Expressions

The xcpp preprocessor allows for evaluation of expressions in a similar manner to the C/C++ compiler.

The following table shows the operators and their precedence (highest precedence at the top of the table):

Operator	Description
`! ~ - +`	Logical negation Bitwise negation Unary minus Unary plus
`^^`	Power
`* / %`	Multiplication Division Modulus
`+ -`	Addition Subtraction
`<< >>`	Bitwise shift left Bitwise shift right
`< <= > >=`	Comparison less-than Comparison less-than-or-equal-to Comparison greater-than Comparison greater-than-or-equal-to
`== !=`	Comparison equal-to Comparison not-equal-to
`&`	Bitwise AND
`^`	Bitwise XOR
`\|`	Bitwise OR
`&&`	Logical AND
`\|\|`	Logical OR
`? :`	Ternary conditional (if-then-else)

Expressions are evaluated in the following circumstances:

Assignment to a variable in the @let directive;
Initialising a typed formal argument when invoking a macro;
Calculating the return value when invoking a macro that has a typed return value;
The @() directive; and
Evaluation of the boolean expression in @if directives.

The supported types are bool, int, double, char and string. Unlike C/C++ there is no implicit conversion from int to bool.

Special functions

The trigonometric functions sin, cos and tan are available. Also the exponential exp, and natural logarithm log (base e).

Before translation	After translation
`@def double e = exp(1) double f() { return e; }`	`double f() { return 2.7182818284590451; }`