Undefined values: Difference between revisions
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Native storage types work under different rules, since most native types cannot represent failure, or even undefinedness. Any attempt to assign a value to a storage location that cannot represent a failure will cause an exception to be thrown. |
Native storage types work under different rules, since most native types cannot represent failure, or even undefinedness. Any attempt to assign a value to a storage location that cannot represent a failure will cause an exception to be thrown. |
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=={{header|Phix}}== |
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Phix has a special unassigned value, that can be tested for using object(). (There is no offical way to "un-assign" a variable, though you could fairly easily do so with a bit of inline assembly.) |
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<lang Phix>object x |
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procedure test() |
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if object(x) then |
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puts(1,"x is an object\n") |
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else |
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puts(1,"x is unassigned\n") |
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end if |
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end procedure |
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test() |
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x = 1 |
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test()</lang> |
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{{out}} |
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<pre> |
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x is unassigned |
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x is an object |
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</pre> |
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=={{header|PHP}}== |
=={{header|PHP}}== |
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