Class: Pione::Lang::DelegatableTable

Inherits:
Object
  • Object
show all
Defined in:
lib/pione/lang/environment.rb

Overview

DelegatableTable is a value table identified by two keys(package id and name).

Direct Known Subclasses

RuleTable, VariableTable

Instance Method Summary collapse

Constructor Details

#initialize(parent, table = Hash.new {|h, k| h[k] = Hash.new}) ⇒ DelegatableTable

Returns a new instance of DelegatableTable.



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# File 'lib/pione/lang/environment.rb', line 5

def initialize(parent, table=Hash.new {|h, k| h[k] = Hash.new})
  @parent = parent # parent delegatable table
  @table = table   # 2d table
end

Instance Method Details

#bound?(package_id, name) ⇒ Boolean

Return true if the name with the package id is bound.

Returns:

  • (Boolean) 


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# File 'lib/pione/lang/environment.rb', line 11

def bound?(package_id, name)
  (@table.has_key?(package_id) and @table[package_id][name]) || (@parent ? @parent.bound?(package_id, name) : false)
end

#dumpable ⇒ Object 



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# File 'lib/pione/lang/environment.rb', line 119

def dumpable
  parent = @parent ? @parent.dumpable : nil
  table = Hash[*@table.to_a.flatten]
  self.class.new(parent, table)
end

#get(env, ref) ⇒ Object

Find value of the reference recursively. We will raise +CircularReferenceError+ if the reference is circular.



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# File 'lib/pione/lang/environment.rb', line 17

def get(env, ref)
  history = [ref.package_id, ref.name]

  # detect reference loop
  if env.reference_history.include?(history)
    raise CircularReferenceError.new(ref)
  end

  # push package id and name to history
  _env = env.set(reference_history: env.reference_history + [history])

  # get the expression and evaluate it
  if expr = get_value(env, ref)
    evaluate_value(_env, expr)
  else
    raise UnboundError.new(ref)
  end
end

#get!(env, ref) ⇒ Object 



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# File 'lib/pione/lang/environment.rb', line 36

def get!(env, ref)
  get(env, ref)
rescue UnboundError
  nil
end

#get_value(env, ref) ⇒ Object

Get the value expression corresponding to the reference in the table. This method is not circular.



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# File 'lib/pione/lang/environment.rb', line 44

def get_value(env, ref)
  unless ref.package_id
    raise ArgumentError.new("package id is invalid: %s" % ref.inspect)
  end

  # when it is known reference
  if expr = @table[ref.package_id][ref.name]
    return expr
  end

  if bound?(ref.package_id, ref.name)
    # get value from parent table
    return @parent.get_value(env, ref) if @parent
  else
    # otherwise, find by parent package id
    env.find_ancestor_ids(ref.package_id).each do |ancestor_id|
      if val = get_value(env, ref.set(package_id: ancestor_id))
        return val
      end
    end
  end

  return nil
end

#inspect ⇒ Object 



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# File 'lib/pione/lang/environment.rb', line 111

def inspect
  if @parent
    "#%s(%s,%s)" % [self.class.name.split("::").last, @table, @parent.inspect]
  else
    "#%s(%s)" % [self.class.name.split("::").last, @table]
  end
end

#keys ⇒ Object

Return all reference in the table and the parent.



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# File 'lib/pione/lang/environment.rb', line 86

def keys
  @table.keys.inject(@parent ? @parent.keys : []) do |res, k1|
    @table[k1].keys.inject(res) do |_res, k2|
      ref = make_reference(k1, k2)
      _res.include?(ref) ? _res : res << ref
    end
  end
end

#select_names_by(env, package_id) ⇒ Array<String>

Return all names that related to the package ID and ancestors.

Returns:

  • (Array<String>) —

    all names in the table



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# File 'lib/pione/lang/environment.rb', line 99

def select_names_by(env, package_id)
  names = @parent ? @parent.select_names_by(package_id) : []
  target_ids = [package_id, *env.find_ancestor_ids(package_id)]
  target_ids.each_with_object(names) do |target_id, names|
    @table[target_id].keys.each do |name|
      if not(names.include?(name))
        names << name
      end
    end
  end
end

#set(ref, val) ⇒ Object

Update table with the name and value. We will raise +RebindError+ if the reference is bound already.



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# File 'lib/pione/lang/environment.rb', line 71

def set(ref, val)
  unless bound?(ref.package_id, ref.name)
    set!(ref, val)
  else
    raise RebindError.new(ref)
  end
end

#set!(ref, val) ⇒ Object

Update the table with the name and value. This method permits to overwrite the value, so you can ignore +RebindError+.



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# File 'lib/pione/lang/environment.rb', line 81

def set!(ref, val)
  @table[ref.package_id][ref.name] = val
end