whatever

Author: EnzoPlayer0ne

.envrc

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+if ! has nix_direnv_version || ! nix_direnv_version 3.0.4; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.4/direnvrc" "sha256-DzlYZ33mWF/Gs8DDeyjr8mnVmQGx7ASYqA5WlxwvBG4="
+fi
+
+use flake .
+layout node

.gitignore

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+.direnv/
+.dfx/
+*.wasm*
+*.wat
+*.o

LICENSE.MD

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+# A Zig Canister
+
+Ben Lynn has a blog post series about "Organic Apps", he creates canisters with
+`clang`, and `lld` only.
+
+[Quint](https://github.com/q-uint) and [Enzo](https://github.com/EnzoPlayer0ne), over beers, thought it would be fun to create a canister in zig, so
+we looked at
+Ben's [Hello, Internet Computer](https://fxa77-fiaaa-aaaae-aaana-cai.raw.ic0.app/organic/hello.html)
+blog post and decided to port it to Zig the following day.
+
+Anyways, here is the C code from Ben:
+```c
+#define IMPORT(m,n) __attribute__((import_module(m))) __attribute__((import_name(n)));
+#define EXPORT(n) asm(n) __attribute__((visibility("default")))
+
+void reply_append(void*, unsigned) IMPORT("ic0", "msg_reply_data_append");
+void reply       (void)            IMPORT("ic0", "msg_reply");
+
+void go() EXPORT("canister_query hi");
+
+void go() {
+  char msg[] = "Hello, World!\n";
+  reply_append(msg, sizeof(msg) - 1);
+  reply();
+}
+
+```
+
+And here is our zig code:
+```zig
+extern "ic0" fn msg_reply_data_append(ptr: [*]const u8, len: usize) void;
+extern "ic0" fn msg_reply() void;
+
+comptime {
+    @export(go, .{ .name = "canister_query hi", .linkage = .strong });
+}
+
+fn go() callconv(.C) void {
+    const msg = "Hello, World!\n";
+    msg_reply_data_append(msg, msg.len);
+    msg_reply();
+}
+```
+
+Let's compile the C code:
+```sh
+# we compile the object file
+clang --target=wasm32 -c -O3 src/main.c -o main_c.o
+# we link the object file
+wasm-ld --no-entry --export-dynamic --allow-undefined main_c.o -o main_c.wasm
+# translate to wat
+wasm2wat main_c.wasm > main_c.wat
+# we strip the wasm binary
+wasm-strip main_c.wasm
+```
+
+Let's compile the Zig code:
+```sh
+# we compile zig
+zig build-exe src/main.zig -target wasm32-freestanding -fno-entry -fstrip --export="canister_query hi"
+# translate to wat
+wasm2wat main.wasm > main.wat
+```
+
+Now let's compare the two WASMs:
+```sh
+enzo@merlaux:~/code/zig-cdk$ ll *.wasm
+-rwxrwxr-x 1 enzo enzo 181 May 22 18:03 main.wasm*
+-rwxrwxr-x 1 enzo enzo 308 May 22 18:04 main_c.wasm*
+```
+
+We have created a 181 bytes canister in Zig. Let us see if it works. First we need to create a minimal `dfx.json`:
+```json
+{
+  "canisters": {
+    "hello_zig": {
+      "type": "custom",
+      "build": "",
+      "candid": "not.did",
+      "wasm": "main.wasm"
+    }
+  }
+}
+```
+
+Then let's create a minimal candid file `not.did`:
+```
+service: {}
+```
+
+We check if it actually works, start-up `dfx`:
+```sh
+dfx start
+dfx deploy
+```
+
+Now, let's call the canister:
+```sh
+enzo@merlaux:~/code/zig-cdk$ dfx canister call hello hi --output raw  | xxd -r -p
+WARN: Cannot fetch Candid interface for hi, sending arguments with inferred types.
+Hello, World!
+```
+
+IT WORKS!
+
+## Dev
+
+To replicate the code, install `nix` and `direnv`:
+
+- Install nix with [Determinate Systems Nix Installer](https://github.com/DeterminateSystems/nix-installer)
+
+```sh
+curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install
+```
+
+- Install direnv - [installation page](https://direnv.net/docs/installation.html)
+
+- [hook direnv into your shell](https://direnv.net/docs/hook.html)
+
+Run `direnv allow`. You should be all set-up!

README.md

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+{
+  "canisters": {
+    "hello_zig": {
+      "type": "custom",
+      "build": "",
+      "candid": "not.did",
+      "wasm": "main.wasm"
+    }
+  }
+}

dfx.json

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+{
+  description = "devenv";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+      ...
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+
+        dfxSrc =
+          if system == "x86_64-linux" then
+            {
+              url = "https://github.com/dfinity/sdk/releases/download/0.19.0/dfx-0.19.0-x86_64-linux.tar.gz";
+              sha256 = "c40387d13ab6ed87349fa21a98835f8d384f867333806ee6b9025891ed96e5c5";
+            }
+          else if system == "x86_64-darwin" || system == "aarch64-darwin" then
+            {
+              url = "https://github.com/dfinity/sdk/releases/download/0.19.0/dfx-0.19.0-x86_64-darwin.tar.gz";
+              sha256 = "f61179fa9884f111dbec20c293d77472dcf66d04b0567818fe546437aadd8ce6";
+            }
+          else
+            { };
+
+        dfx = pkgs.stdenv.mkDerivation {
+          name = "dfx-${system}";
+          src = pkgs.fetchurl dfxSrc;
+
+          buildInputs = [
+            pkgs.gnutar
+            pkgs.gzip
+          ];
+
+          unpackPhase = "tar -xzf $src";
+
+          installPhase = ''
+            mkdir -p $out/bin
+            cp dfx $out/bin/
+          '';
+        };
+      in
+      {
+        devShell = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            # ic
+            dfx
+
+            # zig
+            zig
+
+            # wasm
+            wabt
+
+            # to compile C code
+            llvmPackages.bintools
+            llvmPackages.libclang.lib
+            llvmPackages.clang
+
+            # nix
+            nixfmt-rfc-style
+          ];
+
+          shellHook = ''
+            echo "welcome to your nix shell"
+          '';
+        };
+      }
+    );
+}

flake.lock

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+service: {}

flake.nix

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+#define IMPORT(m,n) __attribute__((import_module(m))) __attribute__((import_name(n)));
+#define EXPORT(n) asm(n) __attribute__((visibility("default")))
+
+void reply_append(void*, unsigned) IMPORT("ic0", "msg_reply_data_append");
+void reply       (void)            IMPORT("ic0", "msg_reply");
+
+void go() EXPORT("canister_query hi");
+
+void go() {
+  char msg[] = "Hello, World!\n";
+  reply_append(msg, sizeof(msg) - 1);
+  reply();
+}

not.did

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+extern "ic0" fn msg_reply_data_append(ptr: [*]const u8, len: usize) void;
+extern "ic0" fn msg_reply() void;
+
+comptime {
+    @export(go, .{ .name = "canister_query hi", .linkage = .strong });
+}
+
+fn go() callconv(.C) void {
+    const msg = "Hello, World!\n";
+    msg_reply_data_append(msg, msg.len);
+    msg_reply();
+}