stwo_vm_runner: add help strings + display help in arg parser (#191)

Author: noam-starkware

crates/vm_runner/src/main.rs

@@ -15,22 +15,22 @@ use stwo_cairo_utils::binary_utils::run_binary;
 use thiserror::Error;
 use tracing::{span, Level};
 
-/// Command line arguments for stwo_vm_runner.
-/// Example command line (use absolute paths):
-///     ```
-///     cargo run -r --bin stwo_vm_runner -- --program path/to/program --program_input
-///     path/to/input --layout <LayoutName> --output_execution_resources_path path/to/output
-///     ```
 #[derive(Parser, Debug)]
 #[clap(author, version, about, long_about = None)]
 struct Args {
-    #[clap(long = "program", help = "Path to the compiled program")]
+    #[clap(long = "program", help = "Absolute path to the compiled program.")]
     program: PathBuf,
-    #[clap(long = "program_input", help = "Path to the program input file.")]
+    #[clap(
+        long = "program_input",
+        help = "Absolute path to the program input file."
+    )]
     program_input: Option<PathBuf>,
-    #[clap(long = "layout")]
+    #[clap(long = "layout", help = "Layout name.")]
     layout: LayoutName,
-    #[structopt(long = "output_execution_resources_path")]
+    #[structopt(
+        long = "output_execution_resources_path",
+        help = "Abosolute path to the program's execution resources (output file)."
+    )]
     output_execution_resources_path: PathBuf,
 }
 
@@ -57,7 +57,10 @@ fn main() -> ExitCode {
 #[allow(clippy::result_large_err)]
 fn run(args: impl Iterator<Item = String>) -> Result<ProverInput, Error> {
     let _span = span!(Level::INFO, "run").entered();
-    let args = Args::try_parse_from(args)?;
+    let args = match Args::try_parse_from(args) {
+        Ok(args) => args,
+        Err(err) => err.exit(),
+    };
 
     let program = get_program(args.program.as_path())?;
     let program_input_contents = get_program_input(&args.program_input)?;