[ruby/irb] `show_doc` command should take non-string argument too

(https://github.com/ruby/irb/pull/478)

Given that `show_doc` already supports syntax like `String#gsub`, it
should be able to take it in non-string form too, like `edit` and
`show_source` do. This ensures users can have a consistent syntax on
argument between different commands.

4 files changed, 18 insertions, 12 deletions

diff --git a/lib/irb/cmd/edit.rb b/lib/irb/cmd/edit.rb
index 98fa07e49d..0103891cf4 100644
--- a/lib/irb/cmd/edit.rb
+++ b/lib/irb/cmd/edit.rb
@@ -18,13 +18,6 @@ module IRB
             args.strip.dump
           end
         end
-
-        private
-
-        def string_literal?(args)
-          sexp = Ripper.sexp(args)
-          sexp && sexp.size == 2 && sexp.last&.first&.first == :string_literal
-        end
       end
 
       def execute(*args)
diff --git a/lib/irb/cmd/help.rb b/lib/irb/cmd/help.rb
index 3ef59f5eea..2a135cdb14 100644
--- a/lib/irb/cmd/help.rb
+++ b/lib/irb/cmd/help.rb
@@ -16,6 +16,17 @@ module IRB
 
   module ExtendCommand
     class Help < Nop
+      class << self
+        def transform_args(args)
+          # Return a string literal as is for backward compatibility
+          if args.empty? || string_literal?(args)
+            args
+          else # Otherwise, consider the input as a String for convenience
+            args.strip.dump
+          end
+        end
+      end
+
       category "Context"
       description "Enter the mode to look up RI documents."
 
diff --git a/lib/irb/cmd/nop.rb b/lib/irb/cmd/nop.rb
index 32074f2d9f..c616c054a8 100644
--- a/lib/irb/cmd/nop.rb
+++ b/lib/irb/cmd/nop.rb
@@ -26,6 +26,13 @@ module IRB
           @description = description if description
           @description
         end
+
+        private
+
+        def string_literal?(args)
+          sexp = Ripper.sexp(args)
+          sexp && sexp.size == 2 && sexp.last&.first&.first == :string_literal
+        end
       end
 
       if RUBY_ENGINE == "ruby" && RUBY_VERSION >= "2.7.0"
diff --git a/lib/irb/cmd/show_source.rb b/lib/irb/cmd/show_source.rb
index b68aa257c2..ea700be4bf 100644
--- a/lib/irb/cmd/show_source.rb
+++ b/lib/irb/cmd/show_source.rb
@@ -65,11 +65,6 @@ module IRB
           end
           first_line
         end
-
-        def string_literal?(args)
-          sexp = Ripper.sexp(args)
-          sexp && sexp.size == 2 && sexp.last&.first&.first == :string_literal
-        end
       end
 
       def execute(str = nil)