Fix match_pattern{,_p}

Changelog.md

@@ -1,3 +1,9 @@
+# v0.6.2 2022-02-05
+
+[#297](https://github.com/mbj/unparser/pull/297)
+
+* Fix emit of of `match_pattern` vs `match_pattern_p`
+
 # v0.6.3 2022-01-16
 
 [#290](https://github.com/mbj/unparser/pull/290)

config/mutant.yml

@@ -10,9 +10,9 @@ matcher:
   ignore:
   # API changed between ruby versions and each of them
   # have a different minimal form
-  - 'Unparser::Concord#define_readers'
   - 'Unparser::Builder#initialize'
   - 'Unparser::CLI*'
+  - 'Unparser::Concord#define_readers'
   - 'Unparser::Emitter#emit_comments'
   - 'Unparser::Emitter#emit_comments_before'
   - 'Unparser::Emitter#emit_eol_comments'
@@ -28,6 +28,8 @@ matcher:
   - 'Unparser::Emitter::HashPattern#write_symbol_body'
   - 'Unparser::Emitter::LocalVariableRoot*'
   - 'Unparser::Emitter::LocalVariableRoot.included'
+  - 'Unparser::Emitter::MatchPattern#dispatch' # 2.7+ specific
+  - 'Unparser::Emitter::MatchPatternP#dispatch' # 3.0+ specific
   - 'Unparser::Emitter::Module#local_variable_scope'
   - 'Unparser::Emitter::Root#local_variable_scope'
   - 'Unparser::Emitter::Send#writer'

lib/unparser.rb

@@ -219,6 +219,7 @@ def self.buffer(source, identification = '(string)')
 require 'unparser/emitter/kwargs'
 require 'unparser/emitter/pair'
 require 'unparser/emitter/match_pattern'
+require 'unparser/emitter/match_pattern_p'
 require 'unparser/writer'
 require 'unparser/writer/binary'
 require 'unparser/writer/dynamic_string'

lib/unparser/emitter/match_pattern.rb

@@ -6,17 +6,25 @@ class Emitter
     class MatchPattern < self
 
       handle :match_pattern
-      handle :match_pattern_p
 
       children :target, :pattern
 
+      # Modern ast format emits `match_pattern`
+      # node on single line pre 3.0, but 3.0+ uses `match_pattern_p`
+      SYMBOL =
+        if RUBY_VERSION < '3.0'
+          ' in '
+        else
+          ' => '
+        end
+
     private
 
       def dispatch
         visit(target)
-        write(' in ')
+        write(SYMBOL)
         visit(pattern)
       end
-    end # InPattern
+    end # MatchPattern
   end # Emitter
 end # Unparser

lib/unparser/emitter/match_pattern_p.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module Unparser
+  class Emitter
+    class MatchPatternP < self
+
+      handle :match_pattern_p
+
+      children :target, :pattern
+
+    private
+
+      def dispatch
+        visit(target)
+        write(' in ')
+        visit(pattern)
+      end
+    end # MatchPatternP
+  end # Emitter
+end # Unparser

spec/unit/unparser_spec.rb

@@ -359,6 +359,14 @@ def noop
     let(:version_excludes) do
       excludes = []
 
+      if RUBY_VERSION < '3.0.'
+        excludes.concat(
+          %w[
+            test/corpus/literal/since/30.rb
+          ]
+        )
+      end
+
       if RUBY_VERSION < '2.7.'
         excludes.concat(
           %w[

test/corpus/literal/since/30.rb

@@ -0,0 +1,2 @@
+1 => [a]
+1 => [*]