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32 lines
1.1 KiB
Markdown
32 lines
1.1 KiB
Markdown
# Disassemble Some Codes
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The
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[`RubyVM::InstructionSequence`](http://ruby-doc.org/core-2.2.0/RubyVM/InstructionSequence.html)
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class makes it easy to compile, disassemble, and inspect bits of Ruby code.
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We can quickly take a peek under the hood at a simple ruby statement, such
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as `a = 1 + 2`, like so:
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```ruby
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> ruby_code = 'a = 1 + 2'
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=> a = 1 + 2
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> compiled_code = RubyVM::InstructionSequence.compile(ruby_code)
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=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
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> puts compiled_code.disasm
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== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
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local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw:
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-1@-1, kwrest: -1])
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[ 2] a
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0000 trace 1 ( 1)
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0002 putobject_OP_INT2FIX_O_1_C_
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0003 putobject 2
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0005 opt_plus <callinfo!mid:+, argc:1, ARGS_SIMPLE>
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0007 dup
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0008 setlocal_OP__WC__0 2
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0010 leave
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=> nil
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```
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It is a bit archaic, but when we get to the line starting with `0002`, we
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see values (`1` and then `2`) pushed onto the stack, then operated on, and
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finally set on the local variable `a`. Fun!
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