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1 select expression, 1 selec – Teledyne LeCroy LeCroy Analyzers File Based Decoding Manual User Manual

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Chapter 3: Expressions

File-based Decoding User Manual

8

LeCroy Corporation

3.1 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 {

:

:

...

};

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.

x = 10

Value_of_x = select {

x < 5 : "Less than 5";

x >= 5 : "Greater than or equal to 5";

};

The above expression evaluates to “Greater than or equal to 5” because the first true
expression is x >= 5. Note that a semicolon is required at the end of a select
expression because it is not a compound statement and can be used in an expression
context.

There is also a keyword default, which in effect always evaluates to true. An example
of its use is

Astring = select {

A == 1 : "one";

A == 2 : "two";

A == 3: "three";

A > 3 : "overflow";

default : null;

};

If none of the first four expressions evaluates to true, then default is evaluated,
returning a value of null for the entire expression.

select

expressions can also be used to conditionally execute statements, similar to C

switch

statements:

select {

A == 1 : DoSomething();

A == 2 : DoSomethingElse();

default: DoNothing();

};

In this case the appropriate function is called depending on the value of A, but the
evaluated result of the select expression is ignored.