Add interactive shell

Author: windelbouwman

parser/src/lib.rs

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate log;
 
-mod parser;
+pub mod parser;
 mod python;
 pub mod ast;
 mod token;

src/main.rs

@@ -11,7 +11,11 @@ mod compile;
 use clap::{Arg, App};
 use std::path::Path;
 use rustpython_parser::parse;
+use rustpython_parser::parser::parse_source;
 use rustpython_vm::evaluate;
+use rustpython_vm::pyobject::PyObjectRef;
+use std::io;
+use std::io::prelude::*;
 
 
 fn main() {
@@ -21,18 +25,24 @@ fn main() {
       .author(crate_authors!())
       .about("Rust implementation of the Python language")
       .arg(Arg::with_name("script")
-          .required(true)
+          .required(false)
           .index(1))
       .arg(Arg::with_name("v")
           .short("v")
           .multiple(true)
           .help("Give the verbosity"))
       .get_matches();
 
-  // Figure out the filename:
-  let script_file = matches.value_of("script").unwrap_or("foo");
-  debug!("Running file {}", script_file);
+  // Figure out if a script was passed:
+  match matches.value_of("script") {
+      None => run_shell(),
+      Some(filename) => run_script(&filename.to_string()),
+  }
 
+}
+
+fn run_script(script_file: &String) {
+  debug!("Running file {}", script_file);
   // Parse an ast from it:
   let filepath = Path::new(script_file);
   match parse(filepath) {
@@ -49,3 +59,31 @@ fn main() {
   }
 }
 
+fn run_shell() {
+    println!("Welcome to the magnificent Rust Python interpreter");
+    // Read a single line:
+    loop {
+        let mut input = String::new();
+        print!(">>>");
+        io::stdout().flush().ok().expect("Could not flush stdout");
+        io::stdin().read_line(&mut input);
+        println!("You entered {:?}", input);
+        let result = eval(&input);
+        println!("{:?}", result);
+    }
+}
+
+fn eval(source: &String) -> Result<PyObjectRef, PyObjectRef> {
+  match parse_source(source) {
+    Ok(program) => {
+      debug!("Got ast: {:?}", program);
+      let bytecode = compile::compile(program);
+      debug!("Code object: {:?}", bytecode);
+      evaluate(bytecode)
+    },
+    Err(msg) => {
+        panic!("Parsing went horribly wrong: {}", msg);
+    },
+  }
+}
+