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Contents
require 'dentaku/evaluator'
require 'dentaku/token'
require 'dentaku/tokenizer'
module Dentaku
class Calculator
attr_reader :result
def initialize
clear
end
def evaluate(expression, data={})
@tokenizer ||= Tokenizer.new
@tokens = @tokenizer.tokenize(expression)
store(data) do
@evaluator ||= Evaluator.new
@result = @evaluator.evaluate(replace_identifiers_with_values)
end
end
def memory(key=nil)
key ? @memory[key.to_sym] : @memory
end
def store(key_or_hash, value=nil)
restore = @memory.dup
if value
@memory[key_or_hash.to_sym] = value
else
key_or_hash.each do |key, value|
@memory[key.to_sym] = value if value
end
end
if block_given?
result = yield
@memory = restore
return result
end
self
end
alias_method :bind, :store
def clear
@memory = {}
end
def empty?
@memory.empty?
end
private
def replace_identifiers_with_values
@tokens.map do |token|
if token.is?(:identifier)
value = memory(token.value)
type = type_for_value(value)
Token.new(type, value)
else
token
end
end
end
def type_for_value(value)
value.is_a?(String) ? :string : :numeric
end
end
end
Version data entries
11 entries across 11 versions & 1 rubygems