Introduction
B4P provides means to define your own procedures and functions, assign plausible names for them and call them up like standard B4P functions. Following control flow functions are available to define your own functions:
- define procedure(): The user-defined function can only be called as a procedure in statements. Even if provided, return values are discarded.
- define function(): The user-defined function can only be called inside expressions where the returned value is used.
- define procedure and function(): The user-defined function can be called as both procedure in statements and functions inside expressions.
All three functions expect a block (inside braces) containing the code. Variables created inside are local variables. Parameters are available
as pure input parameters, output parameters, bi-directional I/O parameters, and references to variables so the whole sub-structure containing thee
the members can be accessed. Return values can be provided with the return() function call.
Additional procedure and function names can be defined on the same implementation. The local variable function name[] is visible inside the code block and
can be used to provide distinguished functionality for every additional procedure and function name. For more info, see
- define additional procedure(): Assign an additional procedure name to an existing user-specific procedure or function.
- define additional function(): Assign an additional function name to an existing user-specific procedure or function.
- define additional procedure and function(): Assign an additional name, which can be used as as procedure and function calls, to an existing user-specific procedure or function.
Fore more details, see the section on user-defined functions.
define function( hypotenuse, { { x, numeral }, { y, numeral } } )
{
return( sqrt( x[]*x[] + y[]*y[] ) );
}
define procedure( say hello ) { echo("Hello !"); }
say hello;
echo( hypotenuse(3,4) ); // 5
echo( hypotenuse(5,12) ); // 13
echo( hypotenuse(8,15) ); // 17
echo( hypotenuse(1,1) ); // 1.41... Hello !
5
13
17
1.4142135624