'is'(Result, Expression) is true if and only if evaluating Expression as an expression gives Result as a result.
| Evaluable functors | |
| (pi)/0 | Pi constant |
| (e)/0 | E constant |
| (tau)/0 | Tau constant (2*Pi) |
| (+)/2 | Addition |
| (-)/2 | Subtraction |
| (*)/2 | Multiplication |
| (//)/2 | Integer division |
| (/)/2 | Division |
| (rem)/2 | Remainder |
| (mod)/2 | Modulus |
| (+)/1 | Identity |
| (-)/1 | Negation |
| (abs)/1 | Absolute value |
| (sign)/1 | Sign |
| (float_integer_part)/1 | Integer part |
| (float_fractional_part)/1 | Fractional part |
| (float)/1 | Float coercion |
| (floor)/1 | Floor |
| (truncate)/1 | Truncate |
| (round)/1 | Round |
| (ceiling)/1 | Ceiling |
| (**)/2 | Power |
| (^)/2 | Power |
| (sin)/1 | Sine |
| (cos)/1 | Cosine |
| (tan)/1 | Tangent |
| (asin)/1 | Arc sine |
| (acos)/1 | Arc cosine |
| (atan)/1 | Arc tangent |
| (atan2)/2 | Arc tangent |
| (exp)/1 | Exponentiation |
| (log)/1 | Logarithm |
| (sqrt)/1 | Square root |
| (>>)/2 | Bitwise right shift |
| (<<)/2 | Bitwise left shift |
| (/\)/2 | Bitwise and |
| (\/)/2 | Bitwise or |
| (xor)/2 | Bitwise exclusive or |
| (\)/1 | Bitwise complement |