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switch Another flow control command |
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Usage |
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switch [-p] (<expression>)
{
case(<value>)[:]<command>
[break]
case(<value>)[:]<command>
[break]
....
match(<wildcard_expression>)[:]<command>
[break]
....
regexp(<regular_expression>)[:]<command>
[break]
....
case(<value>)[:]<command>
[break]
....
default[:]<command>
[break]
} |
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Description |
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The switch command is based on the standard C 'switch' keyword.
It conditionally executes groups of commands chosen from a larger set of command groups. First <expression> is evaluated (<expression> is any arithmetic or string expression). Then the 'match', 'regexp', 'case' and 'default' labels are evaluated sequentially in the order of appearance. case(<value>)[:]<command> The <value> is evaluated and is compared against the result of <expression>. String comparison is case insensitive. If <value> is equal to <expression> then <command> is executed. Please note that <command> must be either a single instruction or an instruction block enclosed in braces. During or after <command> execution, if a break statement is encountered the execution of the switch is terminated, otherwise the next label is evaluated. If the -p (--passthrough) option is enabled, than the switch command will execute all the instructions blocks until a break statement is found. match(<value>)[:]<command> The <value> is expected to be a wildcard expression (wildcard characters being '*' and '?') that is matched in a case insensitive fashion against <expression>. If a match occurs, the related <command> is executed. The break statement is treated as in the case label. regexp(<value>)[:]<command> The <value> is expected to be a complete standard regular expression that is matched in a case insensitive fashion against <expression>. If a match occurs, the related <command> is executed. The break statement is treated as in the case label. default[:]<command> The default label is executed unconditionally if no previous label terminated execution with the break statement. |
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Switches |
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Examples |
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# Try to change the 1 below to 2 or 3 to see the results
%tmp = 1
switch(%tmp)
{
case(1):
echo \%tmp was 1!
break;
case(2)
echo \%tmp was 2!
break;
default:
echo \%tmp was not 1 nor 2: it was %tmp!
break;
}
# A more complex example: change the 1 in 2 or 3
%tmp = 1
switch(%tmp)
{
case(1):
echo \%tmp was 1!
case(2)
echo \%tmp was 2!
break;
default:
echo \%tmp was either 1 or something different from 2 (%tmp)
break;
}
# An example of the -p switch
%tmp = 1
switch -p (%tmp)
{
case(1):
echo \%tmp was 1!
case(2)
echo \%tmp was 1 or 2!
break;
default:
echo \%tmp was not 1 or 2 (%tmp)
break;
}
# An example with strings
%tmp = "This is a test"
%tmp2 = "This is not a test"
switch(%tmp)
{
case(%tmp2)
echo \%tmp == \%tmp2
break;
case(%tmp)
{
//do not break here
echo "Yeah... It's stupid... \%tmp == \%tmp :D"
}
match("*TEST"):
echo "Matched *TEST"
regexp("[a-zA-Z ]*test"):
echo "Matched [a-zA-Z ]*text"
regexp("[a-zA-Z ]*not[a-zA-Z ]*"):
echo "Matched [a-zA-Z ]*not[a-zA-Z ]*"
default:
echo This is executed anyway (unless some break was called)
break;
}
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