compilation of +

% proc one {a b} { + $a $b }; tcl::unsupported::disassemble proc one
ByteCode 0x0x15c4290, refCt 1, epoch 15, interp 0x0x15937f0 (epoch 15)
  Source " + $a $b "
  Cmds 1, src 9, inst 6, litObjs 0, aux 0, stkDepth 2, code/src 0.00
  Proc 0x0x15e9540, refCt 1, args 2, compiled locals 2
      slot 0, scalar, arg, "a"
      slot 1, scalar, arg, "b"
  Commands 1:
      1: pc 0-4, src 1-8
  Command 1: "+ $a $b "
    (0) loadScalar1 %v0 	# var "a"
    (2) loadScalar1 %v1 	# var "b"
    (4) add 
    (5) done 

% proc two {a b} { expr {$a + $b} }; tcl::unsupported::disassemble proc two
ByteCode 0x0x1672770, refCt 1, epoch 15, interp 0x0x15937f0 (epoch 15)
  Source " expr {$a + $b} "
  Cmds 1, src 16, inst 6, litObjs 0, aux 0, stkDepth 2, code/src 0.00
  Proc 0x0x15f5cf0, refCt 1, args 2, compiled locals 2
      slot 0, scalar, arg, "a"
      slot 1, scalar, arg, "b"
  Commands 1:
      1: pc 0-4, src 1-15
  Command 1: "expr {$a + $b} "
    (0) loadScalar1 %v0 	# var "a"
    (2) loadScalar1 %v1 	# var "b"
    (4) add 
    (5) done