module T
Namespaces without any implementation
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Docs at sorbet.org/docs/sigs
Types
that you can pass to `sig`:
- a Ruby class - [<Type>, <Type>, ...] -- to specify a "tuple"; a fixed-size array with known types for each member - {key: <Type>, key2: <Type>, ...} -- to speicfy a "shape"; a fixed-size hash with known keys and type values - Any of the `T.foo` methods below
typed: strict
Work around for sorbet-runtime wrapped methods.
When a sig is defined, sorbet-runtime will replace the sigged method with a wrapper. Those wrapper methods look like `foo(*args, &blk)` so that wrappers can handle and pass on all the arguments supplied.
However, that creates a problem with runtime reflection on the methods, since when a sigged method is introspected, it will always return its `arity` as `-1`, its `parameters` as `[[:rest, :args], [:block, :blk]]`, and its `source_location` as `[<some_file_in_sorbet>, <some_line_number>]`.
This might be a problem for some applications that rely on getting the correct information from these methods.
This compatibility module, when prepended to the `Method` class, would fix the return values of `arity`, `parameters` and `source_location`.
@example
require 'sorbet-runtime' ::Method.prepend(T::CompatibilityPatches::MethodExtensions)
Constants
- Boolean
T::Boolean
is a type alias helper for the common `T.any(TrueClass, FalseClass)`. Defined separately from _types.rb because it has a dependency onT::Types::Union
.
Public Class Methods
A way to ask Sorbet to prove that a certain branch of control flow never happens. Commonly used to assert that a case or if statement exhausts all possible cases.
# File lib/types/_types.rb, line 231 def self.absurd(value) msg = "Control flow reached T.absurd." case value when Kernel msg += " Got value: #{value}" end begin raise TypeError.new(msg) rescue TypeError => e # raise into rescue to ensure e.backtrace is populated T::Configuration.inline_type_error_handler(e) end end
T.all
(<Type>, <Type>, …) – matches an object that has all of the types listed
# File lib/types/_types.rb, line 51 def self.all(type_a, type_b, *types) T::Types::Intersection.new([type_a, type_b] + types) end
T.any
(<Type>, <Type>, …) – matches any of the types listed
# File lib/types/_types.rb, line 27 def self.any(type_a, type_b, *types) type_a = T::Utils.coerce(type_a) type_b = T::Utils.coerce(type_b) types = types.map {|t| T::Utils.coerce(t)} if !types.empty? T::Types::Union::Private::Pool.union_of_types(type_a, type_b, types) end
Tells the typechecker to ensure that `value` is of type `type` (if not, the typechecker will fail). Use this for debugging typechecking errors, or to ensure that type information is statically known and being checked appropriately. If `checked` is true, raises an exception at runtime if the value doesn't match the type.
# File lib/types/_types.rb, line 171 def self.assert_type!(value, type, checked: true) return value unless checked Private::Casts.cast(value, type, cast_method: "T.assert_type!") end
Matches the instance type in a singleton-class context
# File lib/types/_types.rb, line 71 def self.attached_class T::Types::AttachedClassType::Private::INSTANCE end
Tells the type checker to treat `self` in the current block as `type`. Useful for blocks that are captured and executed later with instance_exec. Use like:
seconds = lambda do T.bind(self, NewBinding) ... end
`T.bind` behaves like `T.cast` in that it is assumed to be true statically.
If `checked` is true, raises an exception at runtime if the value doesn't match the type (this is the default).
# File lib/types/_types.rb, line 161 def self.bind(value, type, checked: true) return value unless checked Private::Casts.cast(value, type, cast_method: "T.bind") end
Tells the typechecker that `value` is of type `type`. Use this to get additional checking after an expression that the typechecker is unable to analyze. If `checked` is true, raises an exception at runtime if the value doesn't match the type.
Compared to `T.let`, `T.cast` is trusted by static system.
