refactor: behavior

2020-06-23 11:19:59 -05:00 · 2020-06-23 11:19:59 -05:00 · abbab55d30
commit abbab55d30
parent de5b51b8ea
54 changed files with 675 additions and 1232 deletions
--- a/packages/behavior/item/actions.js
+++ b/packages/behavior/item/actions.js
@ -1,18 +1,15 @@
 import {compose, EventEmitter, TickingPromise} from '@avocado/core';

-import {Traversal} from './traversal';
-import {Traversals} from './traversals';
-
 const decorate = compose(
  EventEmitter,
 );

-export class Actions extends decorate(Traversals) {
+class Actions {

-  constructor() {
-    super();
+  constructor(expressions) {
+    this.expressions = 'function' === typeof expressions ? expressions() : expressions;
    this._index = 0;
-    this._actionPromise = null;
+    this.promise = null;
  }

  emitFinished() {
@ -33,29 +30,24 @@ export class Actions extends decorate(Traversals) {

  tick(context, elapsed) {
    // Empty resolves immediately.
-    if (this.traversals.length === 0) {
+    if (this.expressions.length === 0) {
      this.emitFinished();
      return;
    }
    // If the action promise ticks, tick it.
-    if (this._actionPromise && this._actionPromise instanceof TickingPromise) {
-      this._actionPromise.tick(elapsed);
+    if (this.promise && this.promise instanceof TickingPromise) {
+      this.promise.tick(elapsed);
      return;
    }
    // Actions execute immediately until a promise is made, or they're all
    // executed.
    while (true) {
      // Run the action.
-      const result = this.traversals[this.index].traverse(context);
+      const result = this.expressions[this.index](context);
      // Deferred result.
      if (result instanceof Promise) {
-        this._actionPromise = result;
-        // Handle any errors.
-        result.catch(console.error);
-        result.finally(() => {
-          // Finally, run the prologue.
-          this.prologue();
-        });
+        this.promise = result;
+        this.promise.catch(console.error).finally(() => this.prologue());
        break;
      }
      // Immediate result.
@ -68,19 +60,24 @@ export class Actions extends decorate(Traversals) {
  }

  parallel(context) {
-    // Map all traversals to results.
-    const results = this.traversals.map((traversal) => {
-      return traversal.traverse(context);
-    });
-    // Wrap all results in a TickingPromise.
+    const results = this.expressions.map((expression) => expression(context));
+    for (let i = 0; i < results.length; i++) {
+      const result = results[i];
+      if (result instanceof TickingPromise) {
        return TickingPromise.all(results);
      }
+      if (result instanceof Promise) {
+        return Promise.all(results);
+      }
+    }
+    return results;
+  }

  prologue() {
    // Clear out the action promise.
-    this._actionPromise = null;
+    this.promise = null;
    // Increment and wrap the index.
-    this.index = (this.index + 1) % this.traversals.length;
+    this.index = (this.index + 1) % this.expressions.length;
    // If rolled over, the actions are finished.
    if (0 === this.index) {
      this.emitFinished();
@ -103,3 +100,5 @@ export class Actions extends decorate(Traversals) {
  }

 }
+
+export default decorate(Actions);
--- a/packages/behavior/builders.js
+++ b/packages/behavior/builders.js
@ -1,36 +1,29 @@
-export function buildTraversal(path, value) {
-  const traversal = {
-    type: 'traversal',
-    steps: path.map((key) => {
-      return {
-        type: 'key',
-        key: key,
-      };
-    }),
+export function buildExpression(path, value) {
+  const expression = {
+    type: 'expression',
+    ops: path.map((key) => ({type: 'key', key: key})),
  };
  if ('undefined' !== typeof value) {
-    traversal.value = buildValue(value);
+    expression.value = buildValue(value);
  }
-  return traversal;
+  return expression;
 }

 export function buildInvoke (path, args = []) {
-  const traversal = buildTraversal(path);
-  traversal.steps.push({
+  const expression = buildExpression(path);
+  expression.ops.push({
    type: 'invoke',
-    args: args.map((arg) => {
-      return buildValue(arg);
-    }),
+    args: args.map((arg) => buildValue(arg)),
  });
-  return traversal;
+  return expression;
 }

