Using function names as function arguments

Because function names are ColdFusion variables, you can pass a function's name as an argument to another function. This technique allows a function to use another function as a component. For example, a calling page can call a calculation function, and pass it the name of a function that does some subroutine of the overall function.

This way, the calling page could use a single function for different specific calculations, such as calculating different forms of interest. The initial function provides the framework, while the function whose name is passed to it can implement a specific algorithm that is required by the calling page.

The following simple example shows this use. The binop function is a generalized function that takes the name of a function that performs a specific binary operation and two operands. The binop function simply calls the specified function and passes it the operands. This code defines a single operation function, the sum function. A more complete implementation would define multiple binary operations.

<cfscript>
function binop(operation, operand1, operand2)
{ return (operation(operand1, operand2)); }
function sum(addend1, addend2)
{ return addend1 + addend2;}
x = binop(sum, 3, 5);
writeoutput(x);
</cfscript>

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