Matvec Users’ Guide

Chapter 7
User-Defined Function
7.1 Syntax
function obj.foo(args) { }
function foo(args) { }
protected function obj.foo(args) { }
protected function foo(args) { }
7.2 Description
User-defined functions in Matvec can be constructed or defined) by the above four forms. The first form is
so-called a user-defined member function with respect to object obj, whereas the second form is so-called a
user-defined friend function. The third and fourth are the same as the first two except that functions are
protected. In another word function definition in the last two forms can not be overwritten.
Usually, the definition of a user-defined functions are stored in a disk file. Before calling them, we have
to load them into the computer memory using the Matvec builtin function input:
input("")
User-defined functions in Matvec are treated as objects, in a manner similar to other objects such as
Matrix, Vector. Thus, in principle, users can assign/copy them like ordinary variables, but users should
avoid to use this feature.
By default all variables within a function are global except those symbolic arguments in function header
and those declared in local statements: local(A,B,C,...);
Note that local statement can appear anywhere only within function definition, and multiple local statements
are also allowed.
Function execution will terminated right after return statement. the returning value of a function is the
last expression evaluated in the function execution. The return statement in the function is optional.
7.3 Scope
7.4 Recursion
not working yet so far.
7.5 Examples
protected function A.sign()
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