Resolving operators with user defined operands

A method of resolving an expression comprising an overloaded binary operator, a first operand of a first type and a second operand of a second type, comprising the steps of:

• determining a first set of types, where said first set comprises all types to which there is a widening conversion from said first type;
• determining a second set of types, where said second set comprises all types to which there is a widening conversion from said second type;
• determining a third set of types, where said third set comprises all types which result from the operation of said over binary operator on a type from among said first set and a type from among said second set;
• if said third set of types is empty, determining a fourth set of types, where said fourth set comprises all types to which there is a narrowing conversion from said first type and all types to which there is a widening conversion from said first type;
• if said third set of types is empty, determining a fifth set of types, where said fifth set comprises all types to which there is a narrowing conversion from said second type and all types to which there is a widening conversion from said second type;
• if said third set of types is empty, determining a sixth set of types, where said sixth set comprises all types which result from the operation of said over binary operator on a type from among said fourth set and a type from among said fifth set;
• if said third set of types is not empty, selecting the most encompassed type in said third set as a target type;
• and
• if said third set of types is empty, selecting the most encompassing type in said sixth set of types as said target type.

A computer-readable medium containing computer executable instructions to resolve an expression comprising an overloaded binary operator, a first operand of a first type and a second operand of a second type, the computer-executable instructions to perform acts comprising:

• determining a first set of types, where said first set comprises all types to which there is a widening conversion from said first type;
• determining a second set of types, where said second set comprises all types to which there is a widening conversion from said second type;
• determining a third set of types, where said third set comprises all types which result from the operation of said over binary operator on a type from among said first set and a type from among said second set;
• if said third set of types is empty, determining a fourth set of types, where said fourth set comprises all types to which there is a narrowing conversion from said first type and all types to which there is a widening conversion from said first type;
• if said third set of types is empty, determining a fifth set of types, where said fifth set comprises all types to which there is a narrowing conversion from said second type and all types to which there is a widening conversion from said second type;
• if said third set of types is empty, determining a sixth set of types, where said sixth set comprises all types which result from the operation of said over binary operator on a type from among said fourth set and a type from among said fifth set;
• if said third set of types is not empty, selecting the most encompassed type in said third set as a target type;
• and
• if said third set of types is empty, selecting the most encompassing type in said sixth set of types as said target type.

A operator resolution system of resolving an expression comprising an overloaded binary operator, a first operand of a first type and a second operand of a second type, comprising:

• a first set determination module for determining a first set of types, where said first set comprises all types to which there is a widening conversion from said first type;
• a second set determination module for determining a second set of types, where said second set comprises all types to which there is a widening conversion from said second type;
• a third set determination module for determining a third set of types, where said third set comprises all types which result from the operation of said over binary operator on a type from among said first set and a type from among said second set;
• a fourth set determination module for, if said third set of types is empty, determining a fourth set of types, where said fourth set comprises all types to which there is a narrowing conversion from said first type and all types to which there is a widening conversion from said first type;
• a fifth set determination module for, if said third set of types is empty, determining a fifth set of types, where said fifth set comprises all types to which there is a narrowing conversion from said second type and all types to which there is a widening conversion from said second type;
• a sixth set determination module for, if said third set of types is empty, determining a sixth set of types, where said sixth set comprises all types which result from the operation of said over binary operator on a type from among said fourth set and a type from among said fifth set;
• a most encompassed type selection module for, if said third set of types is not empty, selecting the most encompassed type in said third set as a target type;
• and
• a most encompassing type selection module for, if said third set of types is empty, selecting the most encompassing type in said sixth set of types as said target type.