61 lines
2.1 KiB
Rust
61 lines
2.1 KiB
Rust
use ablescript::interpret::ExecEnv;
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use ablescript::parser::parse;
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use rustyline::Editor;
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pub fn repl(ast_print: bool) {
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let mut rl = Editor::<()>::new();
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let mut env = ExecEnv::<ablescript::host_interface::Standard>::default();
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// If this is `Some`, the user has previously entered an
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// incomplete statement and is now completing it; otherwise, the
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// user is entering a completely new statement.
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let mut partial: Option<String> = None;
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loop {
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match rl.readline(if partial.is_some() { ">> " } else { ":: " }) {
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Ok(readline) => {
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let readline = readline.trim_end();
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rl.add_history_entry(readline);
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let partial_data = match partial {
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Some(line) => line + readline,
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None => readline.to_owned(),
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};
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partial = match parse(&partial_data).and_then(|ast| {
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if ast_print {
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println!("{:#?}", &ast);
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}
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env.eval_stmts(&ast)
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}) {
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Ok(_) => None,
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Err(ablescript::error::Error {
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// Treat "Unexpected EOF" errors as "we need
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// more data".
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kind: ablescript::error::ErrorKind::UnexpectedEoi,
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..
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}) => Some(partial_data),
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Err(e) => {
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println!("{}", e);
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println!(" | {}", partial_data);
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println!(
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" {}{}",
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" ".repeat(e.span.start),
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"^".repeat((e.span.end - e.span.start).max(1))
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);
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None
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}
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};
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}
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Err(rustyline::error::ReadlineError::Eof) => {
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println!("bye");
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break;
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}
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Err(rustyline::error::ReadlineError::Interrupted) => (),
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Err(e) => {
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println!("Error: {:?}", e);
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break;
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}
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}
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}
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}
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