Rdb: Ruby-Nachbau der MWC /rdb-Werkzeuge

lib/rdb.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+# A Ruby re-creation of /rdb, the relational database tools Mark Williams
+# Company sold for COHERENT (~1991).
+
+require 'open3'
+require 'date'
+require 'tmpdir'
+require 'fileutils'
+
+module Rdb
+  ROOT = File.expand_path('..', __dir__)
+  NUM = /\A\s*[+-]?(\d+\.?\d*|\.\d+)\s*\z/
+
+  Command = Struct.new(:name, :desc, :syntax, :block)
+  COMMANDS = {}
+
+  class << self
+    def die(msg)
+      abort "#{File.basename($PROGRAM_NAME)}: #{msg}"
+    end
+
+    # register 'name', 'description', 'syntax' do |args| ... end
+    def register(name, desc, syntax = nil, &block)
+      COMMANDS[name] = Command.new(name, desc, syntax || name, block)
+    end
+
+    def alias_for(name, target)
+      cmd = COMMANDS.fetch(target)
+      COMMANDS[name] = Command.new(name, cmd.desc, cmd.syntax.sub(target, name), cmd.block)
+    end
+
+    def run(name, args)
+      cmd = COMMANDS[name] or die("unknown command '#{name}'")
+      Env.new(name).instance_exec(args.dup, &cmd.block)
+    end
+  end
+end
+
+require_relative 'rdb/table'
+require_relative 'rdb/env'
+Dir[File.join(__dir__, 'rdb/cmd/*.rb')].sort.each { |f| require f }