[close #16] Replace Parser with Ripper

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## HEAD (unreleased)
 
+## 0.1.4
+
+- Parser gem replaced with Ripper (https://github.com/zombocom/syntax_search/pull/17)
+
 ## 0.1.3
 
 - Internal refactor (https://github.com/zombocom/syntax_search/pull/13)

Gemfile.lock

@@ -1,16 +1,12 @@
 PATH
   remote: .
   specs:
-    syntax_search (0.1.3)
-      parser
+    syntax_search (0.1.4)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    ast (2.4.1)
     diff-lcs (1.4.4)
-    parser (2.7.2.0)
-      ast (~> 2.4.1)
     rake (12.3.3)
     rspec (3.10.0)
       rspec-core (~> 3.10.0)

lib/syntax_search.rb

@@ -2,10 +2,10 @@
 
 require_relative "syntax_search/version"
 
-require 'parser/current'
 require 'tmpdir'
 require 'stringio'
 require 'pathname'
+require 'ripper'
 
 module SyntaxErrorSearch
   class Error < StandardError; end
@@ -80,6 +80,13 @@ def self.valid_without?(without_lines: , code_lines:)
     end
   end
 
+  def self.invalid?(source)
+    source = source.join if source.is_a?(Array)
+    source = source.to_s
+
+    Ripper.new(source).tap(&:parse).error?
+  end
+
   # Returns truthy if a given input source is valid syntax
   #
   #   SyntaxErrorSearch.valid?(<<~EOM) # => true
@@ -115,38 +122,12 @@ def self.valid_without?(without_lines: , code_lines:)
   # so passing a CodeLine in as an object or as an array
   # will convert it to it's code representation.
   def self.valid?(source)
-    source = source.join if source.is_a?(Array)
-    source = source.to_s
-
-    # Parser writes to stderr even if you catch the error
-    stderr = $stderr
-    $stderr = StringIO.new
-
-    Parser::CurrentRuby.parse(source)
-    true
-  rescue Parser::SyntaxError => e
-    yield e if block_given?
-    false
-  ensure
-    $stderr = stderr if stderr
+    !invalid?(source)
   end
 
-  def self.invalid_type(source)
-    message = nil
-    self.valid?(source) do |error|
-      message = error.message
-    end
 
-    case message
-    when nil
-      :none
-    when /token kEND/
-      :unmatched_end
-    when /token \$end/ #
-      :missing_end
-    else
-      raise "Unexpected message #{message}"
-    end
+  def self.invalid_type(source)
+    WhoDisSyntaxError.new(source).call.error_symbol
   end
 end
 
@@ -159,3 +140,4 @@ def self.invalid_type(source)
 require_relative "syntax_search/parse_blocks_from_indent_line"
 
 require_relative "syntax_search/code_search"
+require_relative "syntax_search/who_dis_syntax_error"

lib/syntax_search/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module SyntaxErrorSearch
-  VERSION = "0.1.3"
+  VERSION = "0.1.4"
 end

lib/syntax_search/who_dis_syntax_error.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module SyntaxErrorSearch
+  # Determines what type of syntax error is in the source
+  #
+  # Example:
+  #
+  #   puts WhoDisSyntaxError.new("def foo;").call.error_symbol
+  #   # => :missing_end
+  class WhoDisSyntaxError < Ripper
+    attr_reader :error, :run_once, :error_symbol
+
+    def call
+      @run_once ||= begin
+        parse
+        true
+      end
+      self
+    end
+
+    def on_parse_error(msg)
+      @error = msg
+      if @error.match?(/unexpected end-of-input/)
+        @error_symbol = :missing_end
+      elsif @error.match?(/unexpected `end'/) || @error.match?(/expecting end-of-input/)
+        @error_symbol = :unmatched_end
+      else
+        @error_symbol = :nope
+      end
+    end
+  end
+end

spec/unit/who_dis_syntax_error_spec.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require_relative "../spec_helper.rb"
+
+module SyntaxErrorSearch
+  RSpec.describe WhoDisSyntaxError do
+    it  "determines the type of syntax error" do
+      expect(
+        WhoDisSyntaxError.new("def foo;").call.error_symbol
+      ).to eq(:missing_end)
+
+      expect(
+        WhoDisSyntaxError.new("def foo; end; end").call.error_symbol
+      ).to eq(:unmatched_end)
+    end
+  end
+end

syntax_search.gemspec

@@ -25,6 +25,4 @@ Gem::Specification.new do |spec|
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
-
-  spec.add_dependency "parser"
 end