Section 6: Instrument programming
Models 707B and 708B Switching Matrix Reference Manual
6-14
707B-901-01 Rev. B / January 2015
Example: Function
function add_two(first_value,
second_value)
return first second_value
end
print(add_two(3, 4), type(add_two))
7 function
Example: Table
atable = {1, 2, 3, 4}
print(atable, type(atable))
print(atable[1])
print(atable[4])
Defines a table with four numeric
elements.
Note that the "table" value (shown here
as
a096cd30
) will vary.
table: a096cd30 table
1
4
Delete a global variable
To delete a global variable, assign
nil
to the global variable. This removes the global variable from
the run-time environment.
Functions
With Lua, you can group commands and statements using the
function
keyword. Functions can
take zero, one, or multiple parameters, and they return zero, one, or multiple values.
You can use functions to form expressions that calculate and return a value. Functions can also act
as statements that execute specific tasks.
Functions are first-class values in Lua. That means that functions can be stored in variables, passed
as arguments to other functions, and returned as results. They can also be stored in tables.
Note that when a function is defined, it is stored in the run-time environment. Like all data that is
stored in the run-time environment, the function persists until it is removed from the run-time
environment, is overwritten, or the instrument is turned off.
Create functions using the function keyword
Functions are created with a message or in Lua code in either of the following forms:
function
myFunction
(
parameterX
)
functionBody
end
myFunction
= function (
parameterX
)
functionBody
end
Where:
•
myFunction
: The name of the function.
•
parameterX
: Parameter names. To use multiple parameters, separate the names with commas.
•
functionBody
: The code that is executed when the function is called.