 export function buildValue(value) {
  if (
    'object' === typeof value
    && (
-      'traversal' === value.type
-      || 'actions' === value.type
+      'expression' === value.type
+      || 'expressions' === value.type
      || 'condition' === value.type
    )
  ) {
@ -46,8 +39,6 @@ export function buildCondition(operator, operands) {
  return {
    type: 'condition',
    operator,
-    operands: operands.map((operand) => {
-      return buildValue(operand);
-    }),
+    operands: operands.map((operand) => buildValue(operand)),
  };
 }
--- a/packages/behavior/compile.js
+++ b/packages/behavior/compile.js
@ -0,0 +1,26 @@
+import memoize from 'lodash.memoize';
+import {invokeHookFlat, registerHooks} from 'scwp';
+
+export const compilers = memoize(() => (
+  invokeHookFlat('behaviorCompilers')
+    .reduce((r, results) => ({
+      ...r,
+      ...results,
+    }), {})
+));
+
+export default function compile(variant) {
+  const {[variant.type]: compiler} = compilers();
+  if (!compiler) {
+    return () => Promise.reject(new Error(`No compiler for '${variant.type}'`));
+  }
+  return compiler(variant);
+}
+
+registerHooks({
+  autoreg$accept: (type, M) => {
+    if ('hooks' === type && 'behaviorCompilers' in M) {
+      compilers.cache.clear();
+    }
+  },
+}, module.id);
--- a/packages/behavior/compilers.hooks.js
+++ b/packages/behavior/compilers.hooks.js
@ -0,0 +1,142 @@
+import {fastApply} from '@avocado/core';
+
+import compile from './compile';
+
+const render = (ops) => ops.reduce((rendered, op) => {
+  switch (op.type) {
+    case 'key':
+      return `${rendered ? `${rendered}.` : ''}${op.key}`;
+    case 'invoke':
+      return `${rendered}(${op.args.length > 0 ? '...' : ''})`;
+    default:
+      return rendered;
+  }
+}, '');
+
+function compileOp(op) {
+  let args;
+  if ('invoke' === op.type) {
+    args = op.args.map(compile);
+  }
+  return (context, previous, current) => {
+    switch (op.type) {
+      case 'key':
+        return current[op.key];
+      case 'invoke':
+        // Pass the context itself as the last arg.
+        const evaluated = args.map((fn) => fn(context)).concat(context);
+        // Promises are resolved transparently.
+        const apply = (args) => fastApply(previous, current, args);
+        return evaluated.some((arg) => arg instanceof Promise)
+          ? Promise.all(evaluated).then(apply)
+          : apply(evaluated);
+    }
+  };
+}
+
+function disambiguateResult(value, fn) {
+  const apply = (value) => fn(value);
+  return value instanceof Promise ? value.then(apply) : apply(value);
+}
+
+function compileExpression(expression) {
+  const assign = 'undefined' !== typeof expression.assign
+    ? compile(expression.assign)
+    : undefined;
+  const ops = expression.ops.map(compileOp);
+  const {ops: rawOps} = expression;
+  return (context) => {
+    let previous = null;
+    let shorted = false;
+    const [first, ...rest] = ops;
+    return rest.reduce((current, op, index) => disambiguateResult(current, (current) => {
+      if (shorted) {
+        return undefined;
+      }
+      let next = undefined;
+      const isLastOp = index === ops.length - 2;
+      if (!isLastOp || !assign) {
+        if ('undefined' === typeof current) {
+          const rendered = render(rawOps.slice(0, index + 2));
+          next = Promise.reject(new Error(`'${rendered}' is undefined`));
+          shorted = true;
+        }
+        else {
+          next = op(context, previous, current);
+        }
+      }
+      else {
+        const rawOp = rawOps[index + 1];
+        switch (rawOp.type) {
+          case 'key':
+            if ('object' === typeof current) {
+              current[rawOp.key] = assign(context);
+              next = undefined;
+            }
+            break;
+          case 'invoke':
+            const rendered = render(rawOps.slice(0, index + 2));
+            next = Promise.reject(new Error(`invalid assignment to function '${rendered}'`));
+            break;
+        }
+      }
+      previous = current;
+      current = next;
+      return current;
+    }), context.getValue(rawOps[0].key));
+  };
+}
+
+function compileCondition(condition) {
+  const {operator} = condition;
+  const operands = condition.operands.map(compile);
+  return (context) => {
+    switch (operator) {
+      case 'is':
+        return operands[0](context) === operands[1](context);
+      case 'isnt':
+        return operands[0](context) !== operands[1](context);
+      case '>':
+        return operands[0](context) > operands[1](context);
+      case '>=':
+        return operands[0](context) >= operands[1](context);
+      case '<':
+        return operands[0](context) < operands[1](context);
+      case '<=':
+        return operands[0](context) <= operands[1](context);
+      case 'or':
+        if (0 === operands.length) {
+          return true;
+        }
+        for (let i = 0; i < operands.length; i++) {
+          if (!!operands[i](context)) {
+            return true;
+          }
+        }
+        return false;
+      case 'and':
+        if (0 === operands.length) {
+          return true;
+        }
+        for (let i = 0; i < operands.length; i++) {
+          if (!operands[i](context)) {
+            return false;
+          }
+        }
+        return true;
+      case 'contains':
+        const haystack = operands[0](context);
+        const needle = operands[1](context);
+        return -1 !== haystack.indexOf(needle);
+    }
+  };
+}
+
+export function behaviorCompilers() {
+  return {
+    condition: (condition) => compileCondition(condition),
+    literal: ({value}) => (context) => value,
+    expression: (expression) => compileExpression(expression),
+    expressions: ({expressions}) => () => expressions.map(compileExpression),
+  };
+}
--- a/packages/behavior/context.js
+++ b/packages/behavior/context.js
@ -0,0 +1,74 @@
+import {arrayUnique, flatten, mapObject} from '@avocado/core';
+import memoize from 'lodash.memoize';
+import {invokeHookFlat, registerHooks} from 'scwp';
+
+export const globals = memoize(() => (
+  invokeHookFlat('behaviorContextGlobals')
+    .reduce((r, results) => ({
+      ...r,
+      ...results,
+    }), {})
+));
+
+export default class Context {
+
+  constructor(defaults = {}) {
+    this.map = new Map();
+    this.clear();
+    this.addObjectMap(defaults);
+  }
+
+  add(key, value, type = 'undefined') {
+    this.map.set(key, [value, type]);
+  }
+
+  addObjectMap(map) {
+    Object.entries(map)
+      .forEach(([key, [variable, type]]) => (
+        this.add(key, variable, type)
+      ));
+  }
+
+  all() {
+    return Array.from(this.map.keys())
+      .reduce((r, key) => ({
+        ...r,
+        [key]: this.get(key),
+      }), {});
+  }
+
+  clear() {
+    this.destroy();
+    this.add('context', this, 'context');
+    this.addObjectMap(globals());
+  }
+
+  destroy() {
+    this.map.clear();
+  }
+
+  get(key) {
+    return this.has(key) ? this.map.get(key) : [undefined, 'undefined'];
+  }
+
+  getValue(key) {
+    return this.get(key)[0];
+  }
+
+  getType(key) {
+    return this.get(key)[1];
+  }
+
+  has(key) {
+    return this.map.has(key);
+  }
+
+}
+
+registerHooks({
+  autoreg$accept: (type, M) => {
+    if ('hooks' === type && 'behaviorContextGlobals' in M) {
+      globals.cache.clear();
+    }
+  },
+}, module.id);
--- a/packages/behavior/context/context.hooks.js
+++ b/packages/behavior/context/context.hooks.js
@ -1,34 +0,0 @@
-import {Context} from './context';
-
-export function behaviorContextTypes() {
-  return {
-    bool: {
-      defaultLiteral: true,
-    },
-    context: {
-      children: {
-        add: {
-          type: 'void',
-          label: 'Add $2 as $1.',
-          args: [
-            ['key', {
-              type: 'string',
-            }],
-            ['value', {
-              type: 'any',
-            }],
-          ],
-        },
-      },
-    },
-    number: {
-      defaultLiteral: 0,
-    },
-    stream: {},
-    string: {
-      defaultLiteral: '',
-    },
-    void: {},
-  };
-}
-
--- a/packages/behavior/context/context.js
+++ b/packages/behavior/context/context.js
@ -1,237 +0,0 @@
-import {arrayUnique, flatten, mapObject} from '@avocado/core';
-import D from 'debug';
-import {invokeHookFlat} from 'scwp';
-
-import {fastApply, objectFromEntries} from '@avocado/core';
-
-const debug = D('@avocado:behavior:context');
-
-export class Context {
-
-  constructor(defaults = {}) {
-    this.typeMap = new Map();
-    this.variableMap = new Map();
-    this.initialize();
-    this.addObjectMap(defaults);
-  }
-
-  static allTypesDigraph() {
-    return Object.keys(this.types())
-      .reduce((r, type) => ({...r, [type]: this.typeDigraph(type)}), {});
-  }
-
-  static allTypesInvertedDigraph() {
-    const digraph = this.allTypesDigraph();
-    let inverted = {};
-    const fromTypes = Object.keys(digraph);
-    for (let i = 0; i < fromTypes.length; i++) {
-      const fromType = fromTypes[i];
-      const toTypes = digraph[fromType];
-      for (let j = 0; j < toTypes.length; j++) {
-        const toType = toTypes[j];
