Class: Dhall::TypeChecker::Context

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

Instance Method Summary collapse

Constructor Details

#initialize(bindings = Hash.new([])) ⇒ Context

Returns a new instance of Context.



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# File 'lib/dhall/typecheck.rb', line 49

def initialize(bindings=Hash.new([]))
  @bindings = bindings.freeze
  freeze
end

Instance Method Details

#add(ftype) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 59

def add(ftype)
  self.class.new(@bindings.merge(
    ftype.var => [ftype.type] + @bindings[ftype.var]
  )).shift(1, ftype.var, 0)
end

#fetch(var) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 54

def fetch(var)
  @bindings[var.name][var.index] ||
    (raise TypeError, "Free variable: #{var}")
end

#shift(amount, name, min_index) ⇒ Object 



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# File 'lib/dhall/typecheck.rb', line 65

def shift(amount, name, min_index)
  self.class.new(@bindings.merge(
    Hash[@bindings.map do |var, bindings|
      [var, bindings.map { |b| b.shift(amount, name, min_index) }]
    end]
  ))
end