feat(docs): Documenting noir codegen

docs/docs/getting_started/tooling/noir_codegen.md

@@ -0,0 +1,135 @@
+---
+title: Noir Codegen for Typescript
+description: Learn how to use Noir codegen to generate Typescript bindings 
+keywords: [Nargo, Noir, compile, TypeScript]
+sidebar_position: 2
+---
+
+You can generate TypeScript bindings with `noir_codegen`, allowing for easier and faster integration of your Noir circuits into TypeScript projects.
+
+It is used in conjunction with `nargo export` which generates JSON for specified functions in a Noir library (not binary or contract circuits).
+
+## Installation
+
+You can install `noir_codegen` into your project using `yarn` or `npm`:
+
+```bash
+yarn add @noir-lang/noir_codegen
+```
+
+or 
+
+```bash
+npm install @noir-lang/noir_codegen
+```
+## Usage
+
+### Export ABI of specified functions
+
+Use the `#[export]` macro to indicate which functions in the noir library that you'd like to export.
+```rust
+#[export]
+fn your_function(...
+```
+
+The following command, when run from the directory with `Nargo.toml`, will create a folder with a .json file per exported function:
+
+```bash
+nargo export
+```
+The .json files live in a new `exports` directory.
+
+You can also specify the directory of Noir programs using `--program-dir` as follows:
+
+```bash
+nargo export --program-dir=./path/to/your/noir/program
+```
+
+### Run noir-codegen 
+
+The `noir-codegen` command, pass the path of your exported JSON file(s) (wildcard characters accepted too, `*.json`). :
+
+```bash
+yarn noir-codegen ./export/your_function.json
+```
+
+An `exports` directory is created with an index.ts file containing all exported functions.
+
+You can optionally specify an output dir for your Typescript bindings to live with `--out-dir`:
+
+```bash
+yarn noir-codegen ./export/*.json --out-dir ./path/to/output/dir
+```
+
+
+## Example
+
+For example, if you have a Noir program like this:
+
+```rust
+struct MyStruct {
+    foo: bool,
+    bar: [str<5>; 3],
+    baz: Field
+}
+
+struct NestedStruct {
+    foo: MyStruct,
+    bar: [MyStruct; 3],
+    baz: u64
+}
+#[export]
+fn exported_function_foo(x: u64, y: u64, array: [u8; 5], my_struct: NestedStruct, string: str<5>) -> (u64, u64, MyStruct) {
+    assert(array.len() == 5);
+    assert(my_struct.foo.foo);
+    assert(string == "12345");
+
+    print(x);
+    assert(x < y);
+    (x + y, 3, my_struct.foo)
+}
+
+fn unexported_function(x: u64, y: u64) {
+    assert(x != y);
+}
+```
+
+After following the usage instructions, you will have an `index.ts` that looks like this:
+
+```typescript
+/* Autogenerated file, do not edit! */
+
+/* eslint-disable */
+
+import { Noir, InputMap, CompiledCircuit, ForeignCallHandler } from "@noir-lang/noir_js"
+
+export { ForeignCallHandler } from "@noir-lang/noir_js"
+
+export type u64 = string;
+export type u8 = string | number;
+export type Field = string;
+
+export type MyStruct = {
+  foo: boolean;
+  bar: string[];
+  baz: Field;
+};
+
+export type NestedStruct = {
+  foo: MyStruct;
+  bar: MyStruct[];
+  baz: u64;
+};
+
+
+export const exported_function_foo_circuit: CompiledCircuit = {"abi":{"parameters":[{"name":"x","type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"private"},{"name":"y","type":{"kind":"integer","sign":"unsigned","width":64},"visibility":"private"},{"name":"array","type":{"kind":"array","length":5,"type":{"kind":"integer","sign":"unsigned","width":8}},"visibility":"private"},{"name":"my_struct","type":{"kind":"struct","path":"NestedStruct","fields":[{"name":"foo","type":{"kind":"struct","path":"MyStruct","fields":[{"name":"foo","type":{"kind":"boolean"}},{"name":"bar","type":{"kind":"array","length":3,"type":{"kind":"string","length":5}}},{"name":"baz","type":{"kind":"field"}}]}},{"name":"bar","type":{"kind":"array","length":3,"type":{"kind":"struct","path":"MyStruct","fields":[{"name":"foo","type":{"kind":"boolean"}},{"name":"bar","type":{"kind":"array","length":3,"type":{"kind":"string","length":5}}},{"name":"baz","type":{"kind":"field"}}]}}},{"name":"baz","type":{"kind":"integer","sign":"unsigned","width":64}}]},"visibility":"private"},{"name":"string","type":{"kind":"string","length":5},"visibility":"private"}],"param_witnesses":{"array":[{"start":2,"end":7}],"my_struct":[{"start":7,"end":76}],"string":[{"start":76,"end":81}],"x":[{"start":0,"end":1}],"y":[{"start":1,"end":2}]},"return_type":{"abi_type":{"kind":"tuple","fields":[{"kind":"integer","sign":"unsigned","width":64},{"kind":"integer","sign":"unsigned","width":64},{"kind":"struct","path":"MyStruct","fields":[{"name":"foo","type":{"kind":"boolean"}},{"name":"bar","type":{"kind":"array","length":3,"type":{"kind":"string","length":5}}},{"name":"baz","type":{"kind":"field"}}]}]},"visibility":"private"},"return_witnesses":[83,84,85,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]},"bytecode":"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"};
+
+export async function exported_function_foo(x: u64, y: u64, array: u8[], my_struct: NestedStruct, string: string, foreignCallHandler?: ForeignCallHandler): Promise<[u64, u64, MyStruct]> {
+  const program = new Noir(exported_function_foo_circuit);
+  const args: InputMap = { x, y, array, my_struct, string };
+  const { returnValue } = await program.execute(args, foreignCallHandler);
+  return returnValue as [u64, u64, MyStruct];
+}
+```
+
+As you can see, `exported_function_foo()` is now readily available to us in Typescript, and `unexported_function()` is not.