-        inverted[toType] = (inverted[toType] || {});
-        inverted[toType][fromType] = true;
-      }
-    }
-    inverted = mapObject(inverted, (types) => Object.keys(types));
-    inverted = mapObject(
-      inverted,
-      (types) => arrayUnique(flatten(types.map((type) => (inverted[type] || []).concat(type)))),
-    );
-    return inverted;
-  }
-
-  static describe(description, fn) {
-    const {type} = description;
-    fn.type = type;
-    return fn;
-  }
-
-  static globals() {
-    return invokeHookFlat('behaviorContextGlobals')
-      .reduce((r, results) => ({...r, ...results}), {});
-  }
-
-  static typeDigraph(type, marked = {}) {
-    const types = this.types();
-    if (marked[type] || !types[type]) {
-      marked[type] = true;
-      return [];
-    }
-    const description = this.typeDescription(type, undefined);
-    const subtypes = Object.keys(
-      Object.values(description.children)
-        .reduce((r, spec) => ({...r, [spec.type]: true}), {})
-    );
-    subtypes.forEach((type) => marked[type] = true);
-    return arrayUnique(
-      flatten(
-        subtypes.map(
-          (type) => this.typeDigraph(type, marked),
-        ),
-      ).concat(subtypes),
-    );
-  }
-
-  static typeDescription(type, variable) {
-    const types = this.types();
-    if (!types[type]) {
-      return {};
-    }
-    return {
-      children: {},
-      type,
-      ...('function' === typeof types[type] ? types[type](variable) : types[type])
-    };
-  }
-
-  static types() {
-    return invokeHookFlat('behaviorContextTypes')
-      .reduce((r, results) => ({
-        ...r,
-        ...results,
-      }), {});
-  }
-
-  add(key, value, type) {
-    this.typeMap.set(key, type);
-    this.variableMap.set(key, value);
-  }
-
-  addObjectMap(map) {
-    Object.entries(map).forEach(([key, [variable, type]]) => this.add(key, variable, type));
-  }
-
-  all() {
-    return Array.from(this.variableMap.keys())
-      .reduce((r, key) => ({...r, [key]: this.get(key)}), {});
-  }
-
-  initialize() {
-    this.typeMap.clear()
-    this.variableMap.clear()
-    this.add('context', this, 'context');
-    this.addObjectMap(this.constructor.globals());
-  }
-
-  clear() {
-    this.initialize();
-  }
-
-  destroy() {
-    this.typeMap.clear()
-    this.variableMap.clear();
-  }
-
-  get(key) {
-    const type = this.typeMap.has(key) ? this.typeMap.get(key) : 'undefined';
-    return [
-      this.variableMap.get(key),
-      type,
-    ];
-  }
-
-  static renderSteps(steps) {
-    return steps.reduce((rendered, step) => {
-      switch (step.type) {
-        case 'key':
-          if (rendered) {
-            rendered += '.';
-          }
-          rendered += step.key;
-          break;
-        case 'invoke':
-          rendered += `(${step.args.length > 0 ? '...' : ''})`;
-          break;
-      }
-      return rendered;
-    }, '');
-  }
-
-  static renderStepsUntilNow(steps, step) {
-    const stepsUntilNow = steps.slice(0, steps.indexOf(step));
-    return this.renderSteps(stepsUntilNow);
-  }
-
-  takeStep(value, fn) {
-    if (value instanceof Promise) {
-      return value.then((value) => {
-        return fn(value);
-      });
-    }
-    else {
-      return fn(value);
-    }
-  }
-
-  traverse(traversal) {
-    const {steps, value} = traversal;
-    return this.traverseAndDo(steps, (node, previousNode, step, index) => {
-      const isLastStep = index === steps.length - 2;
-      // Traverse if we're not at the final step with a value.
-      if (!isLastStep || !value) {
-        return this.traverseOneStep(steps, previousNode, node, step);
-      }
-      // Try to set the value.
-      switch (step.type) {
-        case 'key':
-          if ('object' === typeof node) {
-            return node[step.key] = value.get(this);
-          }
-        case 'invoke':
-          const rendered = this.constructor.renderStepsUntilNow(steps, step);
-          debug(`invalid assignment to function "${rendered}"`);
-          return;
-      }
-    });
-  }
-
-  traverseAndDo(steps, fn) {
-    const [first, ...rest] = steps;
-    if ('key' !== first.type) {
-      throw new TypeError(`First step in a traversal must be type "key"`);
-    }
-    let previousNode = null;
-    return rest.reduce((node, step, index) => {
-      return this.takeStep(node, (node) => {
-        const result = fn(node, previousNode, step, index);
-        previousNode = node;
-        return result;
-      });
-    }, this.variableMap.get(first.key));
-  }
-
-  traverseOneStep(steps, previousNode, node, step) {
-    if ('undefined' === typeof node) {
-      const rendered = this.constructor.renderStepsUntilNow(steps, step);
-      debug(`"${rendered}" is traversed through but undefined`);
-      return;
-    }
-    switch (step.type) {
-      case 'key':
-        return node[step.key];
-      case 'invoke':
-        const args = step.args.map((arg) => arg.get(this));
-        // Pass the context itself as the last arg.
-        args.push(this);
-        // Any arg promises will be resolved; the arg values will be passed
-        // transparently to the invocation.
-        let hasPromise = false;
-        for (let i = 0; i < args.length; i++) {
-          if (args[i] instanceof Promise) {
-            hasPromise = true;
-            break;
-          }
-        }
-        if (hasPromise) {
-          return Promise.all(args).then((args) => {
-            return fastApply(previousNode, node, args);
-          });
-        }
-        else {
-          return fastApply(previousNode, node, args);
-        }
-    }
-  }
-
-}
--- a/packages/behavior/context/flow.hooks.js
+++ b/packages/behavior/context/flow.hooks.js
@ -1,65 +0,0 @@
-import {Context} from './context';
-
-class Flow {
-
-  static conditional(condition, actions, context) {
-    if (condition.get(context)) {
-      return actions.serial(context);
-    }
-  };
-
-  static parallel(actions, context) {
-    return actions.parallel(context);
-  }
-
-  static serial(actions, context) {
-    return actions.serial(context);
-  }
-
-}
-
-export function behaviorContextGlobals() {
-  return {
-    Flow: [Flow, 'Flow'],
-  };
-}
-
-export function behaviorContextTypes() {
-  return {
-    Flow: {
-      children: {
-        conditional: {
-          type: 'bool',
-          label: 'If $1 then run $2.',
-          args: [
-            ['condition', {
-              type: 'condition',
-            }],
-            ['actions', {
-              type: 'actions',
-            }],
-          ],
-        },
-        parallel: {
-          type: 'void',
-          label: 'Run $1 in parallel.',
-          args: [
-            ['actions', {
-              type: 'actions',
-            }],
-          ],
-        },
-        serial: {
-          type: 'void',
-          label: 'Run $1 serially.',
-          args: [
-            ['actions', {
-              type: 'actions',
-            }],
-          ],
-        },
-      },
-    },
-  };
-}
-
--- a/packages/behavior/context/index.js
+++ b/packages/behavior/context/index.js
@ -1 +0,0 @@
-export {Context} from './context';
--- a/packages/behavior/context/timing.hooks.js
+++ b/packages/behavior/context/timing.hooks.js
@ -1,41 +0,0 @@
-import {TickingPromise} from '@avocado/core';
-
-class Timing {
-
-  static wait (duration) {
-    return new TickingPromise(
-      () => {},
-      (elapsed, resolve) => {
-        duration -= elapsed;
-        if (duration <= 0) {
-          resolve();
-        }
-      },
-    );
-  }
-
-}
-
-export function behaviorContextTypes() {
-  return {
-    Timing: {
-      children: {
-        wait: {
-          type: 'void',
-          label: 'Wait for $1 seconds.',
-          args: [
-            ['duration', {
-              type: 'number',
-            }],
-          ],
-        },
-      },
-    },
-  };
-}
-
-export function behaviorContextGlobals() {
-  return {
-    Timing: [Timing, 'Timing'],
-  };
-}
--- a/packages/behavior/context/utility.hooks.js
+++ b/packages/behavior/context/utility.hooks.js
@ -1,68 +0,0 @@
-import {merge as mergeObject} from '@avocado/core';
-
-class Utility {
-
-  static makeArray(...args) {
-    // No context!
-    args.pop();
-    return args;
-  };
-
-  static makeObject(...args) {
-    // No context!
-    args.pop();
-    const object = {};
-    while (args.length > 0) {
-      const key = args.shift();
-      const value = args.shift();
-      object[key] = value;
-    }
-    return object;
-  };
-
-  static log(...args) {
-    return console.log(...args);
-  }
-
-  static merge(...args) {
-    // No context!
-    args.pop();
-    return mergeObject(...args);
-  }
-
-}
-
-export function behaviorContextTypes() {
-  return {
-    Utility: {
-      children: {
-        makeArray: {
-          type: 'array',
-          label: 'Make array.',
-          args: [],
-        },
-        makeObject: {
-          type: 'object',
-          label: 'Make object.',
-          args: [],
-        },
-        log: {
-          type: 'void',
-          label: 'Log.',
-          args: [],
-        },
-        merge: {
-          type: 'object',
-          label: 'Merge objects.',
