schala/schala-repl/src/repl/help.rs

use std::fmt::Write as FmtWrite;

use super::{Repl, InterpreterDirectiveOutput};

pub fn help(repl: &mut Repl, arguments: &[&str]) -> InterpreterDirectiveOutput {
  match arguments {
    [] =>  return global_help(repl),
    commands => {
      let dirs = repl.get_directives();
      let mut directive_list = dirs.get_children();
      let mut matched_directive = None;
      for cmd in commands {
        let found = directive_list.iter().find(|directive| directive.get_cmd() == *cmd);
        if let Some(dir) = found {
            directive_list = dir.get_children();
        }

        matched_directive = found;
      }

      Some(if let Some(dir) = matched_directive {
        format!("{}", dir.get_help())
      } else {
        format!("Last command not found")
      })
    }
  }
}

fn global_help(repl: &mut Repl) -> InterpreterDirectiveOutput {
  let mut buf = String::new();

  writeln!(buf, "MetaInterpreter options").unwrap();
  writeln!(buf, "-----------------------").unwrap();

  for directive in repl.get_directives().get_children() {
    let trailer = " ";
    writeln!(buf, "{}{}- {}", directive.get_cmd(), trailer, directive.get_help()).unwrap();
  }

  let ref lang = repl.get_cur_language_state();
  writeln!(buf, "").unwrap();
  writeln!(buf, "Language-specific help for {}", lang.get_language_name()).unwrap();
  writeln!(buf, "-----------------------").unwrap();
  Some(buf)
}