```ruby
# coding: utf-8
lib = File.expand_path("../lib", __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require "lasp/version"

Gem::Specification.new do |spec|
  spec.name          = "lasp"
  spec.version       = Lasp::VERSION
  spec.authors       = ["Jimmy Börjesson"]
  spec.email         = ["lagginglion@gmail.com"]

  spec.summary       = "A simple Lisp-dialect programming language inspired by Clojure."
  spec.homepage      = "https://github.com/alcesleo/lasp"
  spec.license       = "MIT"

  spec.files         = `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
  spec.bindir        = "bin"
  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
  spec.require_paths = ["lib"]

  spec.required_ruby_version = "~> 2.0"

  spec.add_development_dependency "bundler", "~> 1.7"
  spec.add_development_dependency "rake", "~> 10.0"
  spec.add_development_dependency "rspec", "~> 3.4"
  spec.add_development_dependency "rubocop", "~> 0.38"
end
```

Use plain Ruby to select files in gemspec
user
```ruby
# coding: utf-8
lib = File.expand_path("../lib", __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require "lasp/version"

Gem::Specification.new do |spec|
  spec.name          = "lasp"
  spec.version       = Lasp::VERSION
  spec.authors       = ["Jimmy Börjesson"]
  spec.email         = ["lagginglion@gmail.com"]

  spec.summary       = "A simple Lisp-dialect programming language inspired by Clojure."
  spec.homepage      = "https://github.com/alcesleo/lasp"
  spec.license       = "MIT"

  spec.files         = Dir.glob("{bin,docs,lib,spec}/**/*")
  spec.files        += %w(LICENSE.txt README.md CHANGELOG.md Rakefile lasp.gemspec)

  spec.bindir        = "bin"
  spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
  spec.require_paths = ["lib"]

  spec.required_ruby_version = "~> 2.0"

  spec.add_development_dependency "bundler", "~> 1.7"
  spec.add_development_dependency "rake", "~> 10.0"
  spec.add_development_dependency "rspec", "~> 3.4"
  spec.add_development_dependency "rubocop", "~> 0.38"
end
```
assistant