Class: Prattle::Evaluator

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

Defined Under Namespace

Classes: Scope

Instance Method Summary collapse

Constructor Details

#initialize(nodes, debug = false) ⇒ Evaluator

Returns a new instance of Evaluator



31
32
33
34
35
# File 'lib/prattle/evaluator.rb', line 31

def initialize(nodes, debug=false)
  @nodes = Array(nodes)
  @debug = debug
  @lobby = Lobby.new
end

Instance Method Details

#add_method(n) ⇒ Object



69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
# File 'lib/prattle/evaluator.rb', line 69

def add_method(n)
  name = n.initial.receiver.name
  sig = n.cascades[0]
  body = n.cascades[1].arguments[0]

  puts "Adding method #{sig.method_name} to #{name}"

  begin
    const = Object.const_get(name)
  rescue NameError
    const = Class.new
    Object.const_set name, const
  end

  const.dynamic_method sig.method_name.to_sym do |g|
    g.total_args = sig.arguments.size
    g.required_args = g.total_args
    g.local_count = g.required_args

    scope = Scope.new
    g.push_state(scope)

    sig.arguments.each do |arg|
      scope.add_variable arg.name
    end

    body.body.each_with_index do |node,idx|
      g.pop unless idx == 0
      node.bytecode(g)
    end

    g.ret
  end
end

#compileObject



118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
# File 'lib/prattle/evaluator.rb', line 118

def compile
  detect_methods
  cm = @lobby.metaclass.dynamic_method :call do |g|
    scope = Scope.new
    g.push_state(scope)

    if @nodes.empty?
      g.push :nil
    else
      @nodes.each_with_index do |node,idx|
        g.pop unless idx == 0
        node.bytecode(g)
      end
    end

    g.ret
  end

  puts cm.decode if @debug
end

#detect_methodsObject



104
105
106
107
108
109
110
111
112
113
114
115
116
# File 'lib/prattle/evaluator.rb', line 104

def detect_methods
  @nodes.delete_if do |n|
    if n.kind_of? AST::CascadeSend
      init = n.initial
      if init.kind_of? AST::UnarySend and init.method_name == "define"
        add_method(n)
        next true
      end
    end

    false
  end
end

#runObject



139
140
141
142
# File 'lib/prattle/evaluator.rb', line 139

def run
  compile
  @lobby.call
end