MACROMEDIA DIRECTOR MX-LINGO DICTIONARY, Руководство пользователя

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Chapter 3 120
case
Syntax
case expression of
expression1 : Statement
expression2 :
multipleStatements
.
.
.
expression3 , expression4 :
Statement
{otherwise:
statement(s) }
end case
Description
Keyword; starts a multiple branching logic structure that is easier to write than repeated
if...then
statements.
Lingo compares the value in
case expression
to the expressions in the lines beneath it, starting
at the beginning and continuing through each line in order, until Lingo encounters an expression
that matches
case expression
.
When Lingo finds a matching expression, it executes the corresponding statement or statements
that follow the colon after the matching expression. When only one statement follows the matching
expression, the matching expression and its corresponding statement may appear on the same line.
Multiple statements must appear on indented lines immediately below the matching expression.
When more than one possible match could cause Lingo to execute the same statements, the
expressions must be separated by commas. (The syntax line containing
expression3
and
expresssion4
is an example of such a situation.)
After Lingo encounters the first match, it stops testing for additional matches.
If the optional
otherwise
statement is included at the end of the case structure, the statements
following
otherwise
are executed if there are no matches.
If a
case
statement tests cases that aren’t all integer constants, the Export Xtra for Java converts
the
case
statement to an
if...then
statement.
Examples
The following handler tests which key the user pressed most recently and responds accordingly.
•
If the user pressed A, the movie goes to the frame labeled Apple.
•
If the user pressed B or C, the movie performs the specified transition and then goes to the
frame labeled Oranges.
•
If the user pressed any other key, the computer beeps.
on keyDown
case (the key) of
"A": go to frame "Apple"
"B", "C":
puppetTransition 99
go to frame "Oranges"
otherwise beep
end case
end keyDown