Class: Dentaku::Calculator

Inherits:
Object
  • Object
show all
Includes:
StringCasing
Defined in:
lib/dentaku/calculator.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from StringCasing

#standardize_case

Constructor Details

#initialize(case_sensitive: false, aliases: nil, nested_data_support: true, raw_date_literals: true, ast_cache: {}, cache_ast: nil, cache_dependency_order: nil) ⇒ Calculator

Returns a new instance of Calculator.



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# File 'lib/dentaku/calculator.rb', line 15

def initialize(case_sensitive: false, aliases: nil, nested_data_support: true,
               raw_date_literals: true, ast_cache: {},
               cache_ast: nil, cache_dependency_order: nil)
  clear
  @tokenizer = Tokenizer.new
  @case_sensitive = case_sensitive
  @aliases = aliases
  @nested_data_support = nested_data_support
  @raw_date_literals = raw_date_literals
  @ast_cache = ast_cache
  @cache_ast = cache_ast
  @cache_dependency_order = cache_dependency_order
  @disable_ast_cache = false
  @function_registry = Dentaku::AST::FunctionRegistry.new
end

Instance Attribute Details

#ast_cache ⇒ Object (readonly)

Returns the value of attribute ast_cache.



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# File 'lib/dentaku/calculator.rb', line 12

def ast_cache
  @ast_cache
end

#case_sensitive ⇒ Object (readonly)

Returns the value of attribute case_sensitive.



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# File 'lib/dentaku/calculator.rb', line 12

def case_sensitive
  @case_sensitive
end

#memory ⇒ Object (readonly)

Returns the value of attribute memory.



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# File 'lib/dentaku/calculator.rb', line 12

def memory
  @memory
end

#nested_data_support ⇒ Object (readonly)

Returns the value of attribute nested_data_support.



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# File 'lib/dentaku/calculator.rb', line 12

def nested_data_support
  @nested_data_support
end

#raw_date_literals ⇒ Object (readonly)

Returns the value of attribute raw_date_literals.



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# File 'lib/dentaku/calculator.rb', line 12

def raw_date_literals
  @raw_date_literals
end

#result ⇒ Object (readonly)

Returns the value of attribute result.



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# File 'lib/dentaku/calculator.rb', line 12

def result
  @result
end

#tokenizer ⇒ Object (readonly)

Returns the value of attribute tokenizer.



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# File 'lib/dentaku/calculator.rb', line 12

def tokenizer
  @tokenizer
end

Class Method Details

.add_function(name, type, body, callback = nil, volatile: false) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 37

def self.add_function(name, type, body, callback = nil, volatile: false)
  Dentaku::AST::FunctionRegistry.default.register(name, type, body, callback, volatile: volatile)
end

.add_functions(functions) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 41

def self.add_functions(functions)
  functions.each { |(name, type, body, callback, volatile)| add_function(name, type, body, callback, volatile: !!volatile) }
end

Instance Method Details

#add_function(name, type, body, callback = nil, volatile: false) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 45

def add_function(name, type, body, callback = nil, volatile: false)
  @function_registry.register(name, type, body, callback, volatile: volatile)
  self
end

#add_functions(functions) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 50

def add_functions(functions)
  functions.each { |(name, type, body, callback, volatile)| add_function(name, type, body, callback, volatile: !!volatile) }
  self
end

#aliases ⇒ Object

explicitly configured aliases win; otherwise the module-level default is resolved lazily so it can be set after this calculator was created



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# File 'lib/dentaku/calculator.rb', line 33

def aliases
  @aliases || Dentaku.aliases
end

#ast(expression) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 133

def ast(expression)
  return expression if expression.is_a?(AST::Node)
  return expression.map { |e| ast(e) } if expression.is_a? Array

  @ast_cache.fetch(expression) {
    options = {
      aliases: aliases,
      case_sensitive: case_sensitive,
      function_registry: @function_registry,
      raw_date_literals: raw_date_literals
    }

    tokens = tokenizer.tokenize(expression, options)
    Parser.new(tokens, options).parse.tap do |node|
      @ast_cache[expression] = node if cache_ast?
    end
  }
end

#cache_ast? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dentaku/calculator.rb', line 231

def cache_ast?
  return false if @disable_ast_cache

  @cache_ast.nil? ? Dentaku.cache_ast? : @cache_ast
end

#cache_dependency_order? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dentaku/calculator.rb', line 237

def cache_dependency_order?
  @cache_dependency_order.nil? ? Dentaku.cache_dependency_order? : @cache_dependency_order
end

