diff --git a/src/app/app.ts b/src/app/app.ts
index bc12fb33..9ede4b1d 100644
--- a/src/app/app.ts
+++ b/src/app/app.ts
@@ -1,10 +1,10 @@
 import { DataModel } from '../model/DataModel'
 import { TreeView } from '../view/TreeView'
 import { SourceView } from '../view/SourceView'
-import { PredicateSchema } from '../schemas/PredicateSchema'
+import { ConditionSchema } from '../schemas/ConditionSchema'
 import { SandboxSchema } from '../schemas/SandboxSchema'
 
-const predicateModel = new DataModel(PredicateSchema)
+const predicateModel = new DataModel(ConditionSchema)
 const sandboxModel = new DataModel(SandboxSchema)
 
 let model = predicateModel
diff --git a/src/nodes/AbstractNode.ts b/src/nodes/AbstractNode.ts
index 9d535144..9f87a772 100644
--- a/src/nodes/AbstractNode.ts
+++ b/src/nodes/AbstractNode.ts
@@ -69,7 +69,7 @@ export abstract class AbstractNode<T> implements INode<T> {
 
   transform(path: Path, value: T) {
     if (!this.enabled(path)) return undefined
-    if (this.force()) value = this.default(value)!
+    if (value === undefined && this.force()) value = this.default(value)!
     return this.transformMod(value)
   }
 
diff --git a/src/nodes/ReferenceNode.ts b/src/nodes/ReferenceNode.ts
new file mode 100644
index 00000000..3b902922
--- /dev/null
+++ b/src/nodes/ReferenceNode.ts
@@ -0,0 +1,33 @@
+import { AbstractNode, NodeChildren, NodeMods, RenderOptions, INode } from './AbstractNode'
+import { TreeView } from '../view/TreeView'
+import { Path } from '../model/Path'
+import { SchemaRegistry } from '../schemas/SchemaRegistry'
+
+export class ReferenceNode extends AbstractNode<any> {
+  protected reference: string
+
+  constructor(reference: string, mods?: NodeMods<any>) {
+    super(mods)
+    this.reference = reference
+  }
+
+  get(): INode<any> {
+    return SchemaRegistry.get(this.reference)
+  }
+
+  default(value?: any) {
+    return this.get().default(value)
+  }
+
+  transform(path: Path, value: any) {
+    return this.get().transform(path, value)
+  }
+
+  render(path: Path, value: any, view: TreeView, options?: RenderOptions) {
+    return this.get().render(path, value, view, options)
+  }
+
+  renderRaw(path: Path, value: any, view: TreeView, options?: RenderOptions) {
+    return this.get().renderRaw(path, value, view, options)
+  }
+}
diff --git a/src/schemas/Collections.ts b/src/schemas/Collections.ts
new file mode 100644
index 00000000..c4789340
--- /dev/null
+++ b/src/schemas/Collections.ts
@@ -0,0 +1,59 @@
+export const conditions = [
+  'alternative',
+  'requirements',
+  'inverted',
+  'reference',
+  'entity_properties',
+  'block_state_property',
+  'match_tool',
+  'damage_source_properties',
+  'location_check',
+  'weather_check',
+  'time_check',
+  'entity_scores',
+  'random_chance',
+  'random_chance_with_looting',
+  'table_bonus',
+  'killed_by_player',
+  'survives_explosion'
+]
+
+export const enchantments = [
+  'aqua_affinity',
+  'bane_of_arthropods',
+  'blast_protection',
+  'channeling',
+  'binding_curse',
+  'vanishing_curse',
+  'depth_strider',
+  'efficiency',
+  'feather_falling',
+  'fire_aspect',
+  'fire_protection',
+  'flame',
+  'fortune',
+  'frost_walker',
+  'impaling',
+  'infinity',
+  'knockback',
+  'looting',
+  'loyalty',
+  'luck_of_the_sea',
+  'lure',
+  'mending',
+  'multishot',
+  'piercing',
+  'power',
+  'projectile_protection',
+  'protection',
+  'punch',
+  'quick_charge',
+  'respiration',
+  'riptide',
+  'sharpness',
+  'silk_touch',
+  'smite',
+  'sweeping',
+  'thorns',
+  'unbreaking'
+]
diff --git a/src/schemas/PredicateSchema.ts b/src/schemas/ConditionSchema.ts
similarity index 64%
rename from src/schemas/PredicateSchema.ts
rename to src/schemas/ConditionSchema.ts
index 41c2318e..7593a672 100644
--- a/src/schemas/PredicateSchema.ts
+++ b/src/schemas/ConditionSchema.ts
@@ -7,76 +7,20 @@ import { ListNode } from '../nodes/ListNode';
 import { RangeNode } from '../nodes/custom/RangeNode';
 import { MapNode } from '../nodes/MapNode';
 import { StringNode } from '../nodes/StringNode';
-import { INode } from '../nodes/AbstractNode';
+import { ReferenceNode } from '../nodes/ReferenceNode';
+import { SchemaRegistry } from './SchemaRegistry';
 
-const conditions = [
-  'alternative',
-  'requirements',
-  'inverted',
-  'reference',
-  'entity_properties',
-  'block_state_property',
-  'match_tool',
-  'damage_source_properties',
-  'location_check',
-  'weather_check',
-  'time_check',
-  'entity_scores',
-  'random_chance',
-  'random_chance_with_looting',
-  'table_bonus',
-  'killed_by_player',
-  'survives_explosion'
-]
-
-const enchantments = [
-  'aqua_affinity',
-  'bane_of_arthropods',
-  'blast_protection',
-  'channeling',
-  'binding_curse',
-  'vanishing_curse',
-  'depth_strider',
-  'efficiency',
-  'feather_falling',
-  'fire_aspect',
-  'fire_protection',
-  'flame',
-  'fortune',
-  'frost_walker',
-  'impaling',
-  'infinity',
-  'knockback',
-  'looting',
-  'loyalty',
-  'luck_of_the_sea',
-  'lure',
-  'mending',
-  'multishot',
-  'piercing',
-  'power',
-  'projectile_protection',
-  'protection',
-  'punch',
-  'quick_charge',
-  'respiration',
-  'riptide',
-  'sharpness',
-  'silk_touch',
-  'smite',
-  'sweeping',
-  'thorns',
-  'unbreaking'
-]
+import { conditions, enchantments } from './Collections'
 
 const entitySources = ['this', 'killer', 'killer_player']
 
-export let PredicateSchema: FilteredNode
-PredicateSchema = new FilteredNode('condition', {
+export const ConditionSchema = new FilteredNode('condition', {
   condition: new EnumNode(conditions, 'random_chance'),
   [Switch]: {
     'alternative': {
-      // terms: new ListNode(PredicateSchema()),
+      terms: new ListNode(
+        new ReferenceNode('condition')
+      ),
     },
     'block_state_property': {
       block: new ResourceNode(),
@@ -100,7 +44,7 @@ PredicateSchema = new FilteredNode('condition', {
       )
     },
     'inverted': {
-      // term: PredicateSchema,
+      term: new ReferenceNode('condition')
     },
     'killed_by_player': {
       inverse: new BooleanNode()
@@ -121,6 +65,11 @@ PredicateSchema = new FilteredNode('condition', {
       chance: new NumberNode({min: 0, max: 1}),
       looting_multiplier: new NumberNode(),
     },
+    'requirements': {
+      terms: new ListNode(
+        new ReferenceNode('condition')
+      ),
+    },
     'reference': {
       name: new StringNode(),
     },
@@ -145,3 +94,5 @@ PredicateSchema = new FilteredNode('condition', {
     chance: 0.5
   })
 })
+
+SchemaRegistry.register('condition', ConditionSchema)
diff --git a/src/schemas/SchemaRegistry.ts b/src/schemas/SchemaRegistry.ts
new file mode 100644
index 00000000..32f7ae2e
--- /dev/null
+++ b/src/schemas/SchemaRegistry.ts
@@ -0,0 +1,17 @@
+import { INode } from "../nodes/AbstractNode";
+
+type Registry = {
+  [id: string]: INode<any>
+}
+
+export class SchemaRegistry {
+  private static registery: Registry = {}
+
+  static register(id: string, node: INode<any>) {
+    SchemaRegistry.registery[id] = node
+  }
+
+  static get(id: string): INode<any> {
+    return SchemaRegistry.registery[id]
+  }
+}