1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
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
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
=begin
Comprehensive test of break, next, redo and return statements semantics.
Doesn't test all interactions with exception handling though.
=end
def make_block name
%{
puts '#{name}.begin'
begin
if $statement == :next then
puts $statement
$state = true
next "#{name}"
elsif $statement == :break then
puts $statement
$state = true
break "#{name}"
elsif $statement == :return then
puts $statement
$state = true
return "#{name}"
else
if not $state then
puts $statement
$state = true
redo
end
end
rescue
# why the $! is nil here?
puts "#{name}.ERROR: #{$!.inspect}" +
($statement == :return ? " (unexpected return)" : " unreachable")
end
}
end
def run
puts 'run.begin'
test :break
test :next
test :redo
test :return
puts 'run.end'
end
def test statement
$statement = statement
puts 'test.begin'
f :call, :lambda, :owner => :active
f :yield, :lambda, :owner => :active
f :call, :lambda, :owner => :inactive
f :yield, :lambda, :owner => :inactive
f :call, :proc, :owner => :active, :converter => :active
f :yield, :proc, :owner => :active, :converter => :active
f :call, :proc, :owner => :inactive, :converter => :active
f :yield, :proc, :owner => :inactive, :converter => :active
f :call, :proc, :owner => :active, :converter => :inactive
f :yield, :proc, :owner => :active, :converter => :inactive
f :call, :proc, :owner => :inactive, :converter => :inactive
f :yield, :proc, :owner => :inactive, :converter => :inactive
puts '-'*55
puts 'test.end'
ensure
puts 'test.finally'
end
def f action, kind, frames
$action = action
$kind = kind
$owner = frames[:owner]
$converter = ($kind == :proc) ? frames[:converter] : :inactive
puts '-'*55, "#{$statement}: #{$action} #{$kind}, owner:#{$owner}, converter:#{$converter}", '-'*55
puts 'f.begin'
r = f0
puts "result = '#{r}'"
puts 'f.end' + state_msg
ensure
puts 'f.finally'
end
def define_procs
if $kind == :lambda then
$proc = lambda do |*a| # owner inactive
puts "args = #{a.inspect}"
a = a + [1]
eval make_block('lambda')
end
else
$proc = Proc.new do |*a| # owner inactive
puts "args = #{a.inspect}"
a = a + [1]
eval make_block('proc')
end
end
end
def f0
print 'f0.begin'
if $owner == :active then
if $converter == :inactive then
puts " <-- owner"
if $kind == :lambda then
$proc = lambda do |*a| # converter (Kernel#lambda) inactive
puts "args = #{a.inspect}"
a = a + [1]
eval make_block('lambda1')
end
else
$proc = Proc.new do |*a| # converter (Proc#new) inactive
puts "args = #{a.inspect}"
a = a + [1]
eval make_block('proc1')
end
end
else
$proc = nil # to be created later
end
else
puts
define_procs
end
f1
puts 'f0.end' + state_msg
ensure
puts 'f0.finally'
end
def f1
puts 'f1.begin'
f2
puts 'f1.end' + state_msg
ensure
puts 'f1.finally'
end
def f2
puts 'f2.begin'
r = f3 &$proc
puts "result = '#{r}'"
puts 'f2.end' + state_msg
ensure
puts 'f2.finally'
end
def f3 &p
$state = false
print 'f3.begin'
if p == nil then
puts ' <-- owner'
if $kind == :proc then
r = f4 true do |*a| # f4 is the converter
puts "args = #{a.inspect}"
a = a + [1]
eval make_block('proc2') # redo goes here (at the beginning of the block)
end # break unwinds to here
else
r = f4(false, &lambda do |*a| # lambda is the converter => it is inactive!
puts "args = #{a.inspect}"
a = a + [1]
eval make_block('lambda2') # redo goes here (at the beginning of the block)
end) # break does NOT uwind here
end
else
puts
r = f4 false, &p
end
puts "result = '#{r}'"
puts 'f3.end' + state_msg
ensure
puts 'f3.finally'
end
def f4 is_converter, &p
puts "f4.begin#{is_converter ? ' <-- converter' : ''}"
b = true
while b do # loop does NOT interfere with stack unwinding
f5 &p
b = false
end
puts 'f4.end' + state_msg
ensure
puts 'f4.finally'
end
def f5 &p
puts 'f5.begin'
invoke &p
puts 'f5.end' + state_msg
ensure
puts 'f5.finally'
end
def invoke &p
puts 'invoke.begin'
if $action == :yield then
puts 'yielding'
puts "yield-result = '#{yield}'" # next returns here
else
puts 'calling'
puts "call-result = '#{p[]}'" # next returns here
end
puts 'invoke.end' + state_msg
rescue
$state = false
puts "invoke.ERROR: #{$!.inspect}"
ensure
puts 'invoke.finally'
end
def state_msg
if $state then
$state = false
" <---- #{$statement} returned here"
else
""
end
end
run
|
