add number highlighting

src/document.rs

@@ -16,7 +16,9 @@ impl Document {
         let contents = fs::read_to_string(filename)?;
         let mut rows = Vec::new();
         for value in contents.lines() {
-            rows.push(Row::from(value));
+            let mut row = Row::from(value);
+            row.highlight();
+            rows.push(row);
         }
         Ok(Self {
             rows,
@@ -45,11 +47,13 @@ impl Document {
         if at.y == self.rows.len() {
             let mut row = Row::default();
             row.insert(0, c);
+            row.highlight();
             self.rows.push(row);
         } else {
             #[allow(clippy::indexing_slicing)]
             let row = &mut self.rows[at.y];
             row.insert(at.x, c);
+            row.highlight();
         }
     }
     #[allow(clippy::indexing_slicing)]
@@ -64,9 +68,11 @@ impl Document {
             let next_row = self.rows.remove(at.y + 1);
             let row = &mut self.rows[at.y];
             row.append(&next_row);
+            row.highlight();
         } else {
             let row = &mut self.rows[at.y];
             row.delete(at.x);
+            row.highlight();
         }
     }
     fn insert_newline(&mut self, at: &Position) {
@@ -78,7 +84,10 @@ impl Document {
             return;
         }
         #[allow(clippy::indexing_slicing)]
-        let new_row = self.rows[at.y].split(at.x);
+        let current_row = &mut self.rows[at.y];
+        let mut new_row = current_row.split(at.x);
+        current_row.highlight();
+        new_row.highlight();
         self.rows.insert(at.y + 1, new_row);
     }
     pub fn save(&mut self) -> Result<(), Error> {

src/highlighting.rs

@@ -0,0 +1,16 @@
+use termion::color;
+
+#[derive(PartialEq)]
+pub enum Type {
+    None,
+    Number
+}
+
+impl Type {
+    pub fn to_color(&self) -> impl color::Color {
+        match self {
+            Type::Number => color::Rgb(220, 163, 163),
+            _ => color::Rgb(255, 255, 255)
+        }
+    }
+}

src/main.rs

@@ -11,6 +11,7 @@ mod document;
 mod editor;
 mod row;
 mod terminal;
+mod highlighting;
 pub use document::Document;
 pub use row::Row;
 pub use editor::SearchDirection;

src/row.rs

@@ -1,18 +1,22 @@
+use crate::highlighting;
 use crate::SearchDirection;
 use std::{cmp, usize};
+use termion::color;
 use unicode_segmentation::UnicodeSegmentation;
 
 #[derive(Default)]
 pub struct Row {
     string: String,
-    len: usize
+    len: usize,
+    highlighting: Vec<highlighting::Type>
 }
 
 impl From<&str> for Row {
     fn from(slice: &str) -> Self {
         Self {
             string: String::from(slice),
-            len: slice.graphemes(true).count()
+            len: slice.graphemes(true).count(),
+            highlighting: Vec::new()
         }
     }
 }
@@ -22,13 +26,27 @@ impl Row {
         let end = cmp::min(end, self.string.len());
         let start = cmp::min(start, end);
         let mut result = String::new();
-        for grapheme in self.string[..].graphemes(true).skip(start).take(end-start) {
-            if grapheme == "\t" {
-                result.push_str("    ");
-            } else {
-                result.push_str(grapheme);
+        let mut current_highlighting = &highlighting::Type::None;
+        for (index, grapheme) in self.string[..].graphemes(true).enumerate().skip(start).take(end-start) {
+            if let Some(c) = grapheme.chars().next() {
+                let highlighting_type = self
+                    .highlighting
+                    .get(index)
+                    .unwrap_or(&highlighting::Type::None);
+                if highlighting_type != current_highlighting {
+                    current_highlighting = highlighting_type;
+                    let start_highlight = format!("{}", termion::color::Fg(highlighting_type.to_color()));
+                    result.push_str(&start_highlight[..]);
+                }
+                if c == '\t' {
+                    result.push_str(" ");
+                } else {
+                    result.push(c);
+                }
             }
         }
+        let end_highlight = format!("{}", termion::color::Fg(color::Reset));
+        result.push_str(&end_highlight[..]);
         result
     }
     pub fn len(&self) -> usize {
@@ -93,7 +111,8 @@ impl Row {
         self.len = length;
         Self {
             string: splitted_row,
-            len: splitted_length
+            len: splitted_length,
+            highlighting: Vec::new()
         }
     }
     pub fn as_bytes(&self) -> &[u8] {
@@ -132,4 +151,15 @@ impl Row {
         }
         None
     }
+    pub fn highlight(&mut self) {
+        let mut highlighting = Vec::new();
+        for c in self.string.chars() {
+            if c.is_ascii_digit() {
+                highlighting.push(highlighting::Type::Number);
+            } else {
+                highlighting.push(highlighting::Type::None);
+            }
+        }
+        self.highlighting = highlighting;
+    }
 }