syntax highlight rendering, highlighting demo

editor/editor-ideas.md

@@ -60,6 +60,7 @@ These are potentially inspirational resources for the editor's design.
 * Automatically create all "arms" when pattern matching after entering `when var is` based on the type.
     - All `when ... is` should be updated if the type is changed, e.g. adding Indigo to the Color type should add an arm everywhere where `when color is` is used. 
 * When a function is called like `foo(false)`, the name of the boolean argument should be shown automatically; `foo(`*is_active:*`false)`. This should be done for booleans and numbers.
+* Suggest automatically creating a function if the compiler says it does not exist.
 
 
 ### Non-Code Related Inspiration

editor/src/graphics/colors.rs

@@ -1,11 +1,14 @@
-pub const WHITE: (f32, f32, f32, f32) = (1.0, 1.0, 1.0, 1.0);
-pub const TXT_COLOR: (f32, f32, f32, f32) = (1.0, 1.0, 1.0, 1.0);
-pub const CODE_COLOR: (f32, f32, f32, f32) = (0.21, 0.55, 0.83, 1.0);
-pub const CARET_COLOR: (f32, f32, f32, f32) = WHITE;
-pub const SELECT_COLOR: (f32, f32, f32, f32) = (0.45, 0.61, 1.0, 1.0);
-pub const BG_COLOR: (f32, f32, f32, f32) = (0.11, 0.11, 0.13, 1.0);
 
-pub fn to_wgpu_color((r, g, b, a): (f32, f32, f32, f32)) -> wgpu::Color {
+pub type ColorTup = (f32, f32, f32, f32);
+pub const WHITE: ColorTup = (1.0, 1.0, 1.0, 1.0);
+pub const BLACK: ColorTup = (0.0, 0.0, 0.0, 1.0);
+pub const TXT_COLOR: ColorTup = (1.0, 1.0, 1.0, 1.0);
+pub const CODE_COLOR: ColorTup = (0.21, 0.55, 0.83, 1.0);
+pub const CARET_COLOR: ColorTup = WHITE;
+pub const SELECT_COLOR: ColorTup = (0.45, 0.61, 1.0, 1.0);
+pub const BG_COLOR: ColorTup = (0.11, 0.11, 0.13, 1.0);
+
+pub fn to_wgpu_color((r, g, b, a): ColorTup) -> wgpu::Color {
     wgpu::Color {
         r: r as f64,
         g: g as f64,
@@ -14,6 +17,6 @@ pub fn to_wgpu_color((r, g, b, a): (f32, f32, f32, f32)) -> wgpu::Color {
     }
 }
 
-pub fn to_slice((r, g, b, a): (f32, f32, f32, f32)) -> [f32; 4] {
+pub fn to_slice((r, g, b, a): ColorTup) -> [f32; 4] {
     [r, g, b, a]
 }

editor/src/graphics/mod.rs

@@ -2,3 +2,4 @@ pub mod colors;
 pub mod lowlevel;
 pub mod primitives;
 pub mod style;
+mod syntax_highlight;

editor/src/graphics/primitives/text.rs

@@ -2,12 +2,15 @@
 // by Benjamin Hansen, licensed under the MIT license
 
 use super::rect::Rect;
-use crate::graphics::colors::{CODE_COLOR, WHITE};
+use crate::graphics::colors;
+use colors::{CODE_COLOR, WHITE, ColorTup};
 use crate::graphics::style::{CODE_FONT_SIZE, CODE_TXT_XY};
+use crate::graphics::syntax_highlight;
 use ab_glyph::{FontArc, Glyph, InvalidFont};
 use cgmath::{Vector2, Vector4};
 use wgpu_glyph::{ab_glyph, GlyphBrush, GlyphBrushBuilder, GlyphCruncher, Section};
 
+
 #[derive(Debug)]
 pub struct Text {
     pub position: Vector2<f32>,
@@ -82,7 +85,28 @@ fn section_from_text(
     )
 }
 
-// returns glyphs per line
+fn section_from_glyph_text(
+    text: Vec<wgpu_glyph::Text>,
+    screen_position: (f32, f32),
+    area_bounds: (f32, f32),
+    layout: wgpu_glyph::Layout<wgpu_glyph::BuiltInLineBreaker>,
+) -> wgpu_glyph::Section {
+    Section {
+        screen_position,
+        bounds: area_bounds,
+        layout,
+        text
+    }
+}
+
+fn colored_text_to_glyph_text<'a>(text_tups: &'a [(String, ColorTup)]) -> Vec<wgpu_glyph::Text<'a>> {
+    text_tups.iter().map(|(word_string, color_tup)| {
+        wgpu_glyph::Text::new(&word_string)
+            .with_color(colors::to_slice(*color_tup))
+            .with_scale(CODE_FONT_SIZE)
+    }).collect()
+}
+
 pub fn queue_text_draw(text: &Text, glyph_brush: &mut GlyphBrush<()>) {
     let layout = layout_from_text(text);
 
