From 574209966bee9369dcb25d9ab4758aa5397b77bc Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Wed, 26 Jan 2022 16:03:13 +0100
Subject: [PATCH] Better stringification

---
 .../javascript/packages/core/src/embedded.ts  |  1 -
 .../javascript/packages/core/src/encoder.ts   |  4 ---
 .../javascript/packages/core/src/text.ts      | 25 ++++++++++++++--
 .../javascript/packages/core/src/writer.ts    | 29 ++++++++++++-------
 4 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/implementations/javascript/packages/core/src/embedded.ts b/implementations/javascript/packages/core/src/embedded.ts
index 705b36d..1df670f 100644
--- a/implementations/javascript/packages/core/src/embedded.ts
+++ b/implementations/javascript/packages/core/src/embedded.ts
@@ -5,7 +5,6 @@ import { ReaderStateOptions } from "./reader";
 
 export type EmbeddedTypeEncode<T> = {
     encode(s: EncoderState, v: T): void;
-    toValue(v: T): Value<GenericEmbedded>;
 }
 
 export type EmbeddedTypeDecode<T> = {
diff --git a/implementations/javascript/packages/core/src/encoder.ts b/implementations/javascript/packages/core/src/encoder.ts
index a3ce94f..011fa56 100644
--- a/implementations/javascript/packages/core/src/encoder.ts
+++ b/implementations/javascript/packages/core/src/encoder.ts
@@ -48,10 +48,6 @@ export function embeddedId(v: any): number {
 export const identityEmbeddedTypeEncode: EmbeddedTypeEncode<any> = {
     encode(s: EncoderState, v: any): void {
         new Encoder(s, this).push(embeddedId(v));
-    },
-
-    toValue(v: any): Value<GenericEmbedded> {
-        return embeddedId(v);
     }
 };
 
diff --git a/implementations/javascript/packages/core/src/text.ts b/implementations/javascript/packages/core/src/text.ts
index 2117137..158f670 100644
--- a/implementations/javascript/packages/core/src/text.ts
+++ b/implementations/javascript/packages/core/src/text.ts
@@ -1,12 +1,33 @@
-import type { GenericEmbedded } from './embedded';
+import { GenericEmbedded } from './embedded';
 import type { Value } from './values';
 
 import { Annotated } from './annotated';
 import { Bytes } from './bytes';
 import { KeyedDictionary, KeyedSet } from './dictionary';
-import { Writer, Writable, WriterOptions } from './writer';
+import { Writer, Writable, WriterOptions, EmbeddedWriter, WriterState } from './writer';
+import { fromJS } from './fromjs';
+
+export const stringifyEmbeddedWrite: EmbeddedWriter<any> = {
+    write(s: WriterState, v: any): void {
+        if (v instanceof GenericEmbedded) {
+            new Writer(s, this).push(v.generic);
+        } else {
+            try {
+                const o = fromJS(v);
+                new Writer(s, this).push(v);
+                return;
+            } catch {}
+            try {
+                s.pieces.push(JSON.stringify(v));
+            } catch {}
+            s.pieces.push('⌜' + v + '⌝');
+        }
+    }
+};
 
 export function stringify<T = GenericEmbedded>(x: any, options?: WriterOptions<T>): string {
+    options = { ... (options ?? {}) };
+    options.embeddedWrite = options.embeddedWrite ?? stringifyEmbeddedWrite;
     return Writer.stringify(x as Writable<T>, options);
 }
 
diff --git a/implementations/javascript/packages/core/src/writer.ts b/implementations/javascript/packages/core/src/writer.ts
index 7de2eeb..be55d34 100644
--- a/implementations/javascript/packages/core/src/writer.ts
+++ b/implementations/javascript/packages/core/src/writer.ts
@@ -19,7 +19,10 @@ function isIterable<T>(v: any): v is Iterable<T> {
     return typeof v === 'object' && v !== null && typeof v[Symbol.iterator] === 'function';
 }
 
-export const genericEmbeddedTypeEncode: EmbeddedTypeEncode<GenericEmbedded> = {
+export type EmbeddedWriter<T> =
+    { write(s: WriterState, v: T): void } | { toValue(v: T): Value<GenericEmbedded> };
+
+export const genericEmbeddedTypeEncode: EmbeddedTypeEncode<GenericEmbedded> & EmbeddedWriter<GenericEmbedded> = {
     encode(s: EncoderState, v: GenericEmbedded): void {
         new Encoder(s, this).push(v.generic);
     },
@@ -29,13 +32,13 @@ export const genericEmbeddedTypeEncode: EmbeddedTypeEncode<GenericEmbedded> = {
     }
 };
 
-export const neverEmbeddedTypeEncode: EmbeddedTypeEncode<never> = {
+export const neverEmbeddedTypeEncode: EmbeddedTypeEncode<never> & EmbeddedWriter<never> = {
     encode(_s: EncoderState, _v: never): void {
         throw new Error("Embeddeds not permitted encoding Preserves document");
     },
 
     toValue(_v: never): Value<GenericEmbedded> {
-        throw new Error("Embeddeds not permitted encoding Preserves document");
+        throw new Error("Embeddeds not permitted writing Preserves document");
     }
 };
 
@@ -47,7 +50,7 @@ export interface WriterStateOptions {
 }
 
 export interface WriterOptions<T> extends WriterStateOptions {
-    embeddedEncode?: EmbeddedTypeEncode<T>;
+    embeddedWrite?: EmbeddedWriter<T>;
 }
 
 export class WriterState {
@@ -225,20 +228,20 @@ export function encodeBase64(bs: Uint8Array): string {
 
 export class Writer<T> {
     state: WriterState;
-    embeddedType: EmbeddedTypeEncode<T>;
+    embeddedWrite: EmbeddedWriter<T>;
 
-    constructor(state: WriterState, embeddedType: EmbeddedTypeEncode<T>);
+    constructor(state: WriterState, embeddedWrite: EmbeddedWriter<T>);
     constructor(options?: WriterOptions<T>);
     constructor(
         state_or_options: (WriterState | WriterOptions<T>) = {},
-        embeddedType?: EmbeddedTypeEncode<T>
+        embeddedWrite?: EmbeddedWriter<T>
     ) {
         if (state_or_options instanceof WriterState) {
             this.state = state_or_options;
-            this.embeddedType = embeddedType!;
+            this.embeddedWrite = embeddedWrite!;
         } else {
             this.state = new WriterState(state_or_options);
-            this.embeddedType = state_or_options.embeddedEncode ?? neverEmbeddedTypeEncode;
+            this.embeddedWrite = state_or_options.embeddedWrite ?? neverEmbeddedTypeEncode;
         }
     }
 
@@ -315,8 +318,12 @@ export class Writer<T> {
                 else {
                     ((v: Embedded<T>) => {
                         this.state.pieces.push('#!');
-                        new Writer(this.state, genericEmbeddedTypeEncode)
-                            .push(this.embeddedType.toValue(v.embeddedValue));
+                        if ('write' in this.embeddedWrite) {
+                            this.embeddedWrite.write(this.state, v.embeddedValue);
+                        } else {
+                            new Writer(this.state, genericEmbeddedTypeEncode)
+                                .push(this.embeddedWrite.toValue(v.embeddedValue));
+                        }
                     })(v);
                 }
                 break;