-          args: [],
-        },
-      },
-    },
-  };
-}
-
-export function behaviorContextGlobals() {
-  return {
-    Utility: [Utility, 'Utility'],
-  };
-}
--- a/packages/behavior/index.js
+++ b/packages/behavior/index.js
@ -1,10 +1,29 @@
-export {Context} from './context';
 export {
-  fromJSON as behaviorItemFromJSON,
-} from './item/registry';
+  default as Actions,
+} from './actions';
+
 export {
  buildCondition,
  buildInvoke,
-  buildTraversal,
+  buildExpression,
  buildValue,
 } from './builders';
+
+export {
+  default as compile,
+  compilers,
+} from './compile';
+
+export {
+  default as Context,
+  globals as contextGlobals,
+} from './context';
+
+export {
+  candidates,
+  description,
+  digraph,
+  fitsInto,
+  invertedDigraph,
+  types,
+} from './type';
--- a/packages/behavior/item/action.js
+++ b/packages/behavior/item/action.js
@ -1,12 +0,0 @@
-import {Traversal} from './traversal';
-
-export class Action extends Traversal {
-
-  toJSON() {
-    return {
-      ...super.toJSON(),
-      type: 'action',
-    };
-  }
-
-}
--- a/packages/behavior/item/actions.spec.js
+++ b/packages/behavior/item/actions.spec.js
@ -1,93 +0,0 @@
-import {expect} from 'chai';
-
-import {TickingPromise} from '@avocado/core';
-
-import {buildInvoke, buildTraversal, buildValue} from '../builders';
-import {Context} from '../context';
-import {Actions} from './actions';
-import './initialize'
-
-describe('behavior', () => {
-  describe('Actions', () => {
-    const context = new Context();
-    beforeEach(() => {
-      context.clear();
-    });
-    it('may resolve immediately', (done) => {
-      const actions = new Actions();
-      let total = 0;
-      const increment = () => total++;
-      context.add('increment', increment);
-      actions.fromJSON({
-        type: 'actions',
-        traversals: [
-          buildTraversal(['increment']),
-          buildTraversal(['increment']),
-          buildTraversal(['increment']),
-        ],
-      });
-      actions.on('actionsFinished', done);
-      actions.tick(context, 0);
-      expect(actions.index).to.equal(0);
-      expect(total).to.equal(3);
-    });
-    it('may defer', async () => {
-      const actions = new Actions();
-      let resolve;
-      const promise = new Promise((_) => resolve = _);
-      context.add('test', promise);
-      context.add('test2', new Promise(() => {}));
-      actions.fromJSON({
-        type: 'actions',
-        traversals: [
-          buildTraversal(['test']),
-          buildTraversal(['test2']),
-        ],
-      });
-      actions.tick(context, 0);
-      // Waiting?
-      expect(actions.index).to.equal(0);
-      resolve();
-      return promise.finally(() => {
-        // Waiting on next...
-        expect(actions.index).to.equal(1);
-      });
-    });
-    it('may defer with ticking', async () => {
-      const actions = new Actions();
-      let resolve;
-      let duration = 1;
-      const tickingPromise = new TickingPromise(
-        () => {},
-        (elapsed, resolve) => {
-          duration -= elapsed;
-          if (duration <= 0) {
-            resolve();
-          }
-        },
-      );
-      context.add('test', tickingPromise);
-      context.add('test2', new Promise(() => {}));
-      actions.fromJSON({
-        type: 'actions',
-        traversals: [
-          buildTraversal(['test']),
-          buildTraversal(['test2']),
-        ],
-      });
-      actions.tick(context, 0);
-      // Waiting?
-      expect(actions.index).to.equal(0);
-      actions.tick(context, 0.5);
-      expect(actions.index).to.equal(0);
-      actions.tick(context, 0.5);
-      // Still gotta be waiting...
-      expect(actions.index).to.equal(0);
-      return tickingPromise.finally(() => {
-        // Waiting on next...
-        expect(duration).to.equal(0);
-        expect(actions.index).to.equal(1);
-      });
-    });
-  });
-});
--- a/packages/behavior/item/collection.js
+++ b/packages/behavior/item/collection.js
@ -1,46 +0,0 @@
-import {fromJSON as behaviorItemFromJSON} from './registry';
-
-export function Collection(type) {
-  const plural = `${type}s`;
-  return class Collection {
-
-    constructor() {
-      this[plural] = [];
-    }
-
-    clone(other) {
-      if (0 === other[plural].length) {
-        return;
-      }
-      const Item = other[plural][0].constructor;
-      for (let i = 0; i < other[plural].length; ++i) {
-        this[plural][i] = new Item();
-        this[plural][i].clone(other[plural][i]);
-      }
-    }
-
-    createClone() {
-      const Items = this.constructor;
-      const items = new Items();
-      items.clone(this);
-      return items;
-    }
-
-    count() {
-      return this[plural].length;
-    }
-
-    fromJSON(json) {
-      this[plural] = [];
-      for (const item of json[plural]) {
-        this[plural].push(behaviorItemFromJSON(item));
-      }
-      return this;
-    }
-
-    toJSON() {
-      return this[plural].map((item) => item.toJSON());
-    }
-
-  };
-}
--- a/packages/behavior/item/condition.js
+++ b/packages/behavior/item/condition.js
@ -1,106 +0,0 @@
-import {fromJSON as behaviorItemFromJSON} from './registry';
-
-export class Condition {
-
-  constructor() {
-    this.operator = '';
-    this.operands = [];
-  }
-
-  check(context) {
-    return this.get(context);
-  }
-
-  clone(other) {
-    this.operator = other.operator;
-    this.operands = other.operands.map((operand) => operand.clone());
-  }
-
-  fromJSON(json) {
-    this.operator = json.operator;
-    this.operands = json.operands.map((operand) => {
-      return behaviorItemFromJSON(operand);
-    });
-    return this;
-  }
-
-  get(context) {
-    switch (this.operator) {
-      case 'is':
-        return this.operands[0].get(context) === this.operands[1].get(context);
-      case 'isnt':
-        return this.operands[0].get(context) !== this.operands[1].get(context);
-      case '>':
-        return this.operands[0].get(context) > this.operands[1].get(context);
-      case '>=':
-        return this.operands[0].get(context) >= this.operands[1].get(context);
-      case '<':
-        return this.operands[0].get(context) < this.operands[1].get(context);
-      case '<=':
-        return this.operands[0].get(context) <= this.operands[1].get(context);
-
-      case 'or':
-        if (0 === this.operands.length) {
-          return true;
-        }
-        for (const operand of this.operands) {
-          if (!!operand.get(context)) {
-            return true;
-          }
-        }
-        return false;
-
-      case 'and':
-        if (0 === this.operands.length) {
-          return true;
-        }
-        for (const operand of this.operands) {
-          if (!operand.get(context)) {
-            return false;
-          }
-        }
-        return true;
-
-      case 'contains':
-        if (this.operands.length < 2) {
-          return false;
-        }
-        const haystack = this.operands[0].get(context);
-        const needle = this.operands[1].get(context);
-        return -1 !== haystack.indexOf(needle);
-
-    }
-  }
-
-  operandCount() {
-    return this.operands.length;
-  }
-
-  operand(index) {
-    return this.operands[index];
-  }
-
-  operands() {
-    return this.operands;
-  }
-
-  operator() {
-    return this.operator;
-  }
-
-  setOperand(index, operand) {
-    this.operands[index] = operand;
-  }
-
-  setOperator(operator) {
-    this.operator = operator;
-  }
-
-  toJSON() {
-    return {
-      type: 'condition',
-      operator: this.operator,
-      operands: this.operands.map((operand) => operand.toJSON()),
-    };
-  }
-}
--- a/packages/behavior/item/condition.spec.js
+++ b/packages/behavior/item/condition.spec.js
@ -1,109 +0,0 @@
-import {expect} from 'chai';
-
-import {Condition} from './condition';
-import {Literal} from './literal';
-import {deregister, register} from './registry';
-
-describe('behavior', () => {
-  describe('condition', () => {
-    it('can do binary compares', () => {
-      const condition = new Condition();
-      condition.setOperand(0, new Literal().fromJSON({
-        type: 'literal',
-        value: 500,
-      }));
-      condition.setOperand(1, new Literal().fromJSON({
-        type: 'literal',
-        value: 420,
-      }));
-      // Greater than.
-      condition.setOperator('>');
-      expect(condition.check()).to.be.true;
-      // Less than.
-      condition.setOperator('<');
-      expect(condition.check()).to.be.false;
-      // Greater than or equal.
-      condition.setOperator('>=');
-      expect(condition.check()).to.be.true;
-      // Less than or equal.
-      condition.setOperator('<=');
-      expect(condition.check()).to.be.false;
-      // Is.
-      condition.setOperator('is');
-      expect(condition.check()).to.be.false;
-      // Is not.
-      condition.setOperator('isnt');
-      expect(condition.check()).to.be.true;
-    });
-    it('can do varnary compares', () => {
-      const condition = new Condition();
-      condition.setOperand(0, new Literal().fromJSON({
-        type: 'literal',
-        value: true,
-      }));
