Module: Dogfood::DSL::Compiler

Defined in:
lib/dogfood/dsl/compiler.rb

Overview

Compiles a validated scenario YAML hash into an anonymous Class(Dogfood::StoryBase). See SPEC.md 4.9 and 4.7.

Constant Summary collapse

TERMINAL_STATUSES = 
%i[paid declined voided].freeze
BUILTIN_NAMES = 
%i[update_state manual_step wait_for note set_binding].freeze

Class Method Summary collapse

Class Method Details

.collect_block_names(steps) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 249

def self.collect_block_names(steps)
  steps.flat_map do |step|
    if step[:type] == :maybe
      collect_block_names(step[:then]) + collect_block_names(step[:else])
    else
      [step[:name]]
    end
  end
end

.collect_call_names(ast) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 233

def self.collect_call_names(ast)
  ast[:stages].flat_map { |s| collect_stage_names(s[:steps]) }
end

.collect_stage_names(steps) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 237

def self.collect_stage_names(steps)
  steps.flat_map do |step|
    case step[:type]
    when :call then [step[:name]]
    when :when
      collect_block_names(step[:then]) + collect_block_names(step[:else])
    when :maybe then collect_block_names(step[:then]) + collect_block_names(step[:else])
    else []
    end
  end
end

.compile(yaml, pack:) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 10

def self.compile(yaml, pack:)
  ast = parse_ast(yaml)
  validate_calls(ast, pack)

  klass = Class.new(Dogfood::StoryBase) do
    include Dogfood::Steps::Builtins
    pack.step_modules.each { |m| include(m) }
    pack.mixin_modules.each { |m| include(m) }
    define_singleton_method(:compiled_ast) { ast }
    define_singleton_method(:compiled_pools) { pack.pools }
    define_singleton_method(:compiled_faker) { Dogfood::FakerProxy.new }
  end

  klass.define_method(:title) { yaml["title"] }

  klass.define_method(:advance) do |day_index:|
    @current_day = day_index
    @bindings ||= {}
    @branch_for ||= {}
    @next_stage ||= nil

    stages.each do |stage_spec|
      next unless @next_stage.nil? || @next_stage == stage_spec[:stage]
      run_stage(stage_spec)
      @next_stage = next_stage_after(stage_spec[:stage])
    end

    terminal = TERMINAL_STATUSES.include?(@state[:status])
    {
      id: id,
      steps: @steps,
      state: @state,
      terminal: terminal,
      resume_on: terminal ? nil : next_resume_day
    }
  end

  klass.define_method(:stages) { self.class.compiled_ast[:stages] }

  klass.define_method(:next_stage_after) do |stage|
    idx = self.class.compiled_ast[:stages].index { |s| s[:stage] == stage }
    nxt = self.class.compiled_ast[:stages][idx + 1]
    nxt && nxt[:stage]
  end

  klass.define_method(:run_stage) do |stage_spec|
    branch = resolve_branch(stage_spec)
    stage_spec[:steps].each do |step_spec|
      run_step(step_spec, branch)
    end
  end

  klass.define_method(:resolve_branch) do |stage_spec|
    weights = stage_spec[:branch_weights]
    return nil unless weights
    @branch_for[stage_spec[:stage]] ||= @rng.branch(weights)
  end

  klass.define_method(:run_step) do |step_spec, branch|
    case step_spec[:type]
    when :call
      return if step_spec[:when_branch] && step_spec[:when_branch] != branch
      call_step(step_spec)
    when :when
      list = eval_expr(step_spec[:expr]) ? step_spec[:then] : step_spec[:else]
      (list || []).each { |c| run_step(c, nil) }
    when :maybe
      if @rng.rand < step_spec[:prob]
        step_spec[:then].each { |c| run_step(c, nil) }
      else
        step_spec[:else].each { |c| run_step(c, nil) }
      end
    end
  end

  klass.define_method(:call_step) do |call_spec|
    args = eval_with(call_spec[:with])
    ret = send(call_spec[:name], **args)
    bind_out(call_spec[:out], ret)
  end

  klass.define_method(:eval_with) do |with_hash|
    (with_hash || {}).each_with_object({}) do |(k, v), acc|
      acc[k.to_sym] = Dogfood::DSL::Evaluator.eval(v, bindings: @bindings, state: @state, rng: @rng,
        self_object: self, pools: self.class.compiled_pools, faker: self.class.compiled_faker)
    end
  end

