Class: Fusion::FileThunk

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

Overview

Lazy, memoized reference to a file’s value (a “thunk” / promise).

Instance Method Summary collapse

Constructor Details

#initialize(loader, abspath) ⇒ FileThunk

Returns a new instance of FileThunk.



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# File 'lib/fusion.rb', line 556

def initialize(loader, abspath)
  @loader = loader
  @abspath = abspath
  @state = :unforced # :unforced | :forcing | :done
  @value = nil
end

Instance Method Details

#force ⇒ Object 



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# File 'lib/fusion.rb', line 563

def force
  case @state
  when :done then @value
  when :forcing
    # We are already evaluating this file and were asked for it again
    # without any intervening function boundary => non-productive data cycle.
    Fusion.mkerr({"kind" => "data_cycle", "path" => @abspath})
  else
    @state = :forcing
    @value = @loader.evaluate_file(@abspath)
    @state = :done
    @value
  end
end