-      condition.setOperand(1, new Literal().fromJSON({
-        type: 'literal',
-        value: true,
-      }));
-      condition.setOperand(2, new Literal().fromJSON({
-        type: 'literal',
-        value: false,
-      }));
-      // AND, mixed.
-      condition.setOperator('and');
-      expect(condition.check()).to.be.false;
-      // OR, mixed.
-      condition.setOperator('or');
-      expect(condition.check()).to.be.true;
-      // OR, all true.
-      condition.setOperand(2, new Literal().fromJSON({
-        type: 'literal',
-        value: true,
-      }));
-      expect(condition.check()).to.be.true;
-      // AND, all true.
-      condition.setOperator('and');
-      expect(condition.check()).to.be.true;
-      // AND, all false.
-      for (const i of [0, 1, 2]) {
-        condition.setOperand(i, new Literal().fromJSON({
-          type: 'literal',
-          value: false,
-        }));
-      }
-      expect(condition.check()).to.be.false;
-      // OR, all false.
-      condition.setOperator('or');
-      expect(condition.check()).to.be.false;
-    });
-    describe('JSON', () => {
-      beforeEach(() => {
-        register(Literal);
-      });
-      afterEach(() => {
-        deregister(Literal);
-      });
-      it('can instantiate operands', () => {
-        const condition = new Condition();
-        // Greater than.
-        condition.fromJSON({
-          operator: '>',
-          operands: [
-            {
-              type: 'literal',
-              value: 500,
-            },
-            {
-              type: 'literal',
-              value: 420,
-            },
-          ],
-        });
-        expect(condition.check()).to.be.true;
-        // Less than.
-        condition.setOperator('<');
-        expect(condition.check()).to.be.false;
-      });
-    });
-  });
-});
--- a/packages/behavior/item/conditions.js
+++ b/packages/behavior/item/conditions.js
@ -1,14 +0,0 @@
-import {Collection} from './collection';
-
-export class Conditions extends Collection('condition') {
-
-  check(context) {
-    for (condition of this.conditions) {
-      if (!this.conditions[index].check(context)) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-}
--- a/packages/behavior/item/items.hooks.js
+++ b/packages/behavior/item/items.hooks.js
@ -1,23 +0,0 @@
-import {Action} from './action';
-import {Actions} from './actions';
-import {Condition} from './condition';
-import {Conditions} from './conditions';
-import {Literal} from './literal';
-import {Routine} from './routine';
-import {Routines} from './routines';
-import {Traversal} from './traversal';
-import {Traversals} from './traversals';
-
-export function avocadoBehaviorItems() {
-  return {
-    action: Action,
-    actions: Actions,
-    condition: Condition,
-    conditions: Conditions,
-    literal: Literal,
-    routine: Routine,
-    routines: Routines,
-    traversal: Traversal,
-    traversals: Traversals,
-  };
-}
--- a/packages/behavior/item/literal.js
+++ b/packages/behavior/item/literal.js
@ -1,30 +0,0 @@
-export class Literal {
-
-  constructor() {
-    this.value = null;
-  }
-
-  clone(other) {
-    this.value = other.value;
-  }
-
-  fromJSON(json) {
-    this.value = json.value;
-    return this;
-  }
-
-  get(context) {
-    return this.value;
-  }
-
-  set(value) {
-    this.value = value;
-  }
-
-  toJSON() {
-    return {
-      type: 'literal',
-      value: this.value,
-    }
-  }
-}
--- a/packages/behavior/item/literal.spec.js
+++ b/packages/behavior/item/literal.spec.js
@ -1,22 +0,0 @@
-import {expect} from 'chai';
-
-import {Literal} from './literal';
-
-describe('behavior', () => {
-  describe('Literal', () => {
-    let literal = undefined;
-    beforeEach(() => {
-      literal = new Literal();
-      literal.fromJSON({
-        value: 69,
-      });
-    });
-    it('can access literals', () => {
-      expect(literal.get()).to.equal(69);
-    });
-    it('can modify literals', () => {
-      literal.set(420);
-      expect(literal.get()).to.equal(420);
-    });
-  });
-});
--- a/packages/behavior/item/registry.js
+++ b/packages/behavior/item/registry.js
@ -1,26 +0,0 @@
-import {invokeHookFlat} from 'scwp';
-
-let _behaviorItems;
-
-export function fromJSON({type, ...json}) {
-  const items = behaviorItems();
-  const Class = items[type];
-  if (!Class) {
-    throw new TypeError(`There is no class for the behavior item "${type}"`);
-  }
-  return (new Class()).fromJSON(json);
-}
-
-function behaviorItems() {
-  if (!_behaviorItems) {
-    _behaviorItems = {};
-    const itemsLists = invokeHookFlat('avocadoBehaviorItems');
-    for (let i = 0; i < itemsLists.length; i++) {
-      _behaviorItems = {
-        ..._behaviorItems,
-        ...itemsLists[i],
-      };
-    }
-  }
-  return _behaviorItems;
-}
--- a/packages/behavior/item/routine.js
+++ b/packages/behavior/item/routine.js
@ -1,29 +0,0 @@
-import {Actions} from './actions';
-
-export class Routine {
-
-  constructor() {
-    this.actions = new Actions();
-  }
-
-  clone(other) {
-    this.actions = other.actions.clone();
-  }
-
-  fromJSON(json) {
-    this.actions.fromJSON(json.routine);
-    return this;
-  }
-
-  tick(context, elapsed) {
-    this.actions.tick(context, elapsed);
-  }
-
-  toJSON() {
-    return {
-      type: 'routine',
-      actions: this.actions.toJSON(),
-    }
-  }
-
-}
--- a/packages/behavior/item/routines.js
+++ b/packages/behavior/item/routines.js
@ -1,45 +0,0 @@
-import {Routine} from './routine';
-
-export class Routines {
-
-  constructor() {
-    this.routines = {};
-  }
-
-  *[Symbol.iterator]() {
-    for (const index in this.routines) {
-      const routine = this.routines[index];
-      yield routine;
-    }
-  }
-
-  clone(other) {
-    for (const i in other.routines) {
-      const routine = other.routines[i];
-      this.routines[i] = routine.clone();
-    }
-  }
-
-  fromJSON(json) {
-    for (const i in json.routines) {
-      const routineJSON = json.routines[i];
-      this.routines[i] = (new Routine()).fromJSON(routineJSON);
-    }
-    return this;
-  }
-
-  routine(index) {
-    return this.routines[index];
-  }
-
-  toJSON() {
-    const routines = {};
-    for (const i in this.routines) {
-      routines[i] = this.routines[i].toJSON();
-    }
-    return {
-      type: 'routines',
-      routines,
-    };
-  }
-}
--- a/packages/behavior/item/traversal.js
+++ b/packages/behavior/item/traversal.js
@ -1,80 +0,0 @@
-import {fromJSON as behaviorItemFromJSON} from './registry';
-
-export class Traversal {
-
-  constructor(json) {
-    this.steps = [];
-    this.value = undefined;
-    if (json) {
-      this.fromJSON(json);
-    }
-  }
-
-  clone(other) {
-    this.steps = other.steps.map((step) => {
-      switch (step.type) {
-        case 'key':
-          return step;
-        case 'invoke':
-          return {
-            type: 'invoke',
-            args: step.args.map((arg, index) => {
-              const Item = arg.constructor;
-              const item = new Item();
-              item.clone(arg);
-              return item;
-            }),
-          };
-      }
-    });
-    if (other.value) {
-      this.value = other.value.clone();
-    }
-  }
-
-  fromJSON(json) {
-    this.steps = json.steps.map((step) => {
-      switch (step.type) {
-        case 'key':
-          return step;
-        case 'invoke':
-          return {
-            type: 'invoke',
-            args: step.args.map((arg) => behaviorItemFromJSON(arg)),
-          };
-      }
-    });
-    if (json.value) {
-      this.value = behaviorItemFromJSON(json.value);
-    }
-    return this;
-  }
-
-  get(context) {
-    return this.traverse(context);
-  }
-
-  traverse(context) {
-    if (context) {
-      return context.traverse(this);
-    }
-  }
-
-  toJSON() {
-    return {
-      type: 'traversal',
-      steps: this.steps.map((step) => {
-        switch (step.type) {
-          case 'key':
-            return step;
-          case 'invoke':
-            return {
-              type: 'invoke',
-              args: step.args.map((arg) => arg.toJSON()),
-            };
-        }
-      }),
-      value: this.value ? this.value.toJSON() : undefined,
-    };
-  }
-}
--- a/packages/behavior/item/traversals.js
+++ b/packages/behavior/item/traversals.js
@ -1,21 +0,0 @@
-import {TickingPromise} from '@avocado/core';
-
-import {Collection} from './collection';
-import {Traversal} from './traversal';
-
-export class Traversals extends Collection('traversal') {
-
-  parallel(context) {
-    const results = this.traversals.map((traversal) => {
-      return traversal.traverse(context);
-    });
-    // Early out if no promises.
-    if (!results.reduce((has, result) => {
-      return has || result instanceof Promise;
-    }, false)) {
-      return results;
-    }
-    return TickingPromise.all(results);
-  }
-
-}
--- a/packages/behavior/traits/behaved.trait.js
+++ b/packages/behavior/traits/behaved.trait.js
@ -1,8 +1,9 @@
-import {compose, flatten} from '@avocado/core';
+import {compose, flatten, mapObject} from '@avocado/core';
 import {StateProperty, Trait} from '@avocado/entity';