@@ -91,6 +115,23 @@ pub fn queue_text_draw(text: &Text, glyph_brush: &mut GlyphBrush<()>) {
     glyph_brush.queue(section.clone());
 }
 
+pub fn queue_code_text_draw(text: &Text, glyph_brush: &mut GlyphBrush<()>) {
+    let layout = layout_from_text(text);
+
+    let mut all_text_tups: Vec<(String, ColorTup)> = Vec::new();
+    syntax_highlight::highlight_code(text, &mut all_text_tups);
+    let glyph_text_vec = colored_text_to_glyph_text(&all_text_tups);
+
+    let section = section_from_glyph_text(
+        glyph_text_vec,
+        text.position.into(),
+        text.area_bounds.into(),
+        layout
+    );
+
+    glyph_brush.queue(section.clone());
+}
+
 fn glyph_to_rect(glyph: &wgpu_glyph::SectionGlyph) -> Rect {
     let position = glyph.glyph.position;
     let px_scale = glyph.glyph.scale;

editor/src/graphics/style.rs

@@ -1,2 +1,2 @@
 pub const CODE_FONT_SIZE: f32 = 30.0;
-pub const CODE_TXT_XY: (f32, f32) = (30.0, 90.0);
+pub const CODE_TXT_XY: (f32, f32) = (30.0, 30.0);

editor/src/graphics/syntax_highlight.rs

@@ -0,0 +1,74 @@
+
+use crate::graphics::primitives;
+use crate::graphics::colors;
+use colors::ColorTup;
+
+
+//TODO optimize memory allocation
+//TODO this is a demo function, the AST should be used for highlighting, see #904.
+pub fn highlight_code(code_text: &primitives::text::Text, all_text_tups: &mut Vec<(String, ColorTup)>) {
+    let split_code = split_inclusive(&code_text.text);
+
+    let mut active_color = colors::WHITE;
+    let mut same_type_str = String::new();
+
+    for token_seq in split_code {
+        let new_word_color = if token_seq.contains(&'\"'.to_string()) {
+            colors::CODE_COLOR
+        } else if token_seq.contains(&'='.to_string()) {
+            colors::BLACK
+        } else {
+            colors::WHITE
+        };
+
+        if new_word_color != active_color {
+            all_text_tups.push(
+                (
+                    same_type_str,
+                    active_color
+                )
+            );
+
+            active_color = new_word_color;
+            same_type_str = String::new();
+        }
+
+        same_type_str.push_str(&token_seq);
+    }
+
+    if !same_type_str.is_empty() {
+        all_text_tups.push(
+            (
+                same_type_str,
+                active_color
+            )
+        );
+    }
+}
+
+//TODO use rust's split_inclusive once rust 1.50 is released
+fn split_inclusive(code_str: &str) -> Vec<String> {
+    let mut split_vec: Vec<String> = Vec::new();
+    let mut temp_str = String::new();
+    let mut non_space_encountered = false;
+
+    for token in code_str.chars() {
+        if token != ' ' && token != '\n' {
+            non_space_encountered = true;
+            temp_str.push(token);
+        } else if non_space_encountered {
+            split_vec.push(temp_str);
+            temp_str = String::new();
+            temp_str.push(token);
+            non_space_encountered = false;
+        } else {
+            temp_str.push(token);
+        }
+    }
+
+    if !temp_str.is_empty() {
+        split_vec.push(temp_str);
+    }
+
+    split_vec
+}

editor/src/lib.rs

@@ -19,7 +19,7 @@ use crate::graphics::lowlevel::buffer::create_rect_buffers;
 use crate::graphics::lowlevel::ortho::update_ortho_buffer;
 use crate::graphics::lowlevel::pipelines;
 use crate::graphics::primitives::text::{
-    build_glyph_brush, example_code_glyph_rect, queue_text_draw, Text,
+    build_glyph_brush, example_code_glyph_rect, queue_text_draw, queue_code_text_draw, Text,
 };
 use crate::graphics::style::CODE_FONT_SIZE;
 use crate::graphics::style::CODE_TXT_XY;
@@ -392,7 +392,7 @@ fn queue_editor_text(
 
     queue_text_draw(&caret_pos_label, glyph_brush);
 
-    queue_text_draw(&code_text, glyph_brush);
+    queue_code_text_draw(&code_text, glyph_brush);
 }
 
 fn queue_no_file_text(