ISVARIABLE

Purpose:

Determines whether a variable or function is defined as the specified type.

ISVARIABLE("name", vartype)

"name"

A string, the variable name.

vartype

Optional. An integer, the type of variable:

1:	Global Variable (default)
2:	Local Variable
3:	Loaded User Function (SPL)
4:	Hot Variable
5:	Formal Variable (function argument)
6:	Window
7:	Nonlocal Variable
10:	Built-in Function
11:	Static Variable

A 1 if the function or variable exists as specified, else returns a 0.

a = grand(100, 0.01)

b := max(a)

isvariable(a,1) == 1

isvariable(b,1) == 1

isvariable(b,4) == 1

isvariable(b,2) == 0

isvariable("fft",10) == 1

isvariable("myfft",10) == 0

Note that all hot variables are global variables.

The following macros are defined in system.mac:

isglobal(v) isvariable(v,1)

islocal(v) isvariable(v,2)

isspl(v) isvariable(v,3)

ishotvar(v) isvariable(v,4)

isformal(v) isvariable(v,5)

isnonlocal(v) isvariable(v,7)

isbuiltin(v) isvariable(v,10)

isstatic(v) isvariable(v,11)

ISVARIABLE and ARGC are useful in detecting optional arguments to an SPL function.

ISVARIABLE can be abbreviated ISVAR.