Add ERB Support

lib/ruby_lsp/document.rb

@@ -180,6 +180,11 @@ def sorbet_sigil_is_true_or_higher
       end
     end
 
+    sig { returns(T::Boolean) }
+    def typechecker_enabled?
+      DependencyDetector.instance.typechecker_for_uri?(uri) && sorbet_sigil_is_true_or_higher
+    end
+
     class Scanner
       extend T::Sig
 

lib/ruby_lsp/erb_document.rb

@@ -0,0 +1,40 @@
+# typed: strict
+# frozen_string_literal: true
+
+require "strscan"
+
+module RubyLsp
+  class ERBDocument < Document
+    sig { override.returns(Prism::ParseResult) }
+    def parse
+      return @parse_result unless @needs_parsing
+
+      @needs_parsing = false
+
+      @parse_result = Prism.parse(scan(@source))
+    end
+
+    private
+
+    sig { params(source: String).returns(String) }
+    def scan(source)
+      scanner = StringScanner.new(source)
+      output = +""
+
+      until scanner.eos?
+        non_ruby_code = scanner.scan_until(/<%(-|=)?/)
+        break unless non_ruby_code
+
+        output << non_ruby_code.gsub(/[^\n]/, " ")
+
+        ruby_code = scanner.scan_until(/(-)?%>/)
+        break unless ruby_code
+
+        output << ruby_code[...-2]
+        output << "  "
+      end
+
+      output
+    end
+  end
+end