More specific error messages

As mentioned in #8 (comment) there are two types of syntax errors that can be hit involving an end:

- It's got and end but wasn't expecting one (unmatched end)
- It needs an end but doesn't have one (missing end)

To make this more clear, the output of SyntaxSearch now specializes for these two cases and gives a helpful output with more context.

Author: schneems

lib/syntax_search.rb

@@ -23,7 +23,7 @@ def self.handle_error(e, search_source_on_error: SEARCH_SOURCE_ON_ERROR_DEFAULT)
       self.call(
         source: Pathname(filename).read,
         filename: filename,
-        terminal: true
+        terminal: true,
       )
     end
 
@@ -40,6 +40,7 @@ def self.call(source: , filename: , terminal: false, record_dir: nil)
       blocks: blocks,
       filename: filename,
       terminal: terminal,
+      invalid_type: invalid_type(source),
       io: $stderr
     ).call
   end
@@ -122,11 +123,30 @@ def self.valid?(source)
 
     Parser::CurrentRuby.parse(source)
     true
-  rescue Parser::SyntaxError
+  rescue Parser::SyntaxError => e
+    yield e if block_given?
     false
   ensure
     $stderr = stderr if stderr
   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
+  end
 end
 
 require_relative "syntax_search/code_line"

lib/syntax_search/display_invalid_blocks.rb

@@ -5,7 +5,7 @@ module SyntaxErrorSearch
   class DisplayInvalidBlocks
     attr_reader :filename
 
-    def initialize(blocks:, io: $stderr, filename: nil, terminal: false)
+    def initialize(blocks:, io: $stderr, filename: nil, terminal: false, invalid_type: :unmatched_end)
       @terminal = terminal
       @filename = filename
       @io = io
@@ -16,6 +16,7 @@ def initialize(blocks:, io: $stderr, filename: nil, terminal: false)
       @digit_count = @code_lines.last&.line_number.to_s.length
 
       @invalid_line_hash = @lines.each_with_object({}) {|line, h| h[line] = true  }
+      @invalid_type = invalid_type
     end
 
     def call
@@ -33,15 +34,28 @@ def call
     end
 
     private def found_invalid_blocks
-      @io.puts <<~EOM
+      case @invalid_type
+      when :missing_end
+        @io.puts <<~EOM
 
-        SyntaxErrorSearch: A syntax error was detected
+          SyntaxSearch: Missing `end` detected
 
-        This code has an unmatched `end` this is caused by either
-        missing a syntax keyword (`def`,  `do`, etc.) or inclusion
-        of an extra `end` line
+          This code has a missing `end`. Ensure that all
+          syntax keywords (`def`, `do`, etc.) have a matching `end`.
+
+        EOM
+      when :unmatched_end
+        @io.puts <<~EOM
+
+          SyntaxSearch: Unmatched `end` detected
+
+          This code has an unmatched `end`. Ensure that all `end` lines
+          in your code have a matching syntax keyword  (`def`,  `do`, etc.)
+          and that you don't have any extra `end` lines.
+
+        EOM
+      end
 
-      EOM
       @io.puts("file: #{filename}") if filename
       @io.puts <<~EOM
         simplified:

spec/unit/display_invalid_blocks_spec.rb

@@ -42,7 +42,7 @@ def hai
       )
       display.call
       expect(io.string).to include("❯ 2    def hello")
-      expect(io.string).to include("A syntax error was detected")
+      expect(io.string).to include("SyntaxSearch")
     end
 
     it " wraps code with github style codeblocks" do

spec/unit/exe_spec.rb

@@ -22,7 +22,7 @@ def exe(cmd)
       ruby_file = fixtures_dir.join("this_project_extra_def.rb.txt")
       out = exe("#{ruby_file} --no-terminal")
 
-      expect(out.strip).to include("A syntax error was detected")
+      expect(out.strip).to include("Missing `end` detected")
       expect(out.strip).to include("❯ 36      def filename")
     end
 
@@ -37,7 +37,7 @@ def exe(cmd)
 
         out = exe("#{ruby_file} --record #{tmp_dir}")
 
-        expect(out.strip).to include("A syntax error was detected")
+        expect(out.strip).to include("Unmatched `end` detected")
         expect(tmp_dir).to_not be_empty
       end
     end

spec/unit/syntax_search_spec.rb

@@ -32,7 +32,7 @@ module SyntaxErrorSearch
 
         out = `ruby -I#{lib_dir} -rsyntax_search/auto #{require_rb} 2>&1`
 
-        expect(out).to include("This code has an unmatched")
+        expect(out).to include("Unmatched `end` detected")
         expect(out).to include("Run `$ syntax_search")
         expect($?.success?).to be_falsey
       end