#clear ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 223

def clear
  @memory = {}
end

#clear_cache(pattern = :all) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 156

def clear_cache(pattern = :all)
  case pattern
  when :all
    @ast_cache = {}
  when String
    @ast_cache.delete(pattern)
  when Regexp
    @ast_cache.delete_if { |k, _| k =~ pattern }
  else
    raise ::ArgumentError
  end
end

#dependencies(expression, context = {}) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 104

def dependencies(expression, context = {})
  # dup inside the block: `store` now restores in place, so the caller
  # needs its own copy of the merged context rather than the live memory
  test_context = context.nil? ? {} : store(context) { memory.dup }

  case expression
  when Dentaku::AST::Node
    expression.dependencies(test_context)
  when Array
    expression.flat_map { |e| dependencies(e, context) }
  else
    ast(expression).dependencies(test_context)
  end
end

#disable_cache ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 55

def disable_cache
  @disable_ast_cache = true
  yield(self) if block_given?
ensure
  @disable_ast_cache = false
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dentaku/calculator.rb', line 227

def empty?
  memory.empty?
end

#evaluate(expression, data = {}, &block) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 62

def evaluate(expression, data = {}, &block)
  context = evaluation_context(data, :permissive)
  return evaluate_array(expression, context, &block) if expression.is_a?(Array)

  evaluate!(expression, context)
rescue Dentaku::Error => ex
  block.call(expression, ex) if block_given?
end

#evaluate!(expression, data = {}, &block) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 75

def evaluate!(expression, data = {}, &block)
  context = evaluation_context(data, :strict)
  return evaluate_array!(expression, context, &block) if expression.is_a? Array

  store(context) do
    node = ast(expression)
    unbound = node.dependencies(memory)

    unless unbound.empty?
      raise UnboundVariableError.new(unbound),
            "no value provided for variables: #{unbound.uniq.join(', ')}"
    end

    node.value(memory)
  end
end

#evaluation_context(data, evaluation_mode) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 169

def evaluation_context(data, evaluation_mode)
  data.key?(:__evaluation_mode) ? data : data.merge(__evaluation_mode: evaluation_mode)
end

#identifiers(expression) ⇒ Object

every identifier the expression could reference, regardless of branching: purely syntactic, ignores stored memory, and never evaluates guards or functions



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# File 'lib/dentaku/calculator.rb', line 122

def identifiers(expression)
  case expression
  when Dentaku::AST::Node
    expression.dependencies(AST::Node::STATIC_CONTEXT).uniq
  when Array
    expression.flat_map { |e| identifiers(e) }.uniq
  else
    ast(expression).dependencies(AST::Node::STATIC_CONTEXT).uniq
  end
end

#load_cache(ast_cache) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 152

def load_cache(ast_cache)
  @ast_cache = ast_cache
end

#solve(expression_hash, &block) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 100

def solve(expression_hash, &block)
  BulkExpressionSolver.new(expression_hash, self).solve(&block)
end

#solve!(expression_hash) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 96

def solve!(expression_hash)
  BulkExpressionSolver.new(expression_hash, self).solve!
end

#store(key_or_hash, value = nil) ⇒ Object Also known as: bind 



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# File 'lib/dentaku/calculator.rb', line 173

def store(key_or_hash, value = nil)
  pairs = pairs_to_store(key_or_hash, value)

  unless block_given?
    pairs.each { |key, val| memory[key] = val }
    return self
  end

  # `evaluate!` routes every call through here, so snapshotting the whole
  # memory hash makes each evaluation scale with the number of stored
  # variables (#336). Undoing just the keys this call touched is O(pairs)
  # instead of O(memory) -- but it is only equivalent while nothing else
  # writes into memory during the block. The identifier cache does exactly
  # that, so when it is enabled we still need the wholesale snapshot to
  # keep cached values scoped to a single evaluation.
  if Dentaku.cache_identifier?
    restore = Hash[memory]
    pairs.each { |key, val| memory[key] = val }

    begin
      yield
    ensure
      @memory = restore
    end
  else
    undo = pairs.map { |key, _| [key, memory.key?(key), memory[key]] }
    pairs.each { |key, val| memory[key] = val }

    begin
      yield
    ensure
      undo.each { |key, present, val| present ? memory[key] = val : memory.delete(key) }
    end
  end
end

#store_formula(key, formula) ⇒ Object 



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# File 'lib/dentaku/calculator.rb', line 219

def store_formula(key, formula)
  store(key, ast(formula))
end