Give the function f the attribute HoldAll:

As a result, the second and subsequent arguments are not evaluated prior to entering the (in this case nonexistent) function body:

Compare with a function g that has no attributes:

The first argument of If is always evaluated, but the others are only evaluated if that corresponding branch is entered:

This is because If has the attribute HoldRest:

Give the function inout the attribute HoldRest:

Define a function of two arguments that returns them wrapped in Hold as well as the second without wrapping:

The first argument is evaluated prior to entering the function body, while the second is evaluated inside the function body:

Implement your own conditional:

Use Evaluate to force evaluation of an argument of a HoldRest function:

Suppress the evaluation of all but the first argument of a pure function:

Sequence splitting still happens for HoldRest functions:

NHoldRest protects arguments from N, but evaluates them normally otherwise: