Module: Rubasteme::AST::Misc

Included in:
Rbsiev::Evaluator
Defined in:
lib/rubasteme/ast/misc.rb

Overview

Miscellaneous functions to operate AST nodes.

Instance Method Summary collapse

Instance Method Details

#bindings_specs(ast_node) ⇒ Object 



75
76
77
78
 
# File 'lib/rubasteme/ast/misc.rb', line 75

def bindings_specs(ast_node)
  check_type(:ast_bindings, ast_node)
  ast_node.elements
end

#cond_to_if(ast_node) ⇒ Object

Converter function.



82
83
84
85
 
# File 'lib/rubasteme/ast/misc.rb', line 82

def cond_to_if(ast_node)
  check_type(:ast_cond, ast_node)
  expand_clauses(ast_node.cond_clauses)
end

#do_to_named_let(ast_node, loop_identifier) ⇒ Object 



126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
 
# File 'lib/rubasteme/ast/misc.rb', line 126

def do_to_named_let(ast_node, loop_identifier)
  bind_specs = []
  bind_specs_with_step = []
  ast_node.iteration_bindings.each { |iter_spec|
    spec = make_bind_spec(iter_spec.identifier, iter_spec.init)
    if iter_spec.step
      bind_specs_with_step << [spec, iter_spec.step]
    else
      bind_specs << spec
    end
  }

  let_bindings = make_bindings(bind_specs_with_step.map{|e| e[0]})

  test_and_do_result = ast_node.test_and_do_result

  if_predicate = test_and_do_result.test
  if_consequent = make_begin(rest_nodes(test_and_do_result))

  sequence = []
  sequence += ast_node.commands
  sequence << make_combination(make_identifier(loop_identifier),
                               bind_specs_with_step.map{|e| e[1]})
  if_alternative = make_begin(sequence)

  if_node = make_if(if_predicate, if_consequent, if_alternative)
  let_body = make_body(nil, make_sequence([if_node]))
  let_node = make_let(let_bindings, let_body)
  let_node.identifier = make_identifier(loop_identifier)

  if bind_specs.empty?
    let_node
  else
    let_body = make_body(nil, make_sequence([let_node]))
    make_let(make_bindings(bind_specs), let_body)
  end
end

#empty_node?(obj) ⇒ Boolean

For AST::ListNode. They also accept an Array object as their arugment.

Returns:

  • (Boolean) 


23
24
25
26
 
# File 'lib/rubasteme/ast/misc.rb', line 23

def empty_node?(obj)
  check_list_type(obj)
  obj.empty?
end

#first_binding(ast_node) ⇒ Object 



67
68
69
 
# File 'lib/rubasteme/ast/misc.rb', line 67

def first_binding(ast_node)
  first_node(ast_node)
end

#first_node(obj) ⇒ Object 



33
34
35
36
 
# File 'lib/rubasteme/ast/misc.rb', line 33

def first_node(obj)
  check_list_type(obj)
  obj[0]
end

#identifier(ast_node) ⇒ Object

For AST::IdentifierNode.



12
13
14
15
16
17
18
 
# File 'lib/rubasteme/ast/misc.rb', line 12

def identifier(ast_node)
  if ast_node.respond_to?(:literal)
    ast_node.literal
  else
    raise Error, "wrong type node: got=%s" % ast_node.to_a.to_s
  end
end

#last_binding?(ast_node) ⇒ Boolean

For AST::BindingsNode

Returns:

  • (Boolean) 


63
64
65
 
# File 'lib/rubasteme/ast/misc.rb', line 63

def last_binding?(ast_node)
  last_node?(list_elements(ast_node))
end

#last_node?(obj) ⇒ Boolean

Returns:

  • (Boolean) 


28
29
30
31
 
# File 'lib/rubasteme/ast/misc.rb', line 28

def last_node?(obj)
  check_list_type(obj)
  obj.size == 1
end

#let_star_to_nested_lets(bindings, body) ⇒ Object 



115
116
117
118
119
120
121
122
123
124
 
# File 'lib/rubasteme/ast/misc.rb', line 115

def let_star_to_nested_lets(bindings, body)
  single_bindings = make_bindings([first_binding(bindings)])
  if last_binding?(bindings)
    make_let(single_bindings, body)
  else
    seq = make_sequence([let_star_to_nested_lets(rest_bindings(bindings), body)])
    new_body = make_body(nil, seq)
    make_let(single_bindings, new_body)
  end
end

#let_to_combination(ast_node) ⇒ Object 



98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
 
# File 'lib/rubasteme/ast/misc.rb', line 98

def let_to_combination(ast_node)
  check_types([:ast_let, :ast_letrec, :ast_letrec_star], ast_node)

  identifiers = []
  operands = []

  ast_node.bindings.each { |bind_spec|
    identifiers << bind_spec.identifier
    operands << bind_spec.expression
  }

  formals = make_formals(identifiers)
  operator = make_lambda(formals, ast_node.body)

  make_combination(operator, operands)
end

#list_elements(obj) ⇒ Object 



43
44
45
46
47
48
49
50
51
52
 
# File 'lib/rubasteme/ast/misc.rb', line 43

def list_elements(obj)
  case obj
  when ListNode
    obj.elements
  when Array
    obj
  else
    raise Error, "wrong type node: expected=(Array or ListNode), got=%s" % obj.to_a.to_s
  end
end

#make_begin(nodes) ⇒ Object 



178
179
180
181
182
183
184
185
186
187
188
189
 
# File 'lib/rubasteme/ast/misc.rb', line 178

def make_begin(nodes)
  begin_node = Rubasteme::AST.instantiate(:ast_begin, nil)
  case nodes
  when Rubasteme::AST::SequenceNode
    begin_node.sequence = nodes
  when Array
    begin_node.sequence = make_sequence(nodes)
  else
    raise Error, "wrong type argument: expected= Array or Rubasteme::AST::SequenceNode, got=%s" % nodes.class
  end
  begin_node
end

#make_bind_spec(identifier, expression) ⇒ Object 



249
250
251
252
253
254
 
# File 'lib/rubasteme/ast/misc.rb', line 249

def make_bind_spec(identifier, expression)
  spec_node = Rubasteme::AST.instantiate(:ast_bind_spec, nil)
  spec_node.identifier = identifier
  spec_node.expression = expression
  spec_node
end

#make_bindings(bind_spec_nodes) ⇒ Object 



256
257
258
259
260
261
262
263
 
# File 'lib/rubasteme/ast/misc.rb', line 256

def make_bindings(bind_spec_nodes)
  bindings_node = Rubasteme::AST.instantiate(:ast_bindings, nil)
  bind_spec_nodes.each { |spec|
    check_type(:ast_bind_spec, spec)
    bindings_node.add_bind_spec(spec)
  }
  bindings_node
end

#make_body(definitions, sequence) ⇒ Object 



191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
 
# File 'lib/rubasteme/ast/misc.rb', line 191

def make_body(definitions, sequence)
  body_node = Rubasteme::AST.instantiate(:ast_body, nil)

  if definitions.nil?
    definitions = Rubasteme::AST.instantiate(:ast_internal_definitions, nil)
  end
  if sequence.nil?
    sequence = Rubasteme::ASt.instantiate(:ast_sequence, nil)
  end

  body_node.definitions = definitions
  body_node.sequence = sequence

  body_node
end

#make_combination(operator, operands) ⇒ Object 



231
232
233
234
235
236
237
238
 
# File 'lib/rubasteme/ast/misc.rb', line 231

def make_combination(operator, operands)
  proc_call_node = Rubasteme::AST.instantiate(:ast_procedure_call, nil)
  proc_call_node.operator = operator
  operands.each { |node|
    proc_call_node.add_operand(node)
  }
  proc_call_node
end

#make_formals(identifiers) ⇒ Object 



222
223
224
225
226
227
228
229
 
# File 'lib/rubasteme/ast/misc.rb', line 222

def make_formals(identifiers)
  formals_node = Rubasteme::AST.instantiate(:ast_formals, nil)
  identifiers.each { |identifier_node|
    check_type(:ast_identifier, identifier_node)
    formals_node.add_identifier(identifier_node)
  }
  formals_node
end

#make_identifier(literal) ⇒ Object

Construcing functions.



166
167
168
 
# File 'lib/rubasteme/ast/misc.rb', line 166

def make_identifier(literal)
  Rubasteme::AST::instantiate(:ast_identifier, literal)
end

#make_if(predicate, consequent, alternative) ⇒ Object 



214
215
216
217
218
219
220
 
# File 'lib/rubasteme/ast/misc.rb', line 214

def make_if(predicate, consequent, alternative)
  if_node = Rubasteme::AST.instantiate(:ast_conditional, nil)
  if_node.test = predicate
  if_node.consequent = consequent
  if_node.alternate = alternative if alternative
  if_node
end

#make_lambda(formals, body) ⇒ Object 



170
171
172
173
174
175
176
 
# File 'lib/rubasteme/ast/misc.rb', line 170

def make_lambda(formals, body)
  check_type(:ast_body, body)
  lambda_node = Rubasteme::AST.instantiate(:ast_lambda_expression, nil)
  lambda_node.formals = formals
  lambda_node.body = body
  lambda_node
end

#make_let(bindings, body) ⇒ Object 



240
241
242
243
244
245
246
247
 
# File 'lib/rubasteme/ast/misc.rb', line 240

def make_let(bindings, body)
  check_type(:ast_bindings, bindings)
  check_type(:ast_body, body)
  let_node = Rubasteme::AST.instantiate(:ast_let, nil)
  let_node.bindings = bindings
  let_node.body = body
  let_node
end

#make_sequence(nodes) ⇒ Object 



207
208
209
210
211
212
 
# File 'lib/rubasteme/ast/misc.rb', line 207

def make_sequence(nodes)
  check_list_type(nodes)
  seq_node = Rubasteme::AST.instantiate(:ast_sequence, nil)
  nodes.each{|exp| seq_node.add_expression(exp)}
  seq_node
end

#parameters(ast_node) ⇒ Object

for AST::FormalsNode



56
57
58
59
 
# File 'lib/rubasteme/ast/misc.rb', line 56

def parameters(ast_node)
  check_type(:ast_formals, ast_node)
  ast_node.map{|e| identifier(e)}
end

#rest_bindings(ast_node) ⇒ Object 



71
72
73
 
# File 'lib/rubasteme/ast/misc.rb', line 71

def rest_bindings(ast_node)
  make_bindings(rest_nodes(ast_node))
end

#rest_nodes(obj) ⇒ Object 



38
39
40
41
 
# File 'lib/rubasteme/ast/misc.rb', line 38

def rest_nodes(obj)
  check_list_type(obj)
  obj[1..-1]
end

#sequence_to_node(ast_node) ⇒ Object 



87
88
89
90
91
92
93
94
95
96
 
# File 'lib/rubasteme/ast/misc.rb', line 87

def sequence_to_node(ast_node)
  check_type(:ast_sequence, ast_node)
  if ast_node.empty?
    EMPTY_LIST
  elsif last_node?(ast_node)
    first_node(ast_node)
  else
    make_begin(ast_node)
  end
end