }
      if (IS_UNDEFINED(right)) {
        updated = true;
        REPLACE(path.get(['right']), NULL);
      }
      if (updated) {
        return path;
      }
    }
    if (path.node !== INFINITY && path.node !== NEG_INFINITY && IS_CONSTEXPR(left) && IS_CONSTEXPR(right)) {
      left = CONSTVALUE(left);
      right = CONSTVALUE(right);
      let value;
      if ((!left || typeof left !== 'object') && (!right || typeof right !== 'object')) {
        if (operator === '+') {
          value = left + right;
        } else if (operator === '-') {
          value = left - right;
        } else if (operator === '*') {
          value = left * right;
        } else if (operator === '/') {
          value = left / right;
        } else if (operator === '%') {
          value = left % right;
        } else if (operator === '==') {
          value = left == right;
        } else if (operator === '!=') {
          value = left != right;
        } else if (operator === '===') {
          value = left === right;
        } else if (operator === '!==') {
          value = left !== right;
        } else if (operator === '<') {
          value = left < right;
        } else if (operator === '<=') {
          value = left <= right;
        } else if (operator === '>') {
          value = left > right;
        } else if (operator === '>=') {
          value = left >= right;
        } else if (operator === '<<') {
          value = left << right;
        } else if (operator === '>>') {
          value = left >> right;
        } else if (operator === '>>>') {
          value = left >>> right;
        } else if (operator === '|') {
          value = left | right;
        } else if (operator === '&') {
          value = left & right;
        } else if (operator === '^') {
          value = left ^ right;
        }
      }
      else {
        if (operator === '==') value = false;
        if (operator === '===') value = false;
        if (operator === '!=') value = true;
        if (operator === '!==') value = true;
        if (operator === 'in' && typeof right === 'object' && right) {
          value = Boolean(Object.getOwnPropertyDescriptor(right, left));
        }
      }
      if (value !== void 0) {
        if (typeof value === 'string' || typeof value === 'boolean' || value === null) {
          return REPLACE(path, TO_CONSTEXPR(value));
        }
        if (typeof value === 'number') {
          return REPLACE(path, TO_CONSTEXPR(value));
        }
      }
    }
  }
  return yield path;
};
const FOLD_UNARY = function*(path) {
  if (path && path.node && path.node.type === 'UnaryExpression') {
    console.error('FOLD_UNARY');
    if (IS_CONSTEXPR(path.node)) {
      return yield path;
    }
    let { argument, operator } = path.node;
    if (IS_CONSTEXPR(argument)) {
      if (operator === 'void') {
        return REPLACE(path, UNDEFINED);
      }
      let value = CONSTVALUE(argument);
      if (operator === '-') {
        value = -value;
      } else if (operator === '+') {
        value = +value;
      } else if (operator === '~') {
        value = ~value;
      } else if (operator === '!') {
        value = !value;
      } else if (operator === 'typeof') {
        value = typeof value;
      } else if (operator === 'delete') {
        value = true;
      }
      return REPLACE(path, TO_CONSTEXPR(value));
    }
  }
  return yield path;
};
const FOLD_EVAL = function*(path) {
  if (path && path.node && path.node.type === 'CallExpression' &&
    path.node.callee.type === 'Identifier' && path.node.callee.name === 'eval') {
    console.error('FOLD_EVAL');
    if (path.node.arguments.length === 1 && path.node.arguments[0].type === 'Literal') {
      let result = esprima.parse(`${
        CONSTVALUE(path.node.arguments[0])
      }`);
      if (result.body.length === 1 && result.body[0].type === 'ExpressionStatement') {
        return REPLACE(path, result.body[0].expression);
      }
    }
  }
  return yield path;
}
const FOLD_MEMBER = function*(path) {
  if (path && path.node && path.node.type === 'MemberExpression') {
    console.error('FOLD_MEMBER');
    if (path.node.computed && path.node.property.type === 'Literal') {
