Class: Dry::Matcher::Evaluator

Inherits:
Object
  • Object
show all
Defined in:
lib/dry/matcher/evaluator.rb

Overview

Evaluator is used in Dry::Matcher#call block to handle different Cases

Instance Method Summary collapse

Constructor Details

#initialize(result, cases) ⇒ Evaluator

Returns a new instance of Evaluator.

Parameters:

  • result (Object)
  • cases (Hash{Symbol => Case}) 


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# File 'lib/dry/matcher/evaluator.rb', line 11

def initialize(result, cases)
  @cases = cases
  @result = result

  @unhandled_cases = @cases.keys.map(&:to_sym)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) {|v| ... } ⇒ Object

Handles method ‘name` called after one of the keys in `cases` hash given to #initialize

Parameters:

  • name (String) —

    name of the case given to #initialize in ‘cases` argument

  • args (Array) —

    pattern that would be tested for match and used to resolve result

  • block (#call) —

    callable that will processes resolved value from matched pattern

Yield Parameters:

  • v (Object) —

    resolved value

Returns:

  • (Object) —

    result of calling ‘block` on value resolved from `args` if `args` pattern was matched by the given case called `name`

Raises:

  • (NoMethodError) —

    if there was no case called ‘name` given to #initialize in `cases` hash



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# File 'lib/dry/matcher/evaluator.rb', line 48

def method_missing(name, *args, &block)
  kase = @cases.fetch(name) { return super }

  @unhandled_cases.delete name

  unless defined? @output
    kase.(@result, args) do |result|
      @output = yield(result)
    end
  end
end

Instance Method Details

#call {|_self| ... } ⇒ Object

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/dry/matcher/evaluator.rb', line 18

def call
  yield self

  ensure_exhaustive_match

  @output if defined? @output
end

#respond_to_missing?(name, _include_private = false) ⇒ Boolean

Checks whether ‘cases` given to #initialize contains one called `name`

Parameters:

  • name (String)
  • include_private (Boolean)

Returns:

  • (Boolean) 


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# File 'lib/dry/matcher/evaluator.rb', line 30

def respond_to_missing?(name, _include_private = false)
  @cases.key?(name)
end