User manual

Section 2: TSP Programming Fundamentals Series 3700 System Switch/Multimeter Reference Manual
2-34 3700S-901-01 Rev. C / July 2008
Variables and types
TSL has six basic types: nil, boolean, number, string, function, and
table. TSL is a dynamically typed language, which means variables do not
need to be declared as a specific type. Instead, variables assume a type when a
value is assigned to them. Therefore, each value carries its own type.
If a variable has not been assigned a value, the variable defaults to the type
nil. All numbers are real numbers. There is no distinction between integers and
floating-point numbers in TSL.
var = nil
var is nil.
var = 1.0
var is now a number.
var = 0.3E-12
var is still a number.
var = 7
var is still a number.
var = "Hello world!"
var is now a string.
var = "I said, Hello world!"
var is still a string.
var = function(a, b) return(a+b)
end
var is now a function that adds two
numbers.
var = {1, 2., 3.00e0}
var is now a table (in other words, an
array) with three initialized members.
nil is a type with a single value, nil, whose main property is to be different
from any other value. Global variables have a nil value by default before a first
assignment, and you can assign nil to a global variable to delete it. TSL uses
nil as a non-value that represents the absence of a useful value.
Operators
Arithmetic operators:
+ (addition)
- (subtraction)
* (multiplication)
/ (division)
- (negation)