Class: RuleSet

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

Overview

Sets of rules (Can also contain conditional or fallback sets of rulesets)

Instance Method Summary collapse

Constructor Details

#initialize(grammar, raw) ⇒ RuleSet

Returns a new instance of RuleSet.



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# File 'lib/tracery.rb', line 404

def initialize(grammar, raw)
    @raw = raw
    @grammar = grammar
    @falloff = 1
    @random = Random.new
    
    @defaultUses = {}
    
    if(raw.is_a? Array) then
        @defaultRules = raw
    else
        if(raw.is_a? String) then
            @defaultRules = [raw];
        else
            # TODO: support for conditional and hierarchical rule sets
        end
    end
end

Instance Method Details

#clearState ⇒ Object 



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# File 'lib/tracery.rb', line 458

def clearState
    @defaultUses = {}
    #TODO_ should clear shuffled deck too?
end

#selectRule ⇒ Object 



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# File 'lib/tracery.rb', line 423

def selectRule
    # puts "Get rule #{@raw}"
    
    #TODO_ : RuleSet.getRule @ conditionalRule
    #TODO_ : RuleSet.getRule @ ranking
    
    if(!@defaultRules.nil?) then
        index = 0
        # Select from this basic array of rules
        # Get the distribution from the grammar if there is no other
        distribution = @distribution || @grammar.distribution
        case(distribution)
            when "shuffle" then
                #create a shuffled deck
                if(@shuffledDeck.nil? || @shuffledDeck.empty?)
                    #TODO_ - use fyshuffle and falloff
                    @shuffledDeck = (0...@defaultRules.size).to_a.shuffle
                end
                index = @shuffledDeck.pop
            when "weighted" then
                @errors << "Weighted distribution not yet implemented"
            when "falloff" then
                @errors << "Falloff distribution not yet implemented"
            else
                index = ((@random.rand ** @falloff) * @defaultRules.size).floor
        end
    
        @defaultUses[index] = (@defaultUses[index] || 0) + 1
        return @defaultRules[index]
    end

    @errors << "No default rules defined for #{self}"
    return nil
end