Gherkin annotated strings (#2252)

* Support annotated strings in Gherkin lexer

* move the visual spec into the visual spec file and out of the demo

* style and don't re-scan triple quotes

* delete a too-brittle spec in favour of the visual spec

---------

Co-authored-by: Luke Redmore <[email protected]>
Co-authored-by: jneen <[email protected]>

Author: 3 people

lib/rouge/lexers/gherkin.rb

@@ -28,10 +28,29 @@ def self.detect?(text)
         rule %r/[ \r\t]+/, Text
       end
 
+      state :annotated_string do
+        rule %r((""")(\S*)(.*?)("""))m do |m|
+          open, lang, content, close = m.captures
+
+          token Str, open
+          token Str::Escape, lang
+
+          sublexer = Rouge::Lexer.find(lang.strip)
+
+          if sublexer
+            delegate sublexer, content
+          else
+            token Str, content
+          end
+
+          token Str, close
+        end
+      end
+
       state :root do
         mixin :basic
         rule %r(\n), Text
-        rule %r(""".*?""")m, Str
+        mixin :annotated_string
         rule %r(@[^\s@]+), Name::Tag
         mixin :has_table
         mixin :has_examples

spec/visual/samples/gherkin

@@ -79,3 +79,52 @@ Feature: Highlander
       Then he (or she) will live forever ;-)
 
   Rule: There can be Two (in some cases)
+
+  Scenario: Code samples
+    Given I have some code examples
+    """ruby
+    class Calculator
+      def multiply(x, y)
+        x * y
+      end
+    end
+    """
+    And I have some code examples
+    """rust
+    fn safe_divide(x: f64, y: f64) -> Result<f64, &'static str> {
+        match y {
+            0.0 => Err("Division by zero"),
+            _ => Ok(x / y),
+        }
+    }
+    """
+    And I have some code examples
+    """ocaml
+    let rec factorial = function
+      | 0 -> 1
+      | n -> n * factorial (n - 1)
+
+    let () = Printf.printf "%d\n" (factorial 5)
+    """
+    And I have some code examples
+    """json
+    {
+      "calculator": {
+        "operations": ["add", "subtract", "multiply", "divide"],
+        "precision": 2,
+        "enabled": true
+      }
+    }
+    """
+    And I have some code examples
+    """nonexistent-lang
+    proc divide(x, y) {
+      return x / y;
+    }
+    """
+    And I have some code examples
+    """
+    def add(a, b)
+      a + b
+    end
+    """