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Ruby/YAML Smart Answers

README for Ruby and YAML-based smart answer flows

Smart answer flows are stored in lib/smart_answer_flows/*.rb. Corresponding text is in lib/smart_answer_flows/locales/*.yml. The code responsible for executing the flow of those questions is in the lib folder of this project.

Smart answer syntax

Question types

  • multiple_choice - choose a single value from a list of values. Response is a string.
  • checkbox_question - choose multiple values from a list of values. Response is a list.
  • country_select - choose a single country.
  • date_question - choose a single date
  • value_question - enter a single string value (free text)
  • money_question - enter a money amount. The response is converted to a Money object.
  • salary_question - enter a salary as either a weekly or monthly money amount. Coverted to a Salary object.

Defining next node rules

There are two syntaxes for defining next node rules. The older syntax uses a block which returns a symbol indicating the next node. This syntax is deprecated.

next_node do |response|
  response == 'green' ? :green : :red
end

The disadvantage of this syntax is that it's not possible to analyze the flow to find out the possible paths through the flow. A newer syntax has been created which allows the flow to be analyzed and a visualisation to be produced.

Here is the same logic expressed using the new syntax:

next_node_if(:green, responded_with('green')) )
next_node(:red)

The responded_with function actually returns a predicate which will be invoked during processing. If the predicate returns true then the :green node will be next, otherwise the next rule will be evaluated. In this case the next rule says :red is the next node with no condition.

Predicate helpers

  • responded_with(value) - value can be either a string or an array of values
  • variable_matches(varname, value) - varname is a symbol representing the name of the variable to test, value can be either a single value or an array
  • response_has_all_of(required_responses) - only for checkbox questions, true if all of the required responses were checked. required_responses can be a single value or an array.
  • response_is_one_of(responses) - only for checkbox questions, true if ANY of the responses were checked. responses can be a single value or an array.

Combining predicates

Predicates can be combined using logical conjunctions | or &:

next_node_if(:orange, variable_matches(:first_colour, "red") & variable_matches(:second_colour, "yellow"))
next_node_if(:monochrome, variable_matches(:first_colour, "black") | variable_matches(:second_colour, "white"))

Structuring rules by nesting

Predicates can also be organised by nesting using on_condition, e.g.

on_condition(responded_with("red")) do
  next_node_if(:orange, variable_matches(:first_color, "yellow"))
  next_node(:red)
end
next_node(:blue)

Here's a truth table for the above scenario:

| | Yellow | other | Red | orange | red | other | blue | blue

Defining named predicates

Named predicates can also be defined using

define_predicate(:can_has_cheesburger?) do |response|
  # logic here…
end

next_node_if(:something, can_has_cheesburger?)