-import {Context} from '../context';
-import {Routines} from '../item/routines';
+import Actions from '../actions';
+import compile from '../compile';
+import Context from '../context';

 const decorate = compose(
  StateProperty('currentRoutine', {
@ -13,7 +14,7 @@ const decorate = compose(

 export default class Behaved extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      context: {
        type: 'context',
@ -67,7 +68,10 @@ export default class Behaved extends decorate(Trait) {
      entity: [this.entity, 'entity'],
    });
    this._currentRoutine = undefined;
-    this._routines = (new Routines()).fromJSON(this.params.routines);
+    this._routines = mapObject(
+      this.params.routines,
+      (routine) => new Actions(compile(routine))
+    );
    this.updateCurrentRoutine(this.state.currentRoutine);
  }

@ -82,7 +86,7 @@ export default class Behaved extends decorate(Trait) {
  }

  updateCurrentRoutine(currentRoutine) {
-    this._currentRoutine = this._routines.routine(currentRoutine);
+    this._currentRoutine = this._routines[currentRoutine];
  }

  listeners() {
--- a/packages/behavior/type.js
+++ b/packages/behavior/type.js
@ -0,0 +1,108 @@
+import {arrayUnique, flatten, mapObject} from '@avocado/core';
+import memoize from 'lodash.memoize';
+import {invokeHookFlat, registerHooks} from 'scwp';
+
+export const types = memoize(() => {
+  return invokeHookFlat('behaviorTypes')
+    .reduce((r, results) => ({
+      ...r,
+      ...results,
+    }), {});
+});
+
+function typeDigraph(type, marked = {}) {
+  const allTypes = types();
+  if (marked[type] || !allTypes[type]) {
+    marked[type] = true;
+    return [];
+  }
+  const description = description(type, undefined);
+  const subtypes = Object.keys(
+    Object.values(description.children)
+      .reduce((r, {type: childType}) => ({
+        ...r,
+        [childType]: true,
+      }), {})
+  );
+  subtypes.forEach((type) => marked[type] = true);
+  return arrayUnique(flatten(subtypes.map((type) => typeDigraph(type, marked))).concat(subtypes));
+}
+
+export const digraph = memoize(() => {
+  return Object.keys(allTypes())
+    .reduce((r, type) => ({
+      ...r,
+      [type]: typeDigraph(type),
+    }), {});
+});
+
+export const invertedDigraph = memoize(() => {
+  const digraph = digraph();
+  let inverted = {};
+  const fromTypes = Object.keys(digraph);
+  for (let i = 0; i < fromTypes.length; i++) {
+    const fromType = fromTypes[i];
+    const toTypes = digraph[fromType];
+    for (let j = 0; j < toTypes.length; j++) {
+      const toType = toTypes[j];
+      inverted[toType] = (inverted[toType] || {});
+      inverted[toType][fromType] = true;
+    }
+  }
+  inverted = mapObject(inverted, (types) => Object.keys(types));
+  inverted = mapObject(inverted, (types) => (
+    arrayUnique(flatten(types.map((type) => (inverted[type] || []).concat(type))))
+  ));
+  return inverted;
+});
+
+export const candidates = (description, type) => {
+  const inverted = invertedDigraph();
+  const types = (inverted[type] || []).concat(type);
+  const {children} = description;
+  return 'any' === type
+    ? Object.keys(children)
+    : Object.entries(children)
+      .reduce((r, [key, {type}]) => (
+        r.concat(
+          types.some((candidate) => typeFits(candidate, type))
+            ? [key]
+            : []
+        )
+      ), []);
+};
+
+export function description(type, instance) {
+  const allTypes = types();
+  const defaults = {
+    children: {},
+    type,
+  };
+  if (!allTypes[type]) {
+    return {
+      ...defaults,
+      type: 'undefined',
+    };
+  }
+  return {
+    ...defaults,
+    ...('function' === typeof allTypes[type] ? allTypes[type](variable) : allTypes[type])
+  };
+}
+
+export function fitsInto(candidate, reference) {
+  if ('any' === reference) {
+    return true;
+  }
+  return -1 !== reference.split('|').map((type) => type.trim()).indexOf(candidate);
+}
+
+registerHooks({
+  autoreg$accept: (type, M) => {
+    if ('hooks' === type && 'behaviorTypes' in M) {
+      allTypes.cache.clear();
+      digraph.cache.clear();
+      invertedDigraph.cache.clear();
+    }
+  },
+}, module.id);
--- a/packages/behavior/types.hooks.js
+++ b/packages/behavior/types.hooks.js
@ -0,0 +1,114 @@
+import Flow from './types/flow';
+import Timing from './types/timing';
+import Utility from './types/utility';
+
+export function behaviorContextGlobals() {
+  return {
+    Flow: [Flow, 'Flow'],
+    Timing: [Timing, 'Timing'],
+    Utility: [Utility, 'Utility'],
+  };
+}
+
+export function behaviorTypes() {
+  return {
+    bool: {
+      defaultLiteral: true,
+    },
+    context: {
+      children: {
+        add: {
+          type: 'void',
+          label: 'Add $2 as $1.',
+          args: [
+            ['key', {
+              type: 'string',
+            }],
+            ['value', {
+              type: 'any',
+            }],
+          ],
+        },
+      },
+    },
+    Flow: {
+      children: {
+        conditional: {
+          type: 'bool',
+          label: 'If $1 then run $2.',
+          args: [
+            ['condition', {
+              type: 'condition',
+            }],
+            ['actions', {
+              type: 'actions',
+            }],
+          ],
+        },
+        parallel: {
+          type: 'void',
+          label: 'Run $1 in parallel.',
+          args: [
+            ['actions', {
+              type: 'actions',
+            }],
+          ],
+        },
+        serial: {
+          type: 'void',
+          label: 'Run $1 serially.',
+          args: [
+            ['actions', {
+              type: 'actions',
+            }],
+          ],
+        },
+      },
+    },
+    number: {
+      defaultLiteral: 0,
+    },
+    stream: {},
+    string: {
+      defaultLiteral: '',
+    },
+    Timing: {
+      children: {
+        wait: {
+          type: 'void',
+          label: 'Wait for $1 seconds.',
+          args: [
+            ['duration', {
+              type: 'number',
+            }],
+          ],
+        },
+      },
+    },
+    Utility: {
+      children: {
+        makeArray: {
+          type: 'array',
+          label: 'Make array.',
+          args: [],
+        },
+        makeObject: {
+          type: 'object',
+          label: 'Make object.',
+          args: [],
+        },
+        log: {
+          type: 'void',
+          label: 'Log.',
+          args: [],
+        },
+        merge: {
+          type: 'object',
+          label: 'Merge objects.',
+          args: [],
+        },
+      },
+    },
+    void: {},
+  };
+}
--- a/packages/behavior/types/flow.js
+++ b/packages/behavior/types/flow.js
@ -0,0 +1,19 @@
+import Actions from '../actions';
+
+export default class Flow {
+
+  static conditional(condition, expressions, context) {
+    if (condition.get(context)) {
+      return (new Actions(expressions)).serial(context);
+    }
+  };
+
+  static parallel(expressions, context) {
+    return (new Actions(expressions)).parallel(context);
+  }
+
+  static serial(expressions, context) {
+    return (new Actions(expressions)).serial(context);
+  }
+
+}
--- a/packages/behavior/types/timing.js
+++ b/packages/behavior/types/timing.js
@ -0,0 +1,17 @@
+import {TickingPromise} from '@avocado/core';
+
+export default class Timing {
+
+  static wait (duration) {
+    return new TickingPromise(
+      () => {},
+      (elapsed, resolve) => {
+        duration -= elapsed;
+        if (duration <= 0) {
+          resolve();
+        }
+      },
+    );
+  }
+
+}
--- a/packages/behavior/types/utility.js
+++ b/packages/behavior/types/utility.js
@ -0,0 +1,33 @@
+import {merge as mergeObject} from '@avocado/core';
+
+export default class Utility {
+
+  static makeArray(...args) {
+    // No context!
+    args.pop();
+    return args;
+  };
+
+  static makeObject(...args) {
+    // No context!
+    args.pop();
+    const object = {};
+    while (args.length > 0) {
+      const key = args.shift();
+      const value = args.shift();
+      object[key] = value;
+    }
+    return object;
+  };
+
+  static log(...args) {
+    return console.log(...args);
+  }
+
+  static merge(...args) {
+    // No context!
+    args.pop();
+    return mergeObject(...args);
+  }
+
+}
--- a/packages/entity/entity.synchronized.js
+++ b/packages/entity/entity.synchronized.js
@ -243,11 +243,12 @@ export default class Entity extends decorate(Resource) {
        promises.push(this._traitsFlat[i].hydrate());
      }
      this._hydrationPromise = Promise.all(promises);
-    }
-    return this._hydrationPromise.then(() => {
+      this._hydrationPromise.then(() => {
        this.tick(0);
      });
    }
+    return this._hydrationPromise;
+  }