# File lib/types/_types.rb, line 127 def self.cast(value, type, checked: true) return value unless checked Private::Casts.cast(value, type, cast_method: "T.cast") end
Matches any class that subclasses or includes the provided class or module
# File lib/types/_types.rb, line 77 def self.class_of(klass) T::Types::ClassOf.new(klass) end
Matches any of the listed values
# File lib/types/_types.rb, line 56 def self.enum(values) T::Types::Enum.new(values) end
Tells the typechecker to declare a variable of type `type`. Use like:
seconds = T.let(0.0, Float)
Compared to `T.cast`, `T.let` is checked by static system.
If `checked` is true, raises an exception at runtime if the value doesn't match the type.
# File lib/types/_types.rb, line 142 def self.let(value, type, checked: true) return value unless checked Private::Casts.cast(value, type, cast_method: "T.let") end
A convenience method to `raise` when the argument is `nil` and return it otherwise.
Intended to be used as:
needs_foo(T.must(maybe_gives_foo))
Equivalent to:
foo = maybe_gives_foo raise "nil" if foo.nil? needs_foo(foo)
Intended to be used to promise sorbet that a given nilable value happens to contain a non-nil value at this point.
sig {params(arg: T.nilable(A)
).returns(A)}
# File lib/types/_types.rb, line 210 def self.must(arg) return arg if arg return arg if arg == false begin raise TypeError.new("Passed `nil` into T.must") rescue TypeError => e # raise into rescue to ensure e.backtrace is populated T::Configuration.inline_type_error_handler(e) end end
Shorthand for T.any
(type, NilClass)
# File lib/types/_types.rb, line 35 def self.nilable(type) T::Types::Union::Private::Pool.union_of_types(T::Utils.coerce(type), T::Utils::Nilable::NIL_TYPE) end
Indicates a function never returns (e.g. “Kernel#raise”)
# File lib/types/_types.rb, line 46 def self.noreturn T::Types::NoReturn::Private::INSTANCE end
Creates a proc type
# File lib/types/_types.rb, line 61 def self.proc T::Private::Methods.start_proc end
A way to ask Sorbet to show what type it thinks an expression has. This can be useful for debugging and checking assumptions. In the runtime, merely returns the value passed in.
# File lib/types/_types.rb, line 224 def self.reveal_type(value) value end
Matches `self`:
# File lib/types/_types.rb, line 66 def self.self_type T::Types::SelfType::Private::INSTANCE end
Constructs a type alias. Used to create a short name for a larger type. In Ruby this returns a wrapper that contains a proc that is evaluated to get the underlying type. This syntax however is needed for support by the static checker. Example usage:
NilableString = T.type_alias {T.nilable(String)} sig {params(arg: NilableString, default: String).returns(String)} def or_else(arg, default) arg || default end
The name of the type alias is not preserved; Error messages will be printed with reference to the underlying type.
TODO Remove `type` parameter. This was left in to make life easier while migrating.
# File lib/types/_types.rb, line 98 def self.type_alias(type=nil, &blk) if blk T::Private::Types::TypeAlias.new(blk) else T::Utils.coerce(type) end end
References a type parameter which was previously defined with `type_parameters`.
This is used for generic methods. Example usage:
sig .type_parameters(:U) .params( blk: T.proc.params(arg0: Elem).returns(T.type_parameter(:U)), ) .returns(T::Array[T.type_parameter(:U)]) def map(&blk); end
# File lib/types/_types.rb, line 118 def self.type_parameter(name) T::Types::TypeParameter.new(name) end
For the static type checker, strips all type information from a value and returns the same value, but statically-typed as `T.untyped`. Can be used to tell the static checker to “trust you” by discarding type information you know to be incorrect. Use with care! (This has no effect at runtime.)
We can't actually write this sig because we ourselves are inside the `T::` module and doing this would create a bootstrapping cycle. However, we also don't actually need to do so; An untyped identity method works just as well here.
sig {params(value: T.untyped
).returns(T.untyped
)}
# File lib/types/_types.rb, line 189 def self.unsafe(value) value end
Matches any object. In the static checker, T.untyped
allows any method calls or operations.
# File lib/types/_types.rb, line 41 def self.untyped T::Types::Untyped::Private::INSTANCE end