+// test: echo -e '{sto (1, 1 + 1), rcl (1) * 3}' | calc.exe -v 3 | grep -q 'Program'
+// test: echo -e '{sto (1, 1 + 1), rcl (1) * 3}' | calc.exe | grep -q '=> 6'
+// test: echo -e '{\n{}\n{1, 2\n{sto (1, 1 + 1),\npow(2, {sto (1, 1 + 2), 2}, {rcl(2)})\n2 {sto (1, 1 + 1)}' 2>&1 | calc.exe | grep -c error | xargs test 6 =