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use std::borrow::Cow::{self,Owned};
use rustyline::error::ReadlineError;
use rustyline::{ Editor, Context, Helper };
use rustyline::config::{ Builder, ColorMode, EditMode, CompletionType };
use rustyline::hint::Hinter;
use rustyline::completion::{ FilenameCompleter, Completer, Pair };
use rustyline::highlight::Highlighter;
use crate::eval_math_expression;
pub struct RLHelper {
completer: FilenameCompleter,
highlighter: LineHighlighter,
hinter: AnswerHinter,
}
struct AnswerHinter { }
impl Hinter for AnswerHinter {
fn hint(&self, line: &str, _: usize, _: &Context) -> Option<String> {
let input = line.trim();
let input = input.replace(" ", "");
if input.len() == 0 {
return Some("".into())
}
let dry_run = eval_math_expression(&input);
match dry_run {
Ok(ans) => return Some(format!(" = {}", ans)),
Err(_) => return Some(format!(""))
};
}
}
struct LineHighlighter { }
impl Highlighter for LineHighlighter {
fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
Owned(format!("\x1b[90m{}\x1b[0m", hint))
}
fn highlight<'l>(&self, line: &'l str, _: usize) -> Cow<'l, str> {
let op = eval_math_expression(line);
match op {
Ok(_) => Owned(line.into()),
Err(_) => Owned(format!("\x1b[31m{}\x1b[0m", line))
}
}
}
impl Highlighter for RLHelper {
fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
self.highlighter.highlight_hint(hint)
}
fn highlight<'l>(&self, line: &'l str, pos: usize) -> Cow<'l, str> {
self.highlighter.highlight(line, pos)
}
}
impl Completer for RLHelper {
type Candidate = Pair;
fn complete(
&self,
line: &str,
pos: usize,
ctx: &Context<'_>,
) -> Result<(usize, Vec<Pair>), ReadlineError> {
self.completer.complete(line, pos, ctx)
}
}
impl Hinter for RLHelper {
fn hint(&self, line: &str, a: usize, b: &Context) -> Option<String> {
self.hinter.hint(line, a, b)
}
}
impl Helper for RLHelper {}
pub fn create_readline() -> Editor<RLHelper> {
let config_builder = Builder::new();
let config = config_builder.color_mode(ColorMode::Enabled)
.edit_mode(EditMode::Emacs)
.history_ignore_space(true)
.completion_type(CompletionType::Circular)
.max_history_size(1000)
.build();
let mut rl = Editor::with_config(config);
let h = RLHelper {
completer: FilenameCompleter::new(),
highlighter: LineHighlighter {},
hinter: AnswerHinter {}
};
rl.set_helper(Some(h));
return rl;
}
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