Refactor Bindgen to simpler form

Refactoring the bindgen with the goal of having a simpler IR-like form
that makes recursively generating types and code easier.

The end goal is to remove all the hairy type portions of the XTP Schema
document. e.g.:

* type
* format
* items
* $ref
* additionalProperties

and replace with a recursively defined type `XtpNormalizedSchema` (name
will likely change to XtpType). I've kept things backwards compatible by
only adding this type on the property `xtpType`. We should switch
bindgens to use this object then we can remove the other properties.

I also decided to change a little bit about the whole process. e.g.:

* moved validation to the parser level code
* remove circularReference detection and blocking
* added some more tests

In order to think more clearly about the whole process, I took up a moment to
write up what I think the whole flow for schemas should be in terms of validating and compiling:

First we validate against JSON schema. This should ensure that we can parse the document into typescript types in the next step. It should not allow any extra values or any values outside of the enum ranges. We should be able to do a simple `const doc = rawDoc as V1Schema` in typescript and the doc object should be valid.

Here we parse the json or yaml into a raw javascript object and cast it to the V1 or V0 schema type. This gives us a raw, but typed representation of the schema. Here we should do extra conditional validation steps that can’t be done (or are too complex to be done) in the JSON Schema. e.g. validating content-type / type pairs, etc.

Here we take the raw parsed types and “normalize” them into a simpler form. We will walk the document and replace all occurrences of $ref, items, additionalProperties, type, and format with a single recursive XtpType.

package.json

@@ -15,12 +15,15 @@
   "devDependencies": {
     "@extism/js-pdk": "^1.0.1",
     "@types/jest": "^29.5.12",
+    "@types/js-yaml": "^4.0.9",
+    "@types/node": "^22.8.1",
     "const": "^1.0.0",
     "esbuild": "^0.17.0",
     "esbuild-plugin-d.ts": "^1.2.3",
     "jest": "^29.0.0",
+    "js-yaml": "^4.1.0",
     "ts-jest": "^29.0.0",
-    "typescript": "^5.0.0"
+    "typescript": "^5.6.3"
   },
   "files": [
     "dist"

src/common.ts

@@ -1,6 +1,6 @@
-export class ValidationError extends Error {
-    constructor(public message: string, public path: string) {
-        super(message);
-        Object.setPrototypeOf(this, ValidationError.prototype);
-    }
+export class ValidationError {
+  constructor(public message: string, public path: string) {
+    this.message = message
+    this.path = path
+  }
 }

src/index.ts

@@ -9,7 +9,9 @@ import {
   XtpSchema,
 } from "./normalizer";
 import { CodeSample } from "./parser";
+import { XtpNormalizedType } from "./types";
 export * from "./normalizer";
+export * from "./types";
 export { ValidationError } from "./common";
 
 export function parse(schema: string) {
@@ -104,9 +106,43 @@ function isPrimitive(p: Property | Parameter): boolean {
   return !!p.$ref.enum || !p.$ref.properties;
 }
 
-function isDateTime(p: Property | Parameter | null): boolean {
-  if (!p) return false;
-  return p.type === "string" && p.format === "date-time";
+export type XtpTyped = { xtpType: XtpNormalizedType } | null;
+
+export function isDateTime(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === 'date-time'
+}
+export function isBuffer(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "buffer"
+}
+export function isObject(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "object"
+}
+export function isArray(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "array"
+}
+export function isEnum(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "enum"
+}
+export function isString(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "string"
+}
+export function isInt32(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "int32"
+}
+export function isInt64(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "int64"
+}
+export function isFloat(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "float"
+}
+export function isDouble(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "double"
+}
+export function isBoolean(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "boolean"
+}
+export function isMap(p: XtpTyped): boolean {
+  return p?.xtpType?.kind === "map"
 }
 
 function capitalize(s: string) {
@@ -135,6 +171,11 @@ export const helpers = {
   codeSamples,
   isDateTime,
   isPrimitive,
+  isBuffer,
+  isObject,
+  isEnum,
+  isArray,
+  isString,
   isJsonEncoded,
   isUtf8Encoded,
   capitalize,