diff --git a/implementations/javascript/packages/core/src/pexpr.ts b/implementations/javascript/packages/core/src/pexpr.ts
index f66e292..7315a46 100644
--- a/implementations/javascript/packages/core/src/pexpr.ts
+++ b/implementations/javascript/packages/core/src/pexpr.ts
@@ -1,18 +1,26 @@
 // Preserves-Expressions. https://preserves.dev/preserves-expressions.html
 
 import { ReaderBase } from './reader';
-import { Atom } from './values';
-import { Position } from './annotated';
+import { Atom, Value } from './values';
+import { Position, annotate } from './annotated';
+import { Record as VRecord } from './record';
+import { GenericEmbedded } from './embedded';
+import { fromJS } from './fromjs';
 
 export type Expr = SimpleExpr | Punct;
 export type SimpleExpr = Atom | Compound | Embedded;
 
 export class Punct {
     constructor(public text: string) {}
+    __as_preserve__(): Value { return VRecord(Symbol.for('p'), [Symbol.for(this.text)]); }
 }
 
 export class Embedded {
     constructor(public expr: SimpleExpr, public annotations?: Annotations) {}
+    __as_preserve__(): Value {
+        const v = fromJS(this.expr);
+        return new GenericEmbedded(this.annotations?.wrap(v) ?? v);
+    }
 }
 
 export class BaseCompound<I> {
@@ -33,36 +41,65 @@ export class BaseCompound<I> {
         }
         return this.annotations[index];
     }
+
+    preservesValues(): Value[] {
+        return this.exprs.map((p, i) => {
+            const v = fromJS(p);
+            if (this.annotations?.[i] !== void 0) {
+                return this.annotations[i].wrap(v);
+            } else {
+                return v;
+            }
+        });
+    }
 }
 
-export class Document extends BaseCompound<Expr> {}
+export class Document extends BaseCompound<Expr> {
+    __as_preserve__(): Value {
+        return this.preservesValues();
+    }
+}
 
-export class Annotations extends BaseCompound<SimpleExpr> {}
+export class Annotations extends BaseCompound<SimpleExpr> {
+    wrap(v: Value): Value {
+        return annotate(v, ... this.preservesValues());
+    }
+}
 
 export type CompoundVariant = 'sequence' | 'record' | 'block' | 'group' | 'set';
 
 export abstract class Compound extends BaseCompound<Expr> {
     abstract get variant(): CompoundVariant;
+    __as_preserve__(): Value {
+        const vs = this.preservesValues();
+        switch (this.variant) {
+            case 'sequence': return vs;
+            case 'record': return VRecord(Symbol.for('r'), vs);
+            case 'block': return VRecord(Symbol.for('b'), vs);
+            case 'group': return VRecord(Symbol.for('g'), vs);
+            case 'set': return VRecord(Symbol.for('s'), vs);
+        }
+    }
 }
 
 export class Sequence extends Compound {
-    readonly variant = 'sequence';
+    get variant(): CompoundVariant { return 'sequence'; }
 }
 
 export class Record extends Compound {
-    readonly variant = 'record';
+    get variant(): CompoundVariant { return 'record'; }
 }
 
 export class Block extends Compound {
-    readonly variant = 'block';
+    get variant(): CompoundVariant { return 'block'; }
 }
 
 export class Group extends Compound {
-    readonly variant = 'group';
+    get variant(): CompoundVariant { return 'group'; }
 }
 
 export class Set extends Compound {
-    readonly variant = 'set';
+    get variant(): CompoundVariant { return 'set'; }
 }
 
 export class Reader extends ReaderBase<never> {
diff --git a/implementations/javascript/packages/core/test/pexpr.test.ts b/implementations/javascript/packages/core/test/pexpr.test.ts
index f93ed6a..7a19d5a 100644
--- a/implementations/javascript/packages/core/test/pexpr.test.ts
+++ b/implementations/javascript/packages/core/test/pexpr.test.ts
@@ -1,4 +1,4 @@
-import { Pexpr } from '../src/index';
+import { Pexpr, stringify } from '../src/index';
 import './test-utils';
 
 describe('basics', () => {
@@ -6,5 +6,6 @@ describe('basics', () => {
         const r = new Pexpr.Reader('#!foo\n<bar {zot ::quux}, [a; b; c;]>');
         const d = r.nextDocument();
         console.dir(d, { depth: null });
+        console.log(stringify(d, { indent: 4 }));
     });
 });