Add dis example

Author: coolreader18

examples/dis.rs

@@ -0,0 +1,91 @@
+/// This an example usage of the rustpython_compiler crate.
+/// This program reads, parses, and compiles a file you provide
+/// to RustPython bytecode, and then displays the output in the
+/// `dis.dis` format.
+///
+/// example usage:
+/// $ cargo run --release --example dis demo.py
+
+#[macro_use]
+extern crate clap;
+extern crate env_logger;
+#[macro_use]
+extern crate log;
+
+use clap::{App, Arg};
+
+use rustpython_compiler::compile;
+use std::error::Error;
+use std::fs;
+use std::path::Path;
+
+fn main() {
+    env_logger::init();
+    let app = App::new("parse_folders")
+        .version(crate_version!())
+        .author(crate_authors!())
+        .about("Walks over all .py files in a folder, and parses them.")
+        .arg(
+            Arg::with_name("scripts")
+                .help("Scripts to scan")
+                .multiple(true)
+                .required(true),
+        )
+        .arg(
+            Arg::with_name("mode")
+                .help("The mode to compile the scripts in")
+                .long("mode")
+                .short("m")
+                .possible_values(&["exec", "single", "eval"])
+                .takes_value(true),
+        )
+        .arg(
+            Arg::with_name("no_expand")
+                .help(
+                    "Don't expand CodeObject LoadConst instructions to show \
+                     the instructions inside",
+                )
+                .long("no-expand")
+                .short("x"),
+        )
+        .arg(
+            Arg::with_name("optimize")
+                .help("The amount of optimization to apply to the compiled bytecode")
+                .short("O")
+                .multiple(true),
+        );
+    let matches = app.get_matches();
+
+    let mode = matches.value_of_lossy("mode").unwrap().parse().unwrap();
+    let expand_codeobjects = !matches.is_present("no_expand");
+    let optimize = matches.occurrences_of("optimize") as u8;
+    let scripts = matches.values_of_os("scripts").unwrap();
+
+    for script in scripts.map(Path::new) {
+        if script.exists() && script.is_file() {
+            let res = display_script(script, mode, optimize, expand_codeobjects);
+            if let Err(e) = res {
+                error!("Error while compiling {:?}: {}", script, e);
+            }
+        } else {
+            eprintln!("{:?} is not a file.", script);
+        }
+    }
+}
+
+fn display_script(
+    path: &Path,
+    mode: compile::Mode,
+    optimize: u8,
+    expand_codeobjects: bool,
+) -> Result<(), Box<dyn Error>> {
+    let source = fs::read_to_string(path)?;
+    let code = compile::compile(&source, mode, path.to_string_lossy().into_owned(), optimize)?;
+    println!("{}:", path.display());
+    if expand_codeobjects {
+        println!("{}", code.display_expand_codeobjects());
+    } else {
+        println!("{}", code);
+    }
+    Ok(())
+}