ruby + =和= +之间的差异

Posted 2021-05-16

Ripper.tokenize("a += 1")
# => ["a", " ", "+=", " ", "1"] 

pp Ripper.sexp "a += 1"
#[:program,
# [[:opassign,
#   [:var_field, [:@ident, "a", [1, 0]]],
#   [:@op, "+=", [1, 2]],
#   [:@int, "1", [1, 5]]]]]

iseq = RubyVM::InstructionSequence.compile("a += 1")
puts iseq.disasm

#== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
#local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, keyword: 0@3] s1)
#[ 2] a          
#0000 trace            1                                               (   1)
#0002 getlocal_OP__WC__0 2
#0004 putobject_OP_INT2FIX_O_1_C_ 
#0005 opt_plus         <callinfo!mid:+, argc:1, ARGS_SKIP>
#0007 dup              
#0008 setlocal_OP__WC__0 2
#0010 leave       

Ripper.tokenize("a = a +  1")
#  => ["a", " ", "=", " ", "a", " ", "+", "  ", "1"] 

pp Ripper.sexp "a = a + 1"
#[:program,
# [[:assign,
#   [:var_field, [:@ident, "a", [1, 0]]],
#   [:binary, [:var_ref, [:@ident, "a", [1, 4]]], :+, [:@int, "1", [1, 8]]]]]]


iseq = RubyVM::InstructionSequence.compile("a = a + 1")
puts iseq.disasm

#== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
#local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, keyword: 0@3] s1)
#[ 2] a          
#0000 trace            1                                               (   1)
#0002 getlocal_OP__WC__0 2
#0004 putobject_OP_INT2FIX_O_1_C_ 
#0005 opt_plus         <callinfo!mid:+, argc:1, ARGS_SKIP>
#0007 dup              
#0008 setlocal_OP__WC__0 2
#0010 leave            

OP_ASGN		: `+=' | `-=' | `*=' | `/=' | `%=' | `**='
		| `&=' | `|=' | `^=' | `<<=' | `>>='
	      	| `&&=' | `||='

# File lib/irb/ruby-lex.rb, line 338
@OP.def_rules("+=", "-=", "*=", "**=",
              "&=", "|=", "^=", "<<=", ">>=", "||=", "&&=") do
  |op, io|
  @lex_state = EXPR_BEG
  op =~ /^(.*)=$/
  Token(TkOPASGN, $1)
end