      const current = `${CONSTVALUE(path.node.property)}`;
      if (typeof current === 'string' && /^[$_a-z][$_a-z\d]*$/i.test(current)) {
        path.node.computed = false;
        path.node.property = {
          type: 'Identifier',
          name: current,
        };
        return path;
      }
    }
    if (IS_CONSTEXPR(path.node.object)) {
      const value = CONSTVALUE(path.node.object);
      if (typeof value === 'string' || Array.isArray(value) || (value && typeof value === 'object')) {
        let key;
        if (IS_CONSTEXPR(path.node.property)) {
          key = `${CONSTVALUE(path.node.property)}`;
        }
        else if (!path.node.computed) {
          key = path.node.property.name;
        }
        if (key !== void 0) {
          const desc = Object.getOwnPropertyDescriptor(value, key);
          if (desc) {
            const folded = value[key];
            console.error('FOLDING', JSON.stringify(folded));
            if (IN_PRAGMA_POS(path) && typeof folded === 'string') {
              if (value.length > 1) {
                REPLACE(
                  path.get(['object']),
                  TO_CONSTEXPR(value.slice(key, key + 1))
                );
                REPLACE(path.get(['property']), TO_CONSTEXPR(0));
                return path;
              }
            } else {
              return REPLACE(path, TO_CONSTEXPR(value[key]));
            }
          }
        }
      }
    }
  }
  return yield path;
};

const $MIN = Symbol();
const MIN_TRUE = Object.freeze({
  [$MIN]: true,
  type: 'UnaryExpression',
  operator: '!',
  argument: Object.freeze({
    [$MIN]: true,
    type: 'Literal',
    value: 0
  })
});
const MIN_FALSE = Object.freeze({
  [$MIN]: true,
  type: 'UnaryExpression',
  operator: '!',
  argument: Object.freeze({
    [$MIN]: true,
    type: 'Literal',
    value: 1
  })
});
const MIN_REPLACEMENTS = new Map;
MIN_REPLACEMENTS.set(true, MIN_TRUE);
MIN_REPLACEMENTS.set(false, MIN_FALSE);
const MIN_VALUES = function*(path) {
  if (path && path.node && !path.node[$MIN] && IS_CONSTEXPR(path.node)) {
    let value = CONSTVALUE(path.node);
    if (MIN_REPLACEMENTS.has(value)) {
      console.error('MIN_VALUE', value)
      return REPLACE(path, MIN_REPLACEMENTS.get(value));
    }
  }
  return yield path;
}

import esprima from 'esprima';
import util from 'util';
import escodegen from 'escodegen';
const optimize = (src) => {
    const ROOT = new NodePath(
      null,
      esprima.parse(
        src,
        {
          // loc: true,
          // source: '<stdin>',
        }
      ),
      null
    );
    // all of these are things that could affect completion value positions
    const walk_expressions = WalkCombinator.pipe(
      ...[
        WalkCombinator.DEPTH_FIRST,
        {
          // We never work on Arrays
          *inputs(path) {
            if (Array.isArray(path)) return;
            return yield path;
          },
        },
        { inputs: FOLD_UNREACHABLE },
        { inputs: FOLD_IF },
        { inputs: FOLD_SWITCH },
        { inputs: FOLD_EXPR_STMT },
        { inputs: FOLD_CONDITIONAL },
        { inputs: FOLD_LOGICAL },
        { inputs: FOLD_BINARY },
        { inputs: FOLD_UNARY },
        { inputs: FOLD_SEQUENCE },
        { inputs: FOLD_MEMBER },
        { inputs: FOLD_EMPTY },
        { inputs: FOLD_WHILE },
        { inputs: FOLD_EVAL },
      ]
    ).walk(ROOT);
    for (const _ of walk_expressions) {
    }
    const minify = WalkCombinator.pipe(
      ...[
        WalkCombinator.DEPTH_FIRST,
        {
          // We never work on Arrays
          *inputs(path) {
            if (Array.isArray(path)) return;
            return yield path;
          },
        },
        { inputs: MIN_VALUES },
      ]
    ).walk(ROOT);
    for (const _ of minify) {
    }
    return ROOT;
}
import mississippi from 'mississippi';
process.stdin.pipe(
  mississippi.concat(buff => {
    const ROOT = optimize(`${buff}`)
    console.error(
      '%s',
      util.inspect(ROOT.node, {
        depth: null,
        colors: true,
      })
    );
    const out = escodegen.generate(ROOT.node);
    console.log(out);
  })
);