Class: MonadOxide::Ok

Inherits:
Result
  • Object
show all
Defined in:
lib/ok.rb

Overview

‘Ok’ represents a success ‘Result’. For most operations, ‘Ok’ will perform some operation. Exceptions raised during calls to ‘Ok’ will coerce the chain into ‘Err’, which generally causes execution to fall through the entire chain.

Instance Method Summary collapse

Methods inherited from Result

#flatten, #match

Constructor Details

#initialize(data) ⇒ Ok

Constructs an ‘Ok’ with the data provided.

Parameters:

  • data (Object) —

    The inner data this Result encapsulates.



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# File 'lib/ok.rb', line 13

def initialize(data)
  @data = data
end

Instance Method Details

#and_then(f = nil) { ... } ⇒ Ok<B> | Err<C>

Invokes ‘f’ or the block with the data and returns the Result returned from that. Exceptions raised during ‘f’ or the block will return an ‘Err<Exception>’. The return type is enforced.

Parameters:

  • f (Proc<A, Result<B>>) (defaults to: nil) —

    The function to call. Could be a block instead. Takes an [A=Object] and must return a [Result<B>].

Yields:

  • Will yield a block that takes an A and returns a Result<B>. Same as ‘f’ parameter.

Returns:

  • (Ok<B> | Err<C>) —

    A new Result from ‘f’ or the block. Exceptions raised will result in ‘Err<C>’. If ‘f’ returns a non-Result, this will return ‘Err<ResultReturnExpectedError>’.



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# File 'lib/ok.rb', line 28

def and_then(f=nil, &block)
  begin
    r = (f || block).call(@data)
    # Enforce that we always get a Result. Without a Result, coerce to an
    # Err.
    if !r.kind_of?(Result)
      raise ResultReturnExpectedError.new(r)
    else
      r
    end
  rescue => e
    Err.new(e)
  end
end

#inspect_err(f = nil) { ... } ⇒ Ok

Falls through. @see Result#inspect_err for how this is handled in either Result case, and @see Err.inspect_err for how this is handled in the Err case.

Parameters:

  • f (Proc) (defaults to: nil) —

    Optional Proc - ignored.

Yields:

  • An ignored block.

Returns:

  • (Ok) —

    This Ok.



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# File 'lib/ok.rb', line 50

def inspect_err(f=nil, &block)
  self
end

#inspect_ok(f = nil) { ... } ⇒ Result<A>

Applies ‘f’ or the block over the data and returns the same ‘Ok’. No changes are applied. This is ideal for logging. Exceptions raised during these transformations will return an ‘Err’ with the Exception.

Parameters:

  • f (Proc<A, B>) (defaults to: nil) —

    The function to call. Could be a block instead. Takes an [A] the return is ignored.

Yields:

  • Will yield a block that takes an A the return is ignored. Same as ‘f’ parameter.

Returns:

  • (Result<A>) —

    returns self.



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# File 'lib/ok.rb', line 63

def inspect_ok(f=nil, &block)
  begin
    (f || block).call(@data)
    self
  rescue => e
    Err.new(e)
  end
end

#map(f = nil) { ... } ⇒ Result<B>

Applies ‘f’ or the block over the data and returns a new new ‘Ok’ with the returned value.

Parameters:

  • f (Proc<A, B>) (defaults to: nil) —

    The function to call. Could be a block instead. Takes an [A=Object] and returns a B.

Yields:

  • Will yield a block that takes an A and returns a B. Same as ‘f’ parameter.

Returns:

  • (Result<B>) —

    A new ‘Ok<B>’ whose ‘B’ is the return of ‘f’ or the block. Errors raised when applying ‘f’ or the block will result in a returned ‘Err<Exception>’.



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# File 'lib/ok.rb', line 82

def map(f=nil, &block)
  begin
    self.class.new((f || block).call(@data))
  rescue => e
    Err.new(e)
  end
end

#map_err(f = nil) { ... } ⇒ Result<A>

This is a no-op for Ok. @see Err#map_err.

Parameters:

  • f (Proc<A, B>) (defaults to: nil) —

    A dummy function. Not used.

Yields:

  • A dummy block. Not used.

Returns:

  • (Result<A>) —

    This ‘Ok’.



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# File 'lib/ok.rb', line 95

def map_err(f=nil, &block)
  self
end

#or_else(f = nil) { ... } ⇒ Result<A>

The Err equivalent to Ok#and_then. This is a no-op for Ok. @see Err#or_else.

Parameters:

  • f (Proc<A, B>) (defaults to: nil) —

    A dummy function. Not used.

Yields:

  • A dummy block. Not used.

Returns:

  • (Result<A>) —

    This ‘Ok’.



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# File 'lib/ok.rb', line 105

def or_else(f=nil, &block)
  self
end

#unwrap ⇒ A

Dangerously access the ‘Ok’ data. If this is an ‘Err’, an exception will be raised. It is recommended to use this for tests only.

Returns:

  • (A) —

    The inner data of this ‘Ok’.



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# File 'lib/ok.rb', line 113

def unwrap()
  @data
end

#unwrap_err ⇒ E

Dangerously access the ‘Err’ data. If this is an ‘Ok’, an exception will be raised. It is recommended to use this for tests only.

Returns:

  • (E) —

    The ‘Exception’ of this ‘Err’.

Raises:



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# File 'lib/ok.rb', line 121

def unwrap_err()
  raise UnwrapError.new(
    "#{self.class} with #{@data.inspect} could not be unwrapped as an Err.",
  )
end

#unwrap_or(_) ⇒ A

Safely unwrap the ‘Result`. In the case of `Ok`, this returns the data in the Ok.

Parameters:

  • x (B) —

    The value that will be returned.

Returns:

  • (A) —

    The data in the Ok.



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# File 'lib/ok.rb', line 133

def unwrap_or(_)
  @data
end