Tektronix Keithley 2651A Reference Manual page 295

Section 6: Instrument programming
Relational operators
Operator Description
<
less than
>
greater than
<=
less than or equal
>=
greater than or equal
~=
not equal
==
equal
Logical operators
The logical operators in Lua are and, or, and not. All logical operators consider both false and
nil as false and anything else as true.
The operator not always returns false or true.
The conjunction operator and returns its first argument if the first argument is false or nil;
otherwise, and returns its second argument. The disjunction operator or returns its first argument if
this value is different from nil and false; otherwise, or returns its second argument. Both and and
or use shortcut evaluation, that is, the second operand is evaluated only if necessary.
The example output you get may vary depending on the data format settings of the instrument.
Example
print(10 or errorqueue.next())
print(nil or "a")
print(nil and 10)
print(false and errorqueue.next())
print(false and nil)
print(false or nil)
print(10 and 20)
String concatenation
String operators
Operator
..
6-22
Model 2651A High Power System SourceMeter® Instrument Reference Manual
Description
Concatenates two strings. If either argument is a number, it is coerced to a string (in a
reasonable format) before concatenation.
1.00000e+01
a
nil
false
false
nil
2.00000e+01
2651A-901-01 Rev. C October 2021