3.1 Functions


The following chapters are also part of the topic "functions":

  3.1.1   �Internal�operators�&�functions�
  3.1.2   �Include�user�functions���������
  3.1.3   �EBNF-Syntax��������������������

A function in Graph2D has to consist of the following parts:

Name

A function needs a name. The name must not contain leading figures or space
and mus not exceed an length of 30 chars. You may use (international)
chars, figures (not at first position) and the apostroph "'".

Argument list

The name is followed by an argument list in bracktes "(" ")". The list
consists of (many) variable names seperated by colons ",". The variable
names must follow the same conventions as the function names. A variable
must not appear twice or more in an argument list. The list can also be
empty - in this case you do not even have to write the brackets. Name and
argument-list together are called "functionheader".

"="

Between functionheader and functiontext you must place an "="...

Function text

The definition of the function-text follows the "usual" rules for the
notation of mathematical terms. Graph2D is case-sensitive! The functiontext
may consist of:

  - Operators  see also chapter  internal�Operators

  - Functions  see also chapter  internal�Functions

    You also can  include other user-defined functions out of the function-
    list into one of your functions. You can do this even if the function
    to be included does not yet exist at the time you include it.

  - Constantes

    A Constante is e real number in the range �9.22337177E18

  - Variables

    Of course you can use only those variables in a function you did
    define in the argument-list of the function.


Examples for correct functions:

  "p(x)=x^2+98",
  "Sum(a,b)=a+b",
  "g=9.81",
  "f(x)=sin(x^2)+1/2*x",
  "function23a(iks,yps,zett)=iks^yps*zett+(-1.23+1.0356E-5)"