do-end vs {}

gistfile1.txt

2.0.0p0 :036 > puts s1
10.times do |n|
puts n
end
 => nil

2.0.0p0 :037 > puts s2
10.times { |n|
puts n
}
 => nil

2.0.0p0 :038 > puts d1 = RubyVM::InstructionSequence.compile(s1).disasm
== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
== catch table
| catch type: break  st: 0002 ed: 0006 sp: 0000 cont: 0006
|------------------------------------------------------------------------
0000 trace            1                                               (   1)
0002 putobject        10
0004 send             <callinfo!mid:times, argc:0, block:block in <compiled>>
0006 leave
== disasm: <RubyVM::InstructionSequence:block in <compiled>@<compiled>>=
== catch table
| catch type: redo   st: 0000 ed: 0011 sp: 0000 cont: 0000
| catch type: next   st: 0000 ed: 0011 sp: 0000 cont: 0011
|------------------------------------------------------------------------
local table (size: 2, argc: 1 [opts: 0, rest: -1, post: 0, block: -1] s3)
[ 2] n<Arg>
0000 trace            256                                             (   1)
0002 trace            1                                               (   2)
0004 putself
0005 getlocal_OP__WC__0 2
0007 opt_send_simple  <callinfo!mid:puts, argc:1, FCALL|ARGS_SKIP>
0009 trace            512                                             (   3)
0011 leave                                                            (   2)
 => nil

2.0.0p0 :039 > puts d2 = RubyVM::InstructionSequence.compile(s2).disasm
== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
== catch table
| catch type: break  st: 0002 ed: 0006 sp: 0000 cont: 0006
|------------------------------------------------------------------------
0000 trace            1                                               (   1)
0002 putobject        10
0004 send             <callinfo!mid:times, argc:0, block:block in <compiled>>
0006 leave
== disasm: <RubyVM::InstructionSequence:block in <compiled>@<compiled>>=
== catch table
| catch type: redo   st: 0000 ed: 0011 sp: 0000 cont: 0000
| catch type: next   st: 0000 ed: 0011 sp: 0000 cont: 0011
|------------------------------------------------------------------------
local table (size: 2, argc: 1 [opts: 0, rest: -1, post: 0, block: -1] s3)
[ 2] n<Arg>
0000 trace            256                                             (   1)
0002 trace            1                                               (   2)
0004 putself
0005 getlocal_OP__WC__0 2
0007 opt_send_simple  <callinfo!mid:puts, argc:1, FCALL|ARGS_SKIP>
0009 trace            512                                             (   3)
0011 leave                                                            (   2)
 => nil

2.0.0p0 :040 > d1 == d2
 => true
 
2.0.0p0 :044 > l1 = Ripper.lex(s1)
 => [[[1, 0], :on_int, "10"], [[1, 2], :on_period, "."], [[1, 3], :on_ident, "times"], [[1, 8], :on_sp, " "], [[1, 9], :on_kw, "do"], [[1, 11], :on_sp, " "], [[1, 12], :on_op, "|"], [[1, 13], :on_ident, "n"], [[1, 14], :on_op, "|"], [[1, 15], :on_ignored_nl, "\n"], [[2, 0], :on_ident, "puts"], [[2, 4], :on_sp, " "], [[2, 5], :on_ident, "n"], [[2, 6], :on_nl, "\n"], [[3, 0], :on_kw, "end"]]
 
2.0.0p0 :045 > l2 = Ripper.lex(s2)
 => [[[1, 0], :on_int, "10"], [[1, 2], :on_period, "."], [[1, 3], :on_ident, "times"], [[1, 8], :on_sp, " "], [[1, 9], :on_lbrace, "{"], [[1, 10], :on_sp, " "], [[1, 11], :on_op, "|"], [[1, 12], :on_ident, "n"], [[1, 13], :on_op, "|"], [[1, 14], :on_ignored_nl, "\n"], [[2, 0], :on_ident, "puts"], [[2, 4], :on_sp, " "], [[2, 5], :on_ident, "n"], [[2, 6], :on_nl, "\n"], [[3, 0], :on_rbrace, "}"]]

2.0.0p0 :046 > l1 == l2
 => false