Extract file extension: Difference between revisions
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Drkameleon (talk | contribs) (obsolete) |
(add Standard ML) |
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/etc/pam.d/login -> </pre> |
/etc/pam.d/login -> </pre> |
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Note: the task's description seems wrong to me; on a Unix machine, files beginning with "." are treated as hidden files (eg. in ls) and the suffix can be considered to be empty. As opposed to "a.desktop". |
Note: the task's description seems wrong to me; on a Unix machine, files beginning with "." are treated as hidden files (eg. in ls) and the suffix can be considered to be empty. As opposed to "a.desktop". |
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=={{header|Standard ML}}== |
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This just demonstrates how to functionally extend the built-in function to the alpha-numeric restriction. Since file names starting with '.' are supposed to be "hidden" files in Unix, they're not considered as an extension. |
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<lang sml>fun fileExt path : string = |
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getOpt (Option.composePartial (Option.filter (CharVector.all Char.isAlphaNum), OS.Path.ext) path, "") |
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val tests = [ |
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"http://example.com/download.tar.gz", |
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"CharacterModel.3DS", |
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".desktop", |
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"document", |
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"document.txt_backup", |
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"/etc/pam.d/login" |
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] |
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val () = app (fn s => print (s ^ " -> \"" ^ fileExt s ^ "\"\n")) tests</lang> |
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{{out}} |
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<pre>http://example.com/download.tar.gz -> "gz" |
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CharacterModel.3DS -> "3DS" |
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.desktop -> "" |
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document -> "" |
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document.txt_backup -> ""</pre> |
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=={{header|Tcl}}== |
=={{header|Tcl}}== |
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