Boolean values: Difference between revisions
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SqrtNegInf (talk | contribs) m (→Perl: removed example of deprecated code) |
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In an <code>if</code> and similar, <code>nil</code> is false and anything else is true. To make that clear docstrings etc say "non-nil" for true. (See last item in [http://www.gnu.org/software/emacs/manual/html_node/elisp/Documentation-Tips.html elisp manual documentation tips].) |
In an <code>if</code> and similar, <code>nil</code> is false and anything else is true. To make that clear docstrings etc say "non-nil" for true. (See last item in [http://www.gnu.org/software/emacs/manual/html_node/elisp/Documentation-Tips.html elisp manual documentation tips].) |
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=={{header|EMal}}== |
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<syntaxhighlight lang="emal"> |
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logic booleanTrue = true |
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logic booleanFalse = false |
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if 2 > 1 and true and not false |
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writeLine("true: " + true + ", false: " + false) |
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end |
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if false == logic!0 |
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writeLine("explicit conversion from integer") |
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end |
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if true == logic!"⊤" |
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writeLine("explicit conversion from text") |
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end |
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</syntaxhighlight> |
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{{out}} |
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<pre> |
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true: ⊤, false: ⊥ |
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explicit conversion from integer |
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explicit conversion from text |
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</pre> |
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=={{header|Erlang}}== |
=={{header|Erlang}}== |
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Erlang doesn't technically define boolean types. Instead, the atoms <tt>true</tt> and <tt>false</tt> are used. However, they are integrated well enough into the language there should be no problem with that as long as you don't expect false and true to mean anything but literal false and true. |
Erlang doesn't technically define boolean types. Instead, the atoms <tt>true</tt> and <tt>false</tt> are used. However, they are integrated well enough into the language there should be no problem with that as long as you don't expect false and true to mean anything but literal false and true. |