  invokeHook(hook, ...args) {
    const results = {};
--- a/packages/entity/index.hooks.js
+++ b/packages/entity/index.hooks.js
@ -1,4 +1,4 @@
-export function behaviorContextTypes() {
+export function behaviorTypes() {
  return {
    entity: (entity) => {
      const {allTraits} = require('./trait/registrar');
@ -20,7 +20,7 @@ export function behaviorContextTypes() {
      };
      return Traits
        .reduce((r, T) => ({
-          ...r, children: {...r.children, ...T.behaviorContextTypes(), ...T.describeState()},
+          ...r, children: {...r.children, ...T.behaviorTypes(), ...T.describeState()},
        }), core);
    },
  };
--- a/packages/entity/list/index.js
+++ b/packages/entity/list/index.js
@ -71,6 +71,7 @@ export class EntityList extends decorate(class {}) {
    if (AVOCADO_SERVER) {
      this._informedEntities.set(entity, []);
    }
+    entity.hydrate();
    entity.attachToList(this);
    entity.once('destroy', () => {
      this.removeEntity(entity);
--- a/packages/entity/trait/index.js
+++ b/packages/entity/trait/index.js
@ -38,7 +38,7 @@ export class Trait extends decorate(class {}) {
    this._fastDirtyCheck = false;
  }

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {};
  }

--- a/packages/entity/traits/alive.trait.js
+++ b/packages/entity/traits/alive.trait.js
@ -1,8 +1,9 @@
 import {
-  behaviorItemFromJSON,
+  Actions,
  buildCondition,
  buildInvoke,
-  buildTraversal,
+  buildExpression,
+  compile,
  Context,
 } from '@avocado/behavior';
 import {compose} from '@avocado/core';
@ -25,7 +26,7 @@ const decorate = compose(

 export default class Alive extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      deathSound: {
        type: 'string',
@ -40,7 +41,7 @@ export default class Alive extends decorate(Trait) {

  static defaultParams() {
    const playDeathSound = buildInvoke(['entity', 'playSound'], [
-      buildTraversal(['entity', 'deathSound']),
+      buildExpression(['entity', 'deathSound']),
    ]);
    const squeeze = buildInvoke(['entity', 'transition'], [
      {
@ -51,13 +52,13 @@ export default class Alive extends decorate(Trait) {
      0.2,
    ]);
    const isLifeGone = buildCondition('<=', [
-      buildTraversal(['entity', 'life']),
+      buildExpression(['entity', 'life']),
      0,
    ]);
    return {
      deathActions: {
-        type: 'actions',
-        traversals: [
+        type: 'expressions',
+        expressions: [
          playDeathSound,
          squeeze,
        ],
@ -118,8 +119,8 @@ export default class Alive extends decorate(Trait) {
    this._context = new Context({
      entity: [this.entity, 'entity'],
    });
-    this._deathActions = behaviorItemFromJSON(this.params.deathActions);
-    this._deathCondition = behaviorItemFromJSON(this.params.deathCondition);
+    this._deathActions = new Actions(compile(this.params.deathActions));
+    this._deathCondition = compile(this.params.deathCondition);
  }

  destroy() {
@ -183,13 +184,13 @@ export default class Alive extends decorate(Trait) {
          return;
        }
        this.entity.isDying = true;
-        const dyingTickingPromise = this._deathActions.tickingPromise(this._context);
-        this.entity.addTickingPromise(dyingTickingPromise).then(() => {
-          const diedPromises = this.entity.invokeHookFlat('died');
-          Promise.all(diedPromises).then(() => {
+        return this.entity.addTickingPromise(this._deathActions.tickingPromise(this._context))
+          .then(() => (
+            Promise.all(this.entity.invokeHookFlat('died'))
+              .then(() => {
                this.entity.destroy();
-          });
-        });
+              })
+          ));
      },

