add alias-prompt command

2 files changed, 34 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 332b6118..06a87687 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ### HEAD
 
+* Add 'alias-prompt' command.
 * Add `Pry::Prompt.add_prompt()`, `Pry::Prompt.get_prompt()`, `Pry::Prompt.alias_prompt` and
   `Pry::Prompt.remove_prompt()`, for integrating custom prompts with Pry
   ([#1628](https://github.com/pry/pry/pull/1628))
diff --git a/lib/pry/commands/alias_prompt.rb b/lib/pry/commands/alias_prompt.rb
new file mode 100644
index 00000000..1d592f8f
--- /dev/null
+++ b/lib/pry/commands/alias_prompt.rb
@@ -0,0 +1,33 @@
+class Pry
+  class Command::AliasPrompt < Pry::ClassCommand
+    match "alias-prompt"
+    group 'Input and Output'
+    description "Create an alternative alias for a prompt"
+    banner <<-BANNER
+    alias-prompt PROMPT_NAME ALIAS_PROMPT
+
+    Create an alternative alias for a prompt that can be seen from list-prompts and
+    used by the change-prompt commands.
+    BANNER
+
+    command_options argument_required: true
+
+    def process(prompt_name, alias_name)
+      if not args_ok?([prompt_name, alias_name])
+        return output.puts help
+      end
+      if prompt = Pry::Prompt.get_prompt(prompt_name)
+        Pry::Prompt.alias_prompt prompt_name, alias_name
+        output.puts "Alias '#{alias_name}' created"
+      else
+        raise Pry::CommandError, "prompt #{prompt_name} cannot be aliased because it doesn't exist."
+      end
+    end
+
+    private
+    def args_ok?(args)
+      args.size == 2 and args.all?{|s| String === s}
+    end
+    Pry::Commands.add_command(self)
+  end
+end