struct Monads::Nothing(T)

Defined in:

monads/maybe.cr

Constructors

Instance Method Summary

Instance methods inherited from struct Monads::Maybe(T)

<=>(other : Nothing)
<=>(other : Just) <=>, inspect(io) inspect, just? just?, map_or(default : U, lambda : T -> U) forall U
map_or(default : U, &block : T -> U) forall U map_or, nothing? nothing?, or(default : Maybe)
or(lambda : -> _)
or(&block : -> U) forall U or, to_s to_s, value_or(default : U) forall U
value_or(&block : E -> U) forall U value_or

Constructor methods inherited from struct Monads::Maybe(T)

new new

Class methods inherited from struct Monads::Maybe(T)

return(v : T) return

Instance methods inherited from struct Monads::Monad(T)

>>(other : Monad(U)) forall U >>, |(other : _ -> Monad(U)) forall U |, bind(lambda : T -> Monad(U)) forall U
bind(&block : T -> Monad(U)) forall U bind

Constructor methods inherited from struct Monads::Monad(T)

new new, return(v : T) : self return

Instance methods inherited from struct Monads::Functor(T)

fmap(lambda : T -> U)
fmap(&block : T -> U) forall U fmap, initialize initialize

Constructor methods inherited from struct Monads::Functor(T)

new new

Constructor Detail

def self.new #

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Instance Method Detail

def <=>(other : Nothing) #
Description copied from module Comparable(Monads::Maybe(T))

The comparison operator. Returns 0 if the two objects are equal, a negative number if this object is considered less than other, a positive number if this object is considered greater than other, or nil if the two objects are not comparable.

Subclasses define this method to provide class-specific ordering.

The comparison operator is usually used to sort values:

# Sort in a descending way:
[3, 1, 2].sort { |x, y| y <=> x } # => [3, 2, 1]

# Sort in an ascending way:
[3, 1, 2].sort { |x, y| x <=> y } # => [1, 2, 3]

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def <=>(other : Just) #
Description copied from module Comparable(Monads::Maybe(T))

The comparison operator. Returns 0 if the two objects are equal, a negative number if this object is considered less than other, a positive number if this object is considered greater than other, or nil if the two objects are not comparable.

Subclasses define this method to provide class-specific ordering.

The comparison operator is usually used to sort values:

# Sort in a descending way:
[3, 1, 2].sort { |x, y| y <=> x } # => [3, 2, 1]

# Sort in an ascending way:
[3, 1, 2].sort { |x, y| x <=> y } # => [1, 2, 3]

[View source]
def <=>(other : Maybe) #
Description copied from module Comparable(Monads::Maybe(T))

The comparison operator. Returns 0 if the two objects are equal, a negative number if this object is considered less than other, a positive number if this object is considered greater than other, or nil if the two objects are not comparable.

Subclasses define this method to provide class-specific ordering.

The comparison operator is usually used to sort values:

# Sort in a descending way:
[3, 1, 2].sort { |x, y| y <=> x } # => [3, 2, 1]

# Sort in an ascending way:
[3, 1, 2].sort { |x, y| x <=> y } # => [1, 2, 3]

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def bind(lambda : _ -> Maybe(U)) forall U #

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def fmap(lambda : _ -> U) forall U #

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def map_or(default : U, lambda : _ -> _) forall U #

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def or(default : Maybe) #

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def or(lambda : -> _) #

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def to_s #
Description copied from class Object

Returns a nicely readable and concise string representation of this object, typically intended for users.

This method should usually not be overridden. It delegates to #to_s(IO) which can be overridden for custom implementations.

Also see #inspect.


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def value_or(default : U) forall U #

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