Controlling when an expression is evaluated lets you generate the actual variable names at run-time. This can produce extremely concise code, particularly compared to the C language equivalent. In the following example, a set of simple objects each has a value. The object name and its value is entered. In a conventional language, we might search the array of objects to find the one with the given name, and then make the assignment. Gamma makes it possible to directly construct the variable reference using the set function, as follows:

Gamma> name = "fido";
"fido"
Gamma> value = "bites";
"bites"
Gamma> set(symbol(string(name)), value);
"bites"
Gamma> fido;
"bites"
	  

Note that the syntax does not accept the = assignment operator, so the functional form of the assignment operator: set must be used. Note also that we would probably use undefined_p to verify that the variable actually existed to avoid halting the program due to an undefined variable error. Although the example is trivial, this technique is very useful for constructing function references based on run-time data.