Switch to Rouge for syntax highlighting and add dark syntax-highlighting theme

better_errors.gemspec

@@ -31,7 +31,7 @@ Gem::Specification.new do |s|
   # simplecov and coveralls must not be included here. See the Gemfiles instead.
 
   s.add_dependency "erubi", ">= 1.0.0"
-  s.add_dependency "coderay", ">= 1.0.0"
+  s.add_dependency "rouge", ">= 1.0.0"
   s.add_dependency "rack", ">= 0.9.0"
 
   # optional dependencies:

lib/better_errors.rb

@@ -1,6 +1,5 @@
 require "pp"
 require "erubi"
-require "coderay"
 require "uri"
 
 require "better_errors/version"

lib/better_errors/code_formatter.rb

@@ -4,14 +4,6 @@ class CodeFormatter
     require "better_errors/code_formatter/html"
     require "better_errors/code_formatter/text"
 
-    FILE_TYPES = {
-      ".rb"   => :ruby,
-      ""      => :ruby,
-      ".html" => :html,
-      ".erb"  => :erb,
-      ".haml" => :haml
-    }
-
     attr_reader :filename, :line, :context
 
     def initialize(filename, line, context = 5)
@@ -26,13 +18,21 @@ def output
       source_unavailable
     end
 
-    def formatted_code
-      formatted_lines.join
+    def line_range
+      min = [line - context, 1].max
+      max = [line + context, source_lines.count].min
+      min..max
     end
 
-    def coderay_scanner
-      ext = File.extname(filename)
-      FILE_TYPES[ext] || :text
+    def context_lines
+      range = line_range
+      source_lines[(range.begin - 1)..(range.end - 1)] or raise Errno::EINVAL
+    end
+
+    private
+
+    def formatted_code
+      formatted_lines.join
     end
 
     def each_line_of(lines, &blk)
@@ -41,23 +41,12 @@ def each_line_of(lines, &blk)
       }
     end
 
-    def highlighted_lines
-      CodeRay.scan(context_lines.join, coderay_scanner).html(css: :class).lines
-    end
-
-    def context_lines
-      range = line_range
-      source_lines[(range.begin - 1)..(range.end - 1)] or raise Errno::EINVAL
+    def source
+      @source ||= File.read(filename)
     end
 
     def source_lines
-      @source_lines ||= File.readlines(filename)
-    end
-
-    def line_range
-      min = [line - context, 1].max
-      max = [line + context, source_lines.count].min
-      min..max
+      @source_lines ||= source.lines
     end
   end
 end

lib/better_errors/code_formatter/html.rb

@@ -1,3 +1,5 @@
+require "rouge"
+
 module BetterErrors
   # @private
   class CodeFormatter::HTML < CodeFormatter
@@ -8,7 +10,7 @@ def source_unavailable
     def formatted_lines
       each_line_of(highlighted_lines) { |highlight, current_line, str|
         class_name = highlight ? "highlight" : ""
-        sprintf '<pre class="CodeRay %s">%s</pre>', class_name, str
+        sprintf '<pre class="%s">%s</pre>', class_name, str
       }
     end
 
@@ -20,7 +22,19 @@ def formatted_nums
     end
 
     def formatted_code
-      %{<div class="code_linenums">#{formatted_nums.join}</div><div class="code">#{super}</div>}
+      %{
+        <div class="code_linenums">#{formatted_nums.join}</div>
+        <div class="code"><div class='code-wrapper'>#{super}</div></div>
+      }
+    end
+
+    def rouge_lexer
+      Rouge::Lexer.guess(filename: filename, source: source) { Rouge::Lexers::Ruby }
     end
+
+    def highlighted_lines
+      Rouge::Formatters::HTML.new.format(rouge_lexer.lex(context_lines.join)).lines
+    end
+
   end
 end

lib/better_errors/error_page.rb

@@ -1,6 +1,7 @@
 require "cgi"
 require "json"
 require "securerandom"
+require "rouge"
 require "better_errors/error_page_style"
 
 module BetterErrors
@@ -158,7 +159,7 @@ def eval_and_respond(index, code)
       result, prompt, prefilled_input = @repls[index].send_input(code)
 
