* let / set / define / $ / $& / @  (print evaluates; echo is literal)
V1 in 0 DC 2
R1 in out 1k
R2 out 0 1k
.op
.control
  run
  let x = 2 + 3
  print x                       $ -> 5
  set foo = hello
  echo "foo is" $foo            $ echo: literal text + $var expansion
  let v = 7
  echo "v ampersand:" $&v       $ -> 7
  define sq(y) y*y
  print sq(4)                   $ -> 16
  print @R1[resistance]         $ device param (print, not echo)
  print v(out)                  $ -> 1 (divider of 2V)
.endc
.end
