How can I show that the Ruby `for` loop is in fact implemented using the `each` method?

Question

In the book Eloquent Ruby (page 21, first edition, sixth printing), the author (Russ Olsen) advocates using the each method instead of

Answer 1

How can I show the Ruby for loop is in fact implemented using the each method?

Look at the bytecode.

ruby --dump insns -e 'for n in 1..10; puts n; end'

Which prints

== disasm: @>==========
== catch table
| catch type: break  st: 0002 ed: 0006 sp: 0000 cont: 0006
|------------------------------------------------------------------------
local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
[ 2] n          
0000 trace            1                                               (   1)
0002 putobject        1..0
0004 send             >
0006 leave            
== disasm: @>=
== catch table
| catch type: redo   st: 0006 ed: 0013 sp: 0000 cont: 0006
| catch type: next   st: 0006 ed: 0013 sp: 0000 cont: 0013
|------------------------------------------------------------------------
local table (size: 2, argc: 1 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
[ 2] ?     
0000 getlocal_OP__WC__0 2                                             (   1)
0002 setlocal_OP__WC__1 2
0004 trace            256
0006 trace            1
0008 putself          
0009 getlocal_OP__WC__1 2
0011 opt_send_without_block 
0013 trace            512
0015 leave            

As you can see it calls each with a block on the first 0004 line.