       {
-        highlighted_input: CodeRay.scan(code, :ruby).div(wrap: nil),
+        highlighted_input: Rouge::Formatters::HTML.new.format(Rouge::Lexers::Ruby.lex(code)),
         prefilled_input:   prefilled_input,
         prompt:            prompt,
         result:            result

lib/better_errors/style/main.scss

@@ -487,12 +487,14 @@ p.no-javascript-notice {
 }
 
 .code, .be-console, .unavailable {
-    background: #fff;
     padding: 5px;
-
     box-shadow: inset 3px 3px 3px rgba(0, 0, 0, 0.1), inset 0 0 0 1px rgba(0, 0, 0, 0.1);
 }
 
+.code, .unavailable {
+    text-shadow: none;
+}
+
 .code_linenums{
     background:#f1f1f1;
     padding-top:10px;
@@ -505,16 +507,35 @@ p.no-javascript-notice {
     padding:0 12px;
 }
 
+.code, .be-console .syntax-highlighted {
+    text-shadow: none;
+
+    @import "syntax_highlighting";
+}
+.code {
+    // For now, the syntax-highlighted console only supports light mode.
+    // Once the entire page has a dark theme, this should change.
+    @media (prefers-color-scheme: dark) {
+        @import "syntax_highlighting_dark";
+    }
+}
+
 .code {
     margin-bottom: -1px;
     border-top-left-radius:2px;
     padding: 10px 0;
     overflow: auto;
-}
 
-.code pre{
-    padding-left:12px;
-    min-height:16px;
+    .code-wrapper {
+      // This fixes the highlight or other background of the pre not stretching the full scrollable width.
+      display: inline-block;
+      min-width: 100%;
+    }
+
+    pre {
+        padding-left:12px;
+        min-height:16px;
+    }
 }
 
 /* Source unavailable */
@@ -537,28 +558,32 @@ p.unavailable:before {
     margin-bottom: -10px;
 }
 
+$code-highlight-background: rgba(51, 136, 170, 0.15);
+$code-highlight-background-flash: adjust-color($code-highlight-background, $alpha: 0.3);
+
 @-webkit-keyframes highlight {
-    0%   { background: rgba(220, 30, 30, 0.3); }
-    100% { background: rgba(220, 30, 30, 0.1); }
+    0%   { background: $code-highlight-background-flash; }
+    100% { background: $code-highlight-background; }
 }
 @-moz-keyframes highlight {
-    0%   { background: rgba(220, 30, 30, 0.3); }
-    100% { background: rgba(220, 30, 30, 0.1); }
+    0%   { background: $code-highlight-background-flash; }
+    100% { background: $code-highlight-background; }
 }
 @keyframes highlight {
-    0%   { background: rgba(220, 30, 30, 0.3); }
-    100% { background: rgba(220, 30, 30, 0.1); }
+    0%   { background: $code-highlight-background-flash; }
+    100% { background: $code-highlight-background; }
 }
 
 .code .highlight, .code_linenums .highlight {
-    background: rgba(220, 30, 30, 0.1);
+    background: $code-highlight-background;
     -webkit-animation: highlight 400ms linear 1;
     -moz-animation: highlight 400ms linear 1;
     animation: highlight 400ms linear 1;
 }
 
 /* REPL shell */
 .be-console {
+    background: #fff;
     padding: 0 1px 10px 1px;
     border-bottom-left-radius: 2px;
     border-bottom-right-radius: 2px;
@@ -719,5 +744,3 @@ nav.sidebar:hover::-webkit-scrollbar-thumb {
 .code:hover::-webkit-scrollbar-thumb {
     background: #888;
 }
-
-@import "syntax_highlighting";