Merge pull request #3508 from Earlopain/parser-current-ruby

Author: kddnewton

docs/parser_translation.md

@@ -6,17 +6,23 @@ Prism ships with the ability to translate its syntax tree into the syntax tree u
 
 The `parser` gem provides multiple parsers to support different versions of the Ruby grammar. This includes all of the Ruby versions going back to 1.8, as well as third-party parsers like MacRuby and RubyMotion. The `prism` gem provides another parser that uses the `prism` parser to build the syntax tree.
 
-You can use the `prism` parser like you would any other. After requiring the parser, you should be able to call any of the regular `Parser::Base` APIs that you would normally use.
+You can use the `prism` parser like you would any other. After requiring `prism`, you should be able to call any of the regular `Parser::Base` APIs that you would normally use.
 
 ```ruby
 require "prism"
 
-Prism::Translation::Parser.parse_file("path/to/file.rb")
+# Same as `Parser::Ruby34`
+Prism::Translation::Parser34.parse_file("path/to/file.rb")
+
+# Same as `Parser::CurrentRuby`
+Prism::Translation::ParserCurrent.parse("puts 'Hello World!'")
 ```
 
+All the parsers are autoloaded, so you don't have to worry about requiring them yourself.
+
 ### RuboCop
 
-Prism as a parser engine is directly supported since RuboCop 1.62. The class used for parsing is `Prism::Translation::Parser`.
+Prism as a parser engine is directly supported since RuboCop 1.62.
 
 First, specify `prism` in your Gemfile:
 

lib/prism/translation.rb

@@ -5,6 +5,7 @@ module Prism
   # syntax trees.
   module Translation # steep:ignore
     autoload :Parser, "prism/translation/parser"
+    autoload :ParserCurrent, "prism/translation/parser_current"
     autoload :Parser33, "prism/translation/parser33"
     autoload :Parser34, "prism/translation/parser34"
     autoload :Parser35, "prism/translation/parser35"

lib/prism/translation/parser_current.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+# typed: ignore
+
+module Prism
+  module Translation
+    case RUBY_VERSION
+    when /^3\.3\./
+      ParserCurrent = Parser33
+    when /^3\.4\./
+      ParserCurrent = Parser34
+    when /^3\.5\./
+      ParserCurrent = Parser35
+    else
+      # Keep this in sync with released Ruby.
+      parser = Parser34
+      warn "warning: `Prism::Translation::Current` is loading #{parser.name}, " \
+           "but you are running #{RUBY_VERSION.to_f}."
+      ParserCurrent = parser
+    end
+  end
+end

prism.gemspec

@@ -96,6 +96,7 @@ Gem::Specification.new do |spec|
     "lib/prism/string_query.rb",
     "lib/prism/translation.rb",
     "lib/prism/translation/parser.rb",
+    "lib/prism/translation/parser_current.rb",
     "lib/prism/translation/parser33.rb",
     "lib/prism/translation/parser34.rb",
     "lib/prism/translation/parser35.rb",

test/prism/ruby/parser_test.rb

@@ -155,6 +155,15 @@ def test_non_prism_builder_class_deprecated
       assert_empty(warnings)
     end
 
+    if RUBY_VERSION >= "3.3"
+      def test_current_parser_for_current_ruby
+        major, minor, _patch = Gem::Version.new(RUBY_VERSION).segments
+        # Let's just hope there never is a Ruby 3.10 or similar
+        expected = major * 10 + minor
+        assert_equal(expected, Translation::ParserCurrent.new.version)
+      end
+    end
+
     def test_it_block_parameter_syntax
       it_fixture_path = Pathname(__dir__).join("../../../test/prism/fixtures/it.txt")