    };
@ -197,7 +198,7 @@ export default class Alive extends decorate(Trait) {

  tick(elapsed) {
    if (AVOCADO_SERVER) {
-      if (!this.entity.isDying && this._deathCondition.check(this._context)) {
+      if (!this.entity.isDying && this._deathCondition(this._context)) {
        this.entity.forceDeath();
      }
    }
--- a/packages/entity/traits/existent.trait.js
+++ b/packages/entity/traits/existent.trait.js
@ -10,7 +10,7 @@ const decorate = compose(

 export default class Existent extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      destroy: {
        type: 'void',
--- a/packages/entity/traits/listed.trait.js
+++ b/packages/entity/traits/listed.trait.js
@ -4,7 +4,7 @@ import {Trait} from '../trait';

 export default class Listed extends Trait {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      detachFromList: {
        type: 'void',
--- a/packages/entity/traits/mobile.trait.js
+++ b/packages/entity/traits/mobile.trait.js
@ -10,7 +10,7 @@ const decorate = compose(

 export default class Mobile extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      moveFor: {
        type: 'void',
--- a/packages/entity/traits/positioned.trait.js
+++ b/packages/entity/traits/positioned.trait.js
@ -17,7 +17,7 @@ const decorate = compose(
 // < 16768 will pack into 1 short per axe and give +/- 0.25 precision.
 export default class Positioned extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      position: {
        type: 'vector',
--- a/packages/entity/traits/spawner.trait.js
+++ b/packages/entity/traits/spawner.trait.js
@ -13,7 +13,7 @@ const decorate = compose(

 export default class Spawner extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      killAllChildren: {
        type: 'void',
--- a/packages/graphics/traits/visible.trait.js
+++ b/packages/graphics/traits/visible.trait.js
@ -1,5 +1,3 @@
-import * as I from 'immutable';
-
 import {compose, Property} from '@avocado/core';
 import {StateProperty, Trait} from '@avocado/entity';
 import {Rectangle, Vector} from '@avocado/math';
@ -30,7 +28,7 @@ const decorate = compose(

 export default class Visible extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      updateVisibleBoundingBox: {
        advanced: true,
--- a/packages/math/index.hooks.js
+++ b/packages/math/index.hooks.js
@ -6,7 +6,7 @@ export function behaviorContextGlobals() {
  };
 }

-export function behaviorContextTypes() {
+export function behaviorTypes() {
  return {
    Math: (Math) => ({
      children: {
--- a/packages/math/vector/index.hooks.js
+++ b/packages/math/vector/index.hooks.js
@ -1,4 +1,4 @@
-export function behaviorContextTypes() {
+export function behaviorTypes() {
  return {
    vector: {
      defaultLiteral: [0, 0],
--- a/packages/math/vector/index.js
+++ b/packages/math/vector/index.js
@ -409,7 +409,7 @@ export class Range extends MathRange {

 }

-export function behaviorContextTypes() {
+export function behaviorTypes() {
  return {
    type: 'Vector',
    children: {
--- a/packages/physics/traits/collider.trait.js
+++ b/packages/physics/traits/collider.trait.js
@ -1,4 +1,4 @@
-import {behaviorItemFromJSON, Context} from '@avocado/behavior';
+import {Actions, compile, Context} from '@avocado/behavior';
 import {compose, TickingPromise} from '@avocado/core';
 import {StateProperty, Trait} from '@avocado/entity';
 import {Rectangle, Vector} from '@avocado/math';
@ -10,7 +10,7 @@ const decorate = compose(

 export default class Collider extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      collidesWith: {
        advanced: true,
@ -61,8 +61,14 @@ export default class Collider extends decorate(Trait) {
      collidesWithGroups: [
        'default',
      ],
-      collisionEndActions: undefined,
-      collisionStartActions: undefined,
+      collisionEndActions: {
+        type: 'expressions',
+        expressions: [],
+      },
+      collisionStartActions: {
+        type: 'expressions',
+        expressions: [],
+      },
      collisionGroup: 'default',
      isSensor: false,
    }
@ -123,22 +129,24 @@ export default class Collider extends decorate(Trait) {

  constructor(entity, params, state) {
    super(entity, params, state);
-    this._collidesWithGroups = this.params.collidesWithGroups;
-    if (this.params.collisionEndActions) {
-      this._collisionEndActions = behaviorItemFromJSON(
-        this.params.collisionEndActions,
-      );
-    }
-    if (this.params.collisionStartActions) {
-      this._collisionStartActions = behaviorItemFromJSON(
-        this.params.collisionStartActions,
-      );
-    }
-    this._collisionGroup = this.params.collisionGroup;
-    this._collisionTickingPromises = [];
+    const {
+      collidesWithGroups,
+      collisionEndActions,
+      collisionGroup,
+      collisionStartActions,
+      isSensor,
+    } = this.params;
+    this._collidesWithGroups = collidesWithGroups;
+    this._collisionEndActions = collisionEndActions.length > 0
+      ? new Actions(compile(collisionEndActions))
+      : undefined;
+    this._collisionStartActions = collisionStartActions.length > 0
+      ? new Actions(compile(collisionStartActions))
+      : undefined;
+    this._collisionGroup = collisionGroup;
    this._doesNotCollideWith = [];
    this._isCollidingWith = [];
-    this._isSensor = this.params.isSensor;
+    this._isSensor = isSensor;
  }

  destroy() {
@ -214,8 +222,7 @@ export default class Collider extends decorate(Trait) {
      entity: [this.entity, 'entity'],
      other: [this.entity, 'entity'],
    });
-    const tickingPromise = actions.tickingPromise(context);
-    this._collisionTickingPromises.push(tickingPromise);
+    this.entity.addTickingPromise(actions.tickingPromise(context));
  }

  releaseAllCollisions() {
@ -243,10 +250,7 @@ export default class Collider extends decorate(Trait) {
        if (-1 !== index) {
          this._isCollidingWith.splice(index, 1);
          if (this._collisionEndActions) {
-            this.pushCollisionTickingPromise(
-              this._collisionEndActions,
-              other
-            );
+            this.pushCollisionTickingPromise(this._collisionEndActions, other);
          }
        }
      },
@ -256,10 +260,7 @@ export default class Collider extends decorate(Trait) {
        if (-1 === index) {
          this._isCollidingWith.push(other);
          if (this._collisionStartActions) {
-            this.pushCollisionTickingPromise(
-              this._collisionStartActions,
-              other
-            );
+            this.pushCollisionTickingPromise(this._collisionStartActions, other);
          }
        }
      },
@ -306,9 +307,6 @@ export default class Collider extends decorate(Trait) {

  tick(elapsed) {
    if (AVOCADO_SERVER) {
-      for (let i = 0; i < this._collisionTickingPromises.length; ++i) {
-        this._collisionTickingPromises[i].tick(elapsed);
-      }
      this.checkActiveCollision();
    }
  }
--- a/packages/physics/traits/emitted.trait.js
+++ b/packages/physics/traits/emitted.trait.js
@ -8,7 +8,7 @@ const decorate = compose(

 export default class Emitted extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      particle: {
        type: 'particle',
--- a/packages/physics/traits/emitter.trait.js
+++ b/packages/physics/traits/emitter.trait.js
@ -14,7 +14,7 @@ const decorate = compose(

 export default class Emitter extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      emitParticleEntity: {
        cycle: true,
--- a/packages/physics/traits/physical.trait.js
+++ b/packages/physics/traits/physical.trait.js
@ -12,7 +12,7 @@ const decorate = compose(

 export default class Physical extends decorate(Trait) {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      applyForce: {
        type: 'void',
--- a/packages/sound/traits/audible.trait.js
+++ b/packages/sound/traits/audible.trait.js
@ -4,7 +4,7 @@ import {Sound} from '..';

 export default class Audible extends Trait {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      hasSound: {
        type: 'bool',
--- a/packages/topdown/index.hooks.js
+++ b/packages/topdown/index.hooks.js
@ -1,4 +1,4 @@
-export function behaviorContextTypes() {
+export function behaviorTypes() {
  return {
    layer: (layer) => {
      return {
--- a/packages/topdown/traits/layered.trait.js
+++ b/packages/topdown/traits/layered.trait.js
@ -3,7 +3,7 @@ import {Vector} from '@avocado/math';

 export default class Layered extends Trait {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      layer: {
        type: 'layer',
--- a/packages/topdown/traits/roomed.trait.js
+++ b/packages/topdown/traits/roomed.trait.js
@ -2,7 +2,7 @@ import {Trait} from '@avocado/entity';

 export default class Roomed extends Trait {

-  static behaviorContextTypes() {
+  static behaviorTypes() {
    return {
      detachFromRoom: {
        type: 'void',