Implemented simple syntax highlighting and symbol-completion.

kalk_cli/Cargo.lock

@@ -1,5 +1,14 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "aho-corasick"
+version = "0.7.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8716408b8bc624ed7f65d223ddb9ac2d044c0547b6fa4b0d554f3a9540496ada"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "ansi_term"
 version = "0.12.1"
@@ -86,22 +95,21 @@ dependencies = [
 ]
 
 [[package]]
-name = "dirs"
-version = "2.0.2"
+name = "dirs-next"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13aea89a5c93364a98e9b37b2fa237effbb694d5cfe01c5b70941f7eb087d5e3"
+checksum = "1cbcf9241d9e8d106295bd496bbe2e9cffd5fa098f2a8c9e2bbcbf09773c11a8"
 dependencies = [
  "cfg-if",
- "dirs-sys",
+ "dirs-sys-next",
 ]
 
 [[package]]
-name = "dirs-sys"
-version = "0.3.4"
+name = "dirs-sys-next"
+version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "afa0b23de8fd801745c471deffa6e12d248f962c9fd4b4c33787b055599bde7b"
+checksum = "9c60f7b8a8953926148223260454befb50c751d3c50e1c178c4fd1ace4083c9a"
 dependencies = [
- "cfg-if",
  "libc",
  "redox_users",
  "winapi",
@@ -143,6 +151,8 @@ version = "0.1.0"
 dependencies = [
  "ansi_term",
  "kalk",
+ "phf",
+ "regex",
  "rustyline",
 ]
 
@@ -328,6 +338,24 @@ dependencies = [
  "rust-argon2",
 ]
 
+[[package]]
+name = "regex"
+version = "1.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c3780fcf44b193bc4d09f36d2a3c87b251da4a046c87795a0d35f4f927ad8e6"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+ "thread_local",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.6.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "26412eb97c6b088a6997e05f69403a802a92d520de2f8e63c2b65f9e0f47c4e8"
+
 [[package]]
 name = "rug"
 version = "1.9.0"
@@ -353,12 +381,12 @@ dependencies = [
 
 [[package]]
 name = "rustyline"
-version = "6.1.2"
+version = "6.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cd20b28d972040c627e209eb29f19c24a71a19d661cc5a220089176e20ee202"
+checksum = "3358c21cbbc1a751892528db4e1de4b7a2b6a73f001e215aaba97d712cfa9777"
 dependencies = [
  "cfg-if",
- "dirs",
+ "dirs-next",
  "libc",
  "log",
  "memchr",
@@ -405,6 +433,15 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "unicode-segmentation"
 version = "1.6.0"

kalk_cli/Cargo.toml

@@ -11,3 +11,5 @@ panic = "abort"
 kalk = { path = "../kalk" }
 rustyline = "6.1.2"
 ansi_term = "0.12"
+regex = "1"
+phf = { version = "0.8", features = ["macros"] }

kalk_cli/src/repl.rs

@@ -1,12 +1,29 @@
 use crate::output;
-use ansi_term::Colour::Cyan;
+use ansi_term::Colour::{self, Cyan};
 use kalk::parser;
+use regex::Captures;
+use regex::Regex;
+use rustyline::completion::Completer;
 use rustyline::error::ReadlineError;
-use rustyline::Editor;
+use rustyline::highlight::Highlighter;
+use rustyline::hint::Hinter;
+use rustyline::hint::HistoryHinter;
+use rustyline::validate::MatchingBracketValidator;
+use rustyline::validate::ValidationContext;
+use rustyline::validate::ValidationResult;
+use rustyline::validate::Validator;
+use rustyline::{Editor, Helper};
+use std::borrow::Cow;
+use std::borrow::Cow::Owned;
 use std::process;
 
 pub fn start(mut parser: &mut parser::Context) {
-    let mut editor = Editor::<()>::new();
+    let mut editor = Editor::<RLHelper>::new();
+    editor.set_helper(Some(RLHelper {
+        highlighter: LineHighlighter {},
+        hinter: HistoryHinter {},
+        validator: MatchingBracketValidator::new(),
+    }));
 
     loop {
         let readline = editor.readline(&Cyan.paint(">> ").to_string());
@@ -30,3 +47,106 @@ fn eval_repl(parser: &mut parser::Context, input: &str) {
         _ => output::eval(parser, input),
     }
 }
+
+struct LineHighlighter {}
+
+impl Highlighter for LineHighlighter {
+    fn highlight<'l>(&self, line: &'l str, _: usize) -> Cow<'l, str> {
+        let mut coloured = line.to_string();
+
+        let reg = Regex::new(r"([A-z]+|[\+-/\*\^!])").unwrap();
+        let unit = Regex::new(r"(deg|rad)").unwrap();
+        let identifier = Regex::new(r"[^0-9\.,\(\)=\+-/\*\^!]+").unwrap();
+        let op = Regex::new(r"[\+-/\*\^!]+").unwrap();
+
+        coloured = reg
+            .replace_all(&coloured, |caps: &Captures| {
+                let cap = &caps[0];
+
+                if unit.is_match(cap) {
+                    Colour::Yellow.paint(cap).to_string()
+                } else if identifier.is_match(cap) {
+                    Colour::Blue.paint(cap).to_string()
+                } else if op.is_match(cap) {
+                    Colour::Fixed(172).paint(cap).to_string()
+                } else {
+                    cap.to_string()
+                }
+            })
+            .to_string();
+
+        Owned(coloured)
+    }
+}
+
+struct RLHelper {
+    highlighter: LineHighlighter,
+    hinter: HistoryHinter,
+    validator: MatchingBracketValidator,
+}
+
+impl Helper for RLHelper {}
+
+const COMPLETION_FUNCS: phf::Map<&'static str, &'static str> = phf::phf_map! {
+    "sqrt" => "√",
+    "deg" => "°",
+};
+
+impl Completer for RLHelper {
+    type Candidate = String;
+    fn complete(
+        &self,
+        line: &str,
+        pos: usize,
+        _ctx: &rustyline::Context<'_>,
+    ) -> Result<(usize, Vec<Self::Candidate>), ReadlineError> {
+        for key in COMPLETION_FUNCS.keys() {
+            if line[..pos].ends_with(key) {
+                return Ok((
+                    pos - key.len(),
+                    vec![String::from(*COMPLETION_FUNCS.get(key).unwrap())],
+                ));
+            }
+        }
+
+        Ok((0, vec![line.to_string()]))
+    }
+}
+
+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)
+    }
+
+    fn highlight_candidate<'c>(
+        &self,
+        candidate: &'c str,
+        _completion: rustyline::CompletionType,
+    ) -> Cow<'c, str> {
+        self.highlighter.highlight(candidate, 0)
+    }
+
+    fn highlight_char(&self, line: &str, _: usize) -> bool {
+        line.len() > 0
+    }
+}
+
+impl Hinter for RLHelper {
+    fn hint(&self, line: &str, a: usize, b: &rustyline::Context) -> Option<String> {
+        self.hinter.hint(line, a, b)
+    }
+}
+
+impl Validator for RLHelper {
+    fn validate(&self, ctx: &mut ValidationContext) -> Result<ValidationResult, ReadlineError> {
+        self.validator.validate(ctx)
+    }
+
+    fn validate_while_typing(&self) -> bool {
+        self.validator.validate_while_typing()
+    }
+}