feat: add eval command (#23)

README.md

@@ -351,33 +351,34 @@ notes.
 # CLI
 
 ```
-  Usage:   dzx [script] [args...]
-  Version: 0.3.0
-
-  Description:
-
-    🦕 A custom deno runtime for fun.
-
-  Options:
-
-    -h, --help       - Show this help.
-    -V, --version    - Show the version number for this program.
-    -A, --allow-all  - Allow all permissions.                                           (Depends: --worker)
-    --allow-env      - Allow environment access.                                        (Depends: --worker)
-    --allow-hrtime   - Allow high resolution time measurement.                          (Depends: --worker)
-    --allow-net      - Allow network access.                                            (Depends: --worker)
-    --allow-ffi      - Allow loading dynamic libraries.                                 (Depends: --worker)
-    --allow-read     - Allow file system read access.                                   (Depends: --worker)
-    --allow-run      - Allow running subprocesses.                                      (Depends: --worker)
-    --allow-write    - Allow file system write access.                                  (Depends: --worker)
-    -w, --worker     - Run script in an isolated web worker with it's own permissions.
-
-  Commands:
-
-    bundle   [script]                                           - Bundle an dzx script to a standalone deno sript.
-    compile  [compile-options...] [script] [script-options...]  - Combile an dzx script to a standalone binary.
-    repl                                                        - Start a dzx repl
-    upgrade                                                     - Upgrade dzx executable to latest or given version.
+Usage:   dzx [script] [args...]
+Version: 0.3.0
+
+Description:
+
+  🦕 A custom deno runtime for fun.
+
+Options:
+
+  -h, --help       - Show this help.
+  -V, --version    - Show the version number for this program.
+  -A, --allow-all  - Allow all permissions.                                           (Depends: --worker)
+  --allow-env      - Allow environment access.                                        (Depends: --worker)
+  --allow-hrtime   - Allow high resolution time measurement.                          (Depends: --worker)
+  --allow-net      - Allow network access.                                            (Depends: --worker)
+  --allow-ffi      - Allow loading dynamic libraries.                                 (Depends: --worker)
+  --allow-read     - Allow file system read access.                                   (Depends: --worker)
+  --allow-run      - Allow running subprocesses.                                      (Depends: --worker)
+  --allow-write    - Allow file system write access.                                  (Depends: --worker)
+  -w, --worker     - Run script in an isolated web worker with it's own permissions.
+
+Commands:
+
+  bundle   [script]                                           - Bundle an dzx script to a standalone deno sript.
+  compile  [compile-options...] [script] [script-options...]  - Combile an dzx script to a standalone binary.
+  eval     <code>                                             - Evaluate a dzx script from the command line.
+  repl                                                        - Start a dzx repl.
+  upgrade                                                     - Upgrade dzx executable to latest or given version.
 ```
 
 - **dzx** `[script] [...args]`: Run a local or remote dzx script (optional in a
@@ -412,9 +413,41 @@ notes.
   > flag with your permissions to specify the output file name, otherwise the
   > compiled file will be emitted with a random value as its name.
 
-- **dzx repl**: Start a dzx repl (deno repl bootstrapped with dzx).
+- **dzx eval**: Evaluate a dzx script from command line.
+
+  ```shell
+  dzx eval "console.log($.shell)"
+  ```
+
+  Eval can also read from stdin:
+
+  ```shell
+  echo "console.log($.shell)" | dzx eval
+  ```
+
+- **dzx repl**: Start a dzx repl (Read eval print loop).
 
-- **dzx upgrade**: Start a dzx repl.
+  The `repl` command starts a deno repl bootstrapped with the dzx runtime code.
+
+- **dzx upgrade**: Upgrade the `dzx` executable to latest or given version.
+
+  Upgrade to latest version:
+
+  ```shell
+  dzx upgrade
+  ```
+
+  Upgrade to specific version:
+
+  ```shell
+  dzx upgrade --version 3.0.0
+  ```
+
+  List all available versions:
+
+  ```shell
+  dzx upgrade --list-versions
+  ```
 
 ## Contributing
 

src/cli/eval.ts

@@ -0,0 +1,33 @@
+import { Command, ValidationError } from "./deps.ts";
+import { bootstrapScript, importModule } from "./lib/bootstrap.ts";
+import { getModuleFromStdin } from "./lib/stream.ts";
+
+export function evalCommand() {
+  return new Command<void>()
+    .description(`Evaluate a dzx script from the command line.\n
+  dzx eval "console.log($.shell)"\n
+Or read from stdin:\n
+  echo "console.log($.shell)" | dzx eval
+`)
+    .arguments("<code:string>")
+    .useRawArgs()
+    .action(
+      async function (_: void, ...args: Array<string>) {
+        if (["-h", "--help"].includes(args[0])) {
+          this.showHelp();
+          Deno.exit(0);
+        }
+        const code = args.shift();
+
+        if (!code && Deno.isatty(Deno.stdin.rid)) {
+          throw new ValidationError(`Missing argument(s): script`);
+        }
+
+        const mainModule: string = code
+          ? bootstrapScript(code)
+          : await getModuleFromStdin();
+
+        await importModule({ mainModule });
+      },
+    );
+}

src/cli/mod.ts

@@ -9,6 +9,7 @@ import {
   ValidationError,
 } from "./deps.ts";
 import { addProtocol } from "../_utils.ts";
+import { evalCommand } from "./eval.ts";
 import { importModule } from "./lib/bootstrap.ts";
 import { getModuleFromStdin } from "./lib/stream.ts";
 import { getMarkdownModule } from "./lib/markdown.ts";
@@ -102,6 +103,7 @@ export function dzx() {
     )
     .command("bundle", bundleCommand())
     .command("compile", compileCommand())
+    .command("eval", evalCommand())
     .command("repl", replCommand())
     .command(
       "upgrade",

src/cli/repl.ts

@@ -3,7 +3,7 @@ import { Command } from "./deps.ts";
 
 export function replCommand() {
   return new Command<void>()
-    .description("Start a dzx repl")
+    .description("Start a dzx repl.")
     .option(
       "--compat",
       "Node compatibility mode. Currently only enables built-in node modules like 'fs' and globals like 'process'",