Source code in the jq programming language

def typeof:
  if type == "object" and has("type") then .type else type end;

def pp:
  if type == "object" and has("type") then "\(.type)::\(.value)"
  else .
  end;

def smallint(i): i as $i
  | if (i|type) == "number" and i == (i|floor) and i > 0 and i < 11 then {"type": "smallint", "value": i}
     else empty 
     end ;

# A convenience function to save typing:
def s(i): smallint(i);

# To convert from the pretty-print representation back to smallint:
def tosmallint:
  if type == "string" and startswith("smallint::") then
     split("::") | smallint( .[1] | tonumber )
  else empty
  end ;

def add(a;b): smallint(a.value + b.value);
def minus(a;b): smallint(a.value - b.value);
def times(a;b): smallint(a.value * b.value);
def mod(a;b): smallint(a.value % b.value);
def divide(a;b): smallint( (a.value / b.value) | floor );

s(1) < s(3)            # => true
add( s(1); s(2)) | pp  # "smallint::3"
add( s(6); s(6))       # (nothing)