  klass.define_method(:eval_expr) do |expr|
    Dogfood::DSL::Evaluator.eval(expr, bindings: @bindings, state: @state, rng: @rng,
      self_object: self, pools: self.class.compiled_pools, faker: self.class.compiled_faker)
  end

  klass.define_method(:bind_out) do |out, ret|
    return unless out
    if out.is_a?(Array)
      if ret.is_a?(Hash)
        out.each { |name| @bindings[name.to_sym] = ret[name.to_sym] }
      else
        out.each_with_index { |name, i| @bindings[name.to_sym] = ret[i] }
      end
    else
      @bindings[out.to_sym] = ret
    end
  end

  klass.define_method(:next_resume_day) do
    resume = self.class.compiled_ast[:resume]
    resume && resume[:after_await] == :same_day ? @current_day : @current_day + 1
  end

  klass
end

.normalize_out(out) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 213

def self.normalize_out(out)
  case out
  when Array then out.map(&:to_sym)
  when String then out.to_sym
  else nil
  end
end

.parse_ast(yaml) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 124

def self.parse_ast(yaml)
  stages = yaml["stages"].map(&:to_sym)
  branches = (yaml["branches"] || {}).each_with_object({}) do |(stage, weights), acc|
    acc[stage.to_sym] = weights.each_with_object({}) { |(k, v), h| h[k.to_sym] = v }
  end

  stage_list = stages.map do |stage|
    steps = yaml["stages_def"][stage.to_s].map { |s| parse_step(s, stage.to_s) }
    {
      stage: stage,
      branch_weights: branches[stage],
      steps: steps
    }
  end

  resume = if yaml["resume"] && yaml["resume"]["after_await"]
             { after_await: yaml["resume"]["after_await"].to_sym }
           end

  {
    name: yaml["name"].to_sym,
    title: yaml["title"],
    stages: stage_list,
    delays: (yaml["delays"] || {}).keys.map(&:to_sym),
    resume: resume
  }
end

.parse_block_step(step, stage) ⇒ Object

A step inside a when/then/else block may be a call or a maybe probability step, but never another when. This is the depth-1 limit (SPEC.md 4.7).



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# File 'lib/dogfood/dsl/compiler.rb', line 197

def self.parse_block_step(step, stage)
  if step.key?("when")
    raise Dogfood::NestingTooDeep, "nesting too deep at stage #{stage}: when blocks may not nest"
  end
  if step.key?("maybe")
    {
      type: :maybe,
      prob: step["maybe"],
      then: step["then"].map { |c| parse_call(c, stage) },
      else: step["else"] ? step["else"].map { |c| parse_call(c, stage) } : []
    }
  else
    parse_call(step, stage)
  end
end

.parse_call(step, stage) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 181

def self.parse_call(step, stage)
  unless step.key?("call")
    raise Dogfood::NestingTooDeep, "nesting too deep at stage #{stage}: only call steps allowed in blocks"
  end
  {
    type: :call,
    name: step["call"].to_sym,
    when_branch: nil,
    with: step["with"] || {},
    out: normalize_out(step["out"])
  }
end

.parse_step(step, stage) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 152

def self.parse_step(step, stage)
  if step.key?("call")
    out = step["out"]
    {
      type: :call,
      name: step["call"].to_sym,
      when_branch: step["when_branch"]&.to_sym,
      with: step["with"] || {},
      out: normalize_out(out)
    }
  elsif step.key?("when")
    {
      type: :when,
      expr: step["when"],
      then: step["then"].map { |c| parse_block_step(c, stage) },
      else: step["else"] ? step["else"].map { |c| parse_block_step(c, stage) } : []
    }
  elsif step.key?("maybe")
    {
      type: :maybe,
      prob: step["maybe"],
      then: step["then"].map { |c| parse_call(c, stage) },
      else: step["else"] ? step["else"].map { |c| parse_call(c, stage) } : []
    }
  else
    raise Dogfood::NestingTooDeep, "invalid step in stage #{stage}"
  end
end

.validate_calls(ast, pack) ⇒ Object 



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# File 'lib/dogfood/dsl/compiler.rb', line 223

def self.validate_calls(ast, pack)
  names = collect_call_names(ast).uniq
  names.each do |name|
    next if BUILTIN_NAMES.include?(name)
    found = pack.step_modules.any? { |m| m.instance_methods.include?(name) } ||
            pack.mixin_modules.any? { |m| m.instance_methods.include?(name) }
    raise Dogfood::Pack::UnknownScenario, "call :#{name} does not resolve to a pack step module" unless found
  end
end