Built-in types are grouped under 6 categories:

• nominal - base type definitions with a primitive class and options
• strict - constrained types with a primitive type check applied to input
• coercible - types with constructors using kernel coercions
• params - types with constructors performing non-strict coercions specific to HTTP parameters
• json - types with constructors performing non-strict coercions specific to JSON
• maybe - types accepting either nil or a specific primitive type

Categories

Assuming you included Dry::Types (see instructions) in a module called Types:

• Nominal types:

  • Types::Nominal::Any
  • Types::Nominal::Nil
  • Types::Nominal::Symbol
  • Types::Nominal::Class
  • Types::Nominal::True
  • Types::Nominal::False
  • Types::Nominal::Bool
  • Types::Nominal::Integer
  • Types::Nominal::Float
  • Types::Nominal::Decimal
  • Types::Nominal::String
  • Types::Nominal::Date
  • Types::Nominal::DateTime
  • Types::Nominal::Time
  • Types::Nominal::Array
  • Types::Nominal::Hash

• Strict types will raise an error if passed a value of the wrong type:

  • Types::Strict::Nil
  • Types::Strict::Symbol
  • Types::Strict::Class
  • Types::Strict::True
  • Types::Strict::False
  • Types::Strict::Bool
  • Types::Strict::Integer
  • Types::Strict::Float
  • Types::Strict::Decimal
  • Types::Strict::String
  • Types::Strict::Date
  • Types::Strict::DateTime
  • Types::Strict::Time
  • Types::Strict::Array
  • Types::Strict::Hash

All types in the strict category are constrained by a type-check that is applied to make sure that the input is an instance of the primitive:

Types::Strict::Integer[1] # => 1
Types::Strict::Integer['1'] # => raises Dry::Types::ConstraintError

• Coercible types will attempt to cast values to the correct class using kernel coercion methods:

  • Types::Coercible::String
  • Types::Coercible::Symbol
  • Types::Coercible::Integer
  • Types::Coercible::Float
  • Types::Coercible::Decimal
  • Types::Coercible::Array
  • Types::Coercible::Hash

• Types suitable for Params param processing with coercions:

  • Types::Params::Nil
  • Types::Params::Date
  • Types::Params::DateTime
  • Types::Params::Time
  • Types::Params::True
  • Types::Params::False
  • Types::Params::Bool
  • Types::Params::Integer
  • Types::Params::Float
  • Types::Params::Decimal
  • Types::Params::Array
  • Types::Params::Hash

• Types suitable for JSON processing with coercions:

  • Types::JSON::Nil
  • Types::JSON::Symbol
  • Types::JSON::Date
  • Types::JSON::DateTime
  • Types::JSON::Time
  • Types::JSON::Decimal
  • Types::JSON::Array
  • Types::JSON::Hash

• Maybe strict types:

  • Types::Maybe::Strict::Class
  • Types::Maybe::Strict::String
  • Types::Maybe::Strict::Symbol
  • Types::Maybe::Strict::True
  • Types::Maybe::Strict::False
  • Types::Maybe::Strict::Integer
  • Types::Maybe::Strict::Float
  • Types::Maybe::Strict::Decimal
  • Types::Maybe::Strict::Date
  • Types::Maybe::Strict::DateTime
  • Types::Maybe::Strict::Time
  • Types::Maybe::Strict::Array
  • Types::Maybe::Strict::Hash

• Maybe coercible types:

  • Types::Maybe::Coercible::String
  • Types::Maybe::Coercible::Integer
  • Types::Maybe::Coercible::Float
  • Types::Maybe::Coercible::Decimal
  • Types::Maybe::Coercible::Array
  • Types::Maybe::Coercible::Hash

Maybe types are not available by default - they must be loaded using Dry::Types.load_extensions(:maybe). See Maybe extension for more information.