1 files changed, 23 insertions, 0 deletions
diff --git a/lib/error_highlight/formatter.rb b/lib/error_highlight/formatter.rb
new file mode 100644
index 0000000000..20ca78d468
--- /dev/null
+++ b/lib/error_highlight/formatter.rb
@@ -0,0 +1,23 @@
+module ErrorHighlight
+  class DefaultFormatter
+    def self.message_for(spot)
+      # currently only a one-line code snippet is supported
+      if spot[:first_lineno] == spot[:last_lineno]
+        indent = spot[:snippet][0...spot[:first_column]].gsub(/[^\t]/, " ")
+        marker = indent + "^" * (spot[:last_column] - spot[:first_column])
+
+        "\n\n#{ spot[:snippet] }#{ marker }"
+      else
+        ""
+      end
+    end
+  end
+
+  def self.formatter
+    Ractor.current[:__error_highlight_formatter__] || DefaultFormatter
+  end
+
+  def self.formatter=(formatter)
+    Ractor.current[:__error_highlight_formatter__] = formatter
+  end
+end