diff --git a/lib/rpl/types.rb b/lib/rpl/types.rb
new file mode 100644
index 0000000..3e99c7e
--- /dev/null
+++ b/lib/rpl/types.rb
@@ -0,0 +1,184 @@
+# frozen_string_literal: true
+
+# :boolean
+class RplBoolean
+  attr_accessor :value
+
+  def initialize( value )
+    raise RplTypeError unless self.class.can_parse?( value )
+
+    @value = if value.is_a?( String )
+               value.downcase == 'true'
+             else
+               value
+             end
+  end
+
+  def to_s
+    @value.to_s
+  end
+
+  def self.can_parse?( value )
+    return %w[true false].include?( value.downcase ) if value.is_a?( String )
+
+    %w[TrueClass FalseClass].include?( value.class.to_s )
+  end
+end
+
+# :list
+class RplList
+  attr_accessor :value
+
+  def initialize( value )
+    raise RplTypeError unless self.class.can_parse?( value )
+
+    # we systematicalyl trim enclosing { }
+    @value = value[2..-3] # TODO: parse each element
+  end
+
+  def to_s
+    "{ #{@value.map(&:to_s).join(' ')} }"
+  end
+
+  def self.can_parse?( value )
+    value[0] == '{' && value[-1] == '}'
+  end
+end
+
+# :name
+class RplName
+  attr_accessor :value
+
+  def initialize( value )
+    raise RplTypeError unless self.class.can_parse?( value )
+
+    # we systematicalyl trim enclosing '
+    @value = value[1..-2]
+  end
+
+  def to_s
+    "'#{@value}'"
+  end
+
+  def self.can_parse?( value )
+    value[0] == "'" && value[-1] == "'"
+  end
+end
+
+# :numeric
+class RplNumeric
+  attr_accessor :value
+
+  def initialize( value, base = 10 )
+    raise RplTypeError unless self.class.can_parse?( value )
+
+    @base = base
+    @value = value
+
+    underscore_position = @value.index('_')
+
+    if @value[0] == '0' && ( %w[b o x].include?( @value[1] ) || !underscore_position.nil? )
+      if @value[1] == 'x'
+        @base = 16
+      elsif @value[1] == 'b'
+        @base = 2
+      elsif @value[1] == 'o'
+        @base = 8
+        @value = @value[2..-1]
+      elsif !underscore_position.nil?
+        @base = @value[1..(underscore_position - 1)].to_i
+        @value = @value[(underscore_position + 1)..-1]
+      end
+    end
+
+    @value = @value.to_i( @base ) unless @base == 10
+    @value = BigDecimal( @value, @precision ) # FIXME: how to get @precision?
+  end
+
+  def to_s
+    prefix = case @base
+             when 2
+               '0b'
+             when 8
+               '0o'
+             when 10
+               ''
+             when 16
+               '0x'
+             else
+               "0#{@base}_"
+             end
+
+    if @value.infinite?
+      suffix = @value.infinite?.positive? ? '∞' : '-∞'
+    elsif @value.nan?
+      suffix = '<NaN>'
+    else
+      suffix = if @value.to_i == @value
+                 @value.to_i
+               else
+                 @value.to_s('F')
+               end
+      suffix = @value.to_s( @base ) unless @base == 10
+    end
+
+    "#{prefix}#{suffix}"
+  end
+
+  def self.can_parse?( value )
+    # FIXME
+    !Float( value ).nil?
+  rescue ArgumentError
+    begin
+      !Integer( value ).nil?
+    rescue ArgumentError
+      false
+    end
+  end
+
+  def self.infer_resulting_base( numerics )
+    10 if numerics.length.zero?
+
+    numerics.last.base
+  end
+end
+
+# :string
+class RplString
+  attr_accessor :value
+
+  def initialize( value )
+    raise RplTypeError unless self.class.can_parse?( value )
+
+    # we systematicalyl trim enclosing "
+    @value = value[1..-2]
+  end
+
+  def to_s
+    "\"#{@value}\""
+  end
+
+  def self.can_parse?( value )
+    value[0] == '"' && value[-1] == '"'
+  end
+end
+
+# :program
+class RplProgram
+  attr_accessor :value
+
+  def initialize( value )
+    raise RplTypeError unless self.class.can_parse?( value )
+
+    # we systematicalyl trim enclosing « »
+    @value = value[2..-3]
+  end
+
+  def to_s
+    "« #{@value} »"
+  end
+
+  def self.can_parse?( value )
+    value[0] == '«' && value[-1] == '»'
+  end
+end
diff --git a/spec/types_spec.rb b/spec/types_spec.rb
new file mode 100644
index 0000000..e403245
--- /dev/null
+++ b/spec/types_spec.rb
@@ -0,0 +1,48 @@
+# coding: utf-8
+# frozen_string_literal: true
+
+require 'minitest/autorun'
+
+require 'rpl/types'
+
+class TestTypes < MiniTest::Test
+  def test_boolean
+    assert_equal true, RplBoolean.can_parse?( true )
+    assert_equal true, RplBoolean.can_parse?( false )
+    assert_equal true, RplBoolean.can_parse?( 'true' )
+    assert_equal true, RplBoolean.can_parse?( 'false' )
+    assert_equal true, RplBoolean.can_parse?( 'TRUE' )
+    assert_equal true, RplBoolean.can_parse?( 'FALSE' )
+    assert_equal false, RplBoolean.can_parse?( 'prout' )
+    assert_equal false, RplBoolean.can_parse?( 1 )
+
+    assert_equal RplBoolean, RplBoolean.new( true ).class
+    assert_equal RplBoolean, RplBoolean.new( false ).class
+    assert_equal RplBoolean, RplBoolean.new( 'true' ).class
+    assert_equal RplBoolean, RplBoolean.new( 'false' ).class
+    assert_equal RplBoolean, RplBoolean.new( 'TRUE' ).class
+    assert_equal RplBoolean, RplBoolean.new( 'FALSE' ).class
+
+    assert_equal true, RplBoolean.new( true ).value
+    assert_equal false, RplBoolean.new( false ).value
+    assert_equal true, RplBoolean.new( 'true' ).value
+    assert_equal false, RplBoolean.new( 'false' ).value
+    assert_equal true, RplBoolean.new( 'TRUE' ).value
+    assert_equal false, RplBoolean.new( 'FALSE' ).value
+  end
+
+  def test_name
+  end
+
+  def test_string
+  end
+
+  def test_program
+  end
+
+  def test_list
+  end
+
+  def test_numeric
+  end
+end