Class: QED::Advice

Inherits:
Object show all
Defined in:
lib/qed/advice.rb

Overview

Advice

This class tracks advice defined by demonstrandum and applique. Advice are evaluated in Scope, so that they will have access to the same local binding as the scripts themselves.

There are two types of advice: *pattern matchers* and *event signals*.

Pattern Matchers (When)

Matchers are evaluated when they match a description.

Event Signals (Before, After)

Event advice are triggered on symbolic targets which represent an event in the evaluation process, such as before an example is run, or after a demo finishes.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Advice

Returns a new instance of Advice.



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# File 'lib/qed/advice.rb', line 35

def initialize
  @matchers = []
  @signals  = [{}]
end

Instance Attribute Details

#matchers ⇒ Object (readonly)

Returns the value of attribute matchers.



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# File 'lib/qed/advice.rb', line 29

def matchers
  @matchers
end

#signals ⇒ Object (readonly)

Returns the value of attribute signals.



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# File 'lib/qed/advice.rb', line 32

def signals
  @signals
end

Instance Method Details

#add_event(type, &procedure) ⇒ Object 



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# File 'lib/qed/advice.rb', line 57

def add_event(type, &procedure)
  @signals.last[type.to_sym] = procedure
end

#add_match(patterns, &procedure) ⇒ Object 



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# File 'lib/qed/advice.rb', line 62

def add_match(patterns, &procedure)
  @matchers << [patterns, procedure]
end

#call(scope, type, *args) ⇒ Object 



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# File 'lib/qed/advice.rb', line 47

def call(scope, type, *args)
  case type
  when :when
    call_matchers(scope, *args)
  else
    call_signals(scope, type, *args)
  end
end

#call_matchers(scope, section) ⇒ Object 



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# File 'lib/qed/advice.rb', line 76

def call_matchers(scope, section)
  match = section.text
  args  = section.arguments
  matchers.each do |(patterns, proc)|
    compare = match
    matched = true
    params  = []
    patterns.each do |pattern|
      case pattern
      when Regexp
        regex = pattern
      else
        regex = match_string_to_regexp(pattern)
      end
      if md = regex.match(compare)
        params.concat(md[1..-1])
        compare = md.post_match
      else
        matched = false
        break
      end
    end
    if matched
      params += args
      #proc.call(*params)
      scope.instance_exec(*params, &proc)
    end
  end
end

#call_signals(scope, type, *args) ⇒ Object

React to an event.



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# File 'lib/qed/advice.rb', line 67

def call_signals(scope, type, *args)
  @signals.each do |set|
    proc = set[type.to_sym]
    #proc.call(*args) if proc
    scope.instance_exec(*args, &proc) if proc
  end
end

#signals_clear(type = nil) ⇒ Object

Clear advice.



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# File 'lib/qed/advice.rb', line 117

def signals_clear(type=nil)
  if type
    @signals.each{ |set| set.delete(type.to_sym) }
  else
    @signals = [{}]
  end
end

#signals_reset ⇒ Object

Clear last set of advice.



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# File 'lib/qed/advice.rb', line 107

def signals_reset
  @signals.pop
end

#signals_setup ⇒ Object 



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# File 'lib/qed/advice.rb', line 112

def signals_setup
  @signals.push({})
end