Teledyne LeCroy CATC Scripting Language Reference Manual - Manual (Page 10)

C HAPTER 3
Expressions CATC Scripting Language
6
C
HAPTER
3: E
XPRESSIONS
An expression is a statement that calculates a value. The simplest type of expression
is assignment:
x = 2
The expression x = 2 calculates 2 as the value of x.
All expressions contain operators, which are described in Chapter 4, Operators, on
page 9. The operators indicate how an expression should be evaluated in order to
arrive at its value. For example
x + 2
says to add 2 to x to find the value of the expression. Another example is
x > 2
which indicates that x is greater than 2. This is a Boolean expression, so it will
evaluate to either true or false. Therefore, if x = 3, then x > 2 will evaluate to
true; if x = 1, it will return false.
True is denoted by a non-zero integer (any integer except 0), and false is a zero
integer (0). True and false are also supported for lists (an empty list is false, while
all others are true), and strings (an empty string is false, while all others are true),
and null is considered false. However, all Boolean operators will result in integer
values.
select expression
The select expression selects the value to which it evaluates based on Boolean
expressions. This is the format for a select expression:
select {
<expression1> : <statement1>
<expression2> : <statement2>
...
};
The expressions are evaluated in order, and the statement that is associated with the
first true expression is executed. That value is what the entire expression evaluates
to.