From d31247992286bef8e808a8777c2c8b9bdb23a783 Mon Sep 17 00:00:00 2001
From: NerdyPepper <akshayoppiliappan@gmail.com>
Date: Tue, 18 Jun 2019 16:25:01 +0530
Subject: add hinter, completer, matching bracket highlighter

---
 src/main.rs | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 75 insertions(+), 9 deletions(-)

(limited to 'src/main.rs')

diff --git a/src/main.rs b/src/main.rs
index 63e886e..1a05904 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -29,7 +29,67 @@ use rustyline::highlight::{ Highlighter, MatchingBracketHighlighter };
 use clap::{Arg, App};
 use lazy_static::lazy_static;
 
-struct LineHelper (MatchingBracketHighlighter, HistoryHinter);
+
+struct RLHelper {
+    completer: FilenameCompleter,
+    highlighter: MatchingBracketHighlighter,
+    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!("\x1b[90m = {}\x1b[0m", ans)),
+            Err(_) => return Some(format!(""))
+        };
+    }
+}
+
+impl Highlighter for RLHelper {
+    fn highlight_prompt<'p>(&self, prompt: &'p str) -> Cow<'p, str> {
+        Owned(String::from(prompt))
+    }
+
+    fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
+        Owned("\x1b[1m".to_owned() + hint + "\x1b[m")
+    }
+
+    fn highlight<'l>(&self, line: &'l str, pos: usize) -> Cow<'l, str> {
+        self.highlighter.highlight(line, pos)
+    }
+
+    fn highlight_char(&self, line: &str, pos: usize) -> bool {
+        self.highlighter.highlight_char(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 {}
 
 struct Configuration {
     radian_mode: bool,
@@ -60,10 +120,16 @@ fn main() {
             .completion_type(CompletionType::Circular)
             .max_history_size(1000)
             .build();
-        let mut rl = Editor::<()>::with_config(config);
+        let mut rl = Editor::with_config(config);
+        let h = RLHelper {
+            completer: FilenameCompleter::new(),
+            highlighter: MatchingBracketHighlighter::new(),
+            hinter: AnswerHinter {}
+        };
+        rl.set_helper(Some(h));
         if rl.load_history("history.txt").is_err() {
-            println!("No previous history.");
-        }
+            println!("No previous history.")
+        };
 
         loop {
             let readline = rl.readline("> ");
@@ -130,11 +196,11 @@ fn parse_arguments() -> Configuration {
             .unwrap_or("10")
             .parse()
             .unwrap(),
-        base: config.value_of("base")
-            .unwrap_or("10")
-            .parse()
-            .unwrap(),
-        input,
+            base: config.value_of("base")
+                .unwrap_or("10")
+                .parse()
+                .unwrap(),
+                input,
     }
 }
 
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