ion-shell 1.0.1

use std::fs::File;
use std::io::Read;
use shell::{Shell, FlowLogic};

/// Evaluates the given file and returns 'SUCCESS' if it succeeds.
pub fn source(shell: &mut Shell, arguments: &[&str]) -> Result<(), String> {
    match arguments.get(1) {
        Some(argument) => {
            if let Ok(mut file) = File::open(&argument) {
                let capacity = file.metadata().map(|x| x.len()).unwrap_or(0) as usize;
                let mut command_list = String::with_capacity(capacity);
                file.read_to_string(&mut command_list)
                    .map_err(|message| format!("ion: {}: failed to read {}\n", message, argument))
                    .map(|_| {
                        for command in command_list.lines() {
                            shell.on_command(command);
                        }
                        ()
                    })
            } else {
                Err(format!("ion: failed to open {}\n", argument))
            }
        },
        None => {
            shell.evaluate_init_file();
            Ok(())
        },
    }
}