Conditional structures: Difference between revisions
→{{header|langur}}: added switch
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=={{header|langur}}==
If and switch/given expressions always produce a value, even if it's nothing (null).
In the shortened forms, you dispense with the keywords (except the first one).
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<syntaxhighlight lang="langur">if .x > .y: break</syntaxhighlight>
===switch/given expressions===
Switch was added to langur 0.11. The difference between switch and given is that switch defaults to testing that any condition is true (as familiar to many programmers) and given defaults to testing that all conditions are true.
<syntaxhighlight lang="langur">
# .y == true xor .z == true
}
switch 0 {
case .x, .y: ...
# .x or .y equals 0
...
}
given .x, .y, .z {
case true: ...
# all are true
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As of 0.7, complex test expressions are evaluated once, then compared against conditions.
▲ case 7 <, 14, 21: ...
▲ # 7 < .x and .y == 14 and 21 != .z
▲ case or > 100, _, re/abc/: ...
▲ # .a > .b
▲ case _, _, == 7; xor .a <= .b: ...
▲ # .z == 7 xor .a <= .b
▲ default: ...
===implicit fallthrough===
If a block of a switch or given has any statements, there is no implicit fallthrough. A case with an empty block after it creates an implicit fallthrough.
<syntaxhighlight lang="langur">given .x {
case true:
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===explicit fallthrough from anywhere===
A fallthrough statement is allowed anywhere within a switch or given block, not just at the end.
<syntaxhighlight lang="langur">given .x {
case true:
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}</syntaxhighlight>
===shortened form switch/given===
A shortened form
<syntaxhighlight lang="langur">given(.x, .y, .z;
true: ... ; # all are equal to true
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