// test: echo -e 'set (1, 2)\npop\npush (3)\nput (5, -1)\nlen\nshow\nget (3)\nquit' | calc.exe -n -v 3 | grep -q bye
// test: echo -e 'put\nget\nget (1)\npop\nput (0)' | calc.exe | grep -c 'error' | xargs test 5 =
// test: echo -e 'prog (1, {set (1, 2), push (arg (1)), show})\ncall (1, 10)\nprog (1, {mem (1), sto (1, cos (arg (1)))})\ncall (1, pi / 2)\ndel (1)' | calc.exe -n | grep -q 'stack: 1 2 10'
// test: echo -e 'prog (1, {set (1, 2), push (arg (1)), show});\ncall (1, 10);\nshow\ndel (1)' | calc.exe -n | grep -q 'stack:$'
// test: echo -e 'prog (1, {set (1, 2), push (arg (1)), show});\ncall (1, 10);\nlen' | calc.exe -n | grep -q '=> 0'
// test: echo -e 'prog (1, {mem (2), sto (1, arg (1) - rcl (1) / 2)})\ncall (1, 1)\ncall (1, 2)\ncall (1, 3)\nprog (1, {mem (2), sto (2, rcl (1)), sto (1, arg (1)), rcl (2)})\ncall (1, 10)' | calc.exe -n | grep -q '=> 2.25'
// test: echo -e 'set (1, 2)\npop\npush (3)\nput (5, -1)\nlen\nshow\nget (3)\nquit' | calc.exe -n -v 3 | grep -q bye
// test: echo -e 'put\nget\nget (1)\npop\nput (0)' | calc.exe | grep -c 'error' | xargs test 5 =
// test: echo -e 'prog (1, {set (1, 2), push (arg (1)), show})\ncall (1, 10)\nprog (1, {mem (1), sto (1, cos (arg (1)))})\ncall (1, pi / 2)\ndel (1)' | calc.exe -n | grep -q 'stack: 1 2 10'
// test: echo -e 'prog (1, {set (1, 2), push (arg (1)), show});\ncall (1, 10);\nshow\ndel (1)' | calc.exe -n | grep -q 'stack:$'
// test: echo -e 'prog (1, {set (1, 2), push (arg (1)), show});\ncall (1, 10);\nlen' | calc.exe -n | grep -q '=> 0'
// test: echo -e 'prog (1, {mem (2), sto (1, arg (1) - rcl (1) / 2)})\ncall (1, 1)\ncall (1, 2)\ncall (1, 3)\nprog (1, {mem (2), sto (2, rcl (1)), sto (1, arg (1)), rcl (2)})\ncall (1, 10)' | calc.exe -n | grep -q '=> 2.25'