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< title > File Class – Wren< / title >
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< h1 > < a href = "../../" > wren< / a > < / h1 >
< h2 > a classy little scripting language< / h2 >
< / div >
< / div >
< / header >
< div class = "page" >
< nav class = "big" >
< ul >
< li > < a href = "../" > Modules< / a > < / li >
< li > < a href = "./" > io< / a > < / li >
< / ul >
< section >
< h2 > io classes< / h2 >
< ul >
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< li > < a href = "directory.html" > Directory< / a > < / li >
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< li > < a href = "file.html" > File< / a > < / li >
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< li > < a href = "file-flags.html" > FileFlags< / a > < / li >
< li > < a href = "stat.html" > Stat< / a > < / li >
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< li > < a href = "stdin.html" > Stdin< / a > < / li >
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< li > < a href = "stdout.html" > Stdout< / a > < / li >
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< / ul >
< / section >
< / nav >
< nav class = "small" >
< table >
< tr >
< td > < a href = "../" > Modules< / a > < / td >
< td > < a href = "./" > io< / a > < / td >
< / tr >
< tr >
< td colspan = "2" > < h2 > io classes< / h2 > < / td >
< / tr >
< tr >
< td >
< ul >
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< li > < a href = "directory.html" > Directory< / a > < / li >
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< li > < a href = "file.html" > File< / a > < / li >
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< li > < a href = "file-flags.html" > FileFlags< / a > < / li >
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< / ul >
< / td >
< td >
< ul >
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< li > < a href = "stat.html" > Stat< / a > < / li >
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< li > < a href = "stdin.html" > Stdin< / a > < / li >
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< li > < a href = "stdout.html" > Stdout< / a > < / li >
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< / ul >
< / td >
< / tr >
< / table >
< / nav >
< main >
< h1 > File Class< / h1 >
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< p > Lets you work with files on the file system. An instance of this class
represents an open file with a file descriptor. < / p >
< p > When you are done with a file object, it’ s a good idea to explicitly close it.
If you don’ t, the GC will close it when the file is no longer used and gets
finalized, but that may take a while. In the meantime, leaving it open wastes
a file descriptor. < / p >
< h2 > Static Methods < a href = "#static-methods" name = "static-methods" class = "header-anchor" > #< / a > < / h2 >
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< h3 > File.< strong > create< / strong > (path, fn) < a href = "#file.create(path,-fn)" name = "file.create(path,-fn)" class = "header-anchor" > #< / a > < / h3 >
< p > Opens the file at < code > path< / code > for writing and passes it to < code > fn< / code > . If there is already
a file at that path, it is truncated. After the function returns, the file is
automatically closed. < / p >
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< div class = "codehilite" > < pre > < span > < / span > < span class = "vg" > File< / span > < span class = "o" > .< / span > < span class = "n" > create< / span > < span class = "p" > (< / span > < span class = "s" > " numbers.txt" < / span > < span class = "p" > )< / span > < span class = "p" > {< / span > < span class = "o" > |< / span > < span class = "n" > file< / span > < span class = "o" > |< / span >
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< span class = "n" > file< / span > < span class = "o" > .< / span > < span class = "n" > writeBytes< / span > < span class = "p" > (< / span > < span class = "s" > " one two three" < / span > < span class = "p" > )< / span >
< span class = "p" > }< / span >
< / pre > < / div >
< h3 > File.< strong > delete< / strong > (path) < a href = "#file.delete(path)" name = "file.delete(path)" class = "header-anchor" > #< / a > < / h3 >
< p > Deletes the file at < code > path< / code > . < / p >
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< h3 > File.< strong > exists< / strong > (path) < a href = "#file.exists(path)" name = "file.exists(path)" class = "header-anchor" > #< / a > < / h3 >
< p > Whether a regular file exists at < code > path< / code > . This returns < code > false< / code > for directories
or other special file system entities. < / p >
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< h3 > File.< strong > open< / strong > (path, fn) < a href = "#file.open(path,-fn)" name = "file.open(path,-fn)" class = "header-anchor" > #< / a > < / h3 >
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< p > Opens the file at < code > path< / code > for reading and passes it to < code > fn< / code > . After the function
returns, the file is automatically closed. < / p >
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< div class = "codehilite" > < pre > < span > < / span > < span class = "vg" > File< / span > < span class = "o" > .< / span > < span class = "n" > open< / span > < span class = "p" > (< / span > < span class = "s" > " words.txt" < / span > < span class = "p" > )< / span > < span class = "p" > {< / span > < span class = "o" > |< / span > < span class = "n" > file< / span > < span class = "o" > |< / span >
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< span class = "n" > file< / span > < span class = "o" > .< / span > < span class = "n" > readBytes< / span > < span class = "p" > (< / span > < span class = "mi" > 5< / span > < span class = "p" > )< / span >
< span class = "p" > }< / span >
< / pre > < / div >
< h3 > File.< strong > read< / strong > (path) < a href = "#file.read(path)" name = "file.read(path)" class = "header-anchor" > #< / a > < / h3 >
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< p > Reads the entire contents of the file at < code > path< / code > and returns it as a string. < / p >
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< div class = "codehilite" > < pre > < span > < / span > < span class = "vg" > File< / span > < span class = "o" > .< / span > < span class = "n" > read< / span > < span class = "p" > (< / span > < span class = "s" > " words.txt" < / span > < span class = "p" > )< / span >
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< / pre > < / div >
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< p > No encoding or decoding is done. If the file is UTF-8, then the resulting
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string will be a UTF-8 string. Otherwise, it will be a string of bytes in
whatever encoding the file uses. < / p >
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< h3 > File.< strong > realPath< / strong > (path) < a href = "#file.realpath(path)" name = "file.realpath(path)" class = "header-anchor" > #< / a > < / h3 >
< p > Resolves < code > path< / code > , traversing symlinks and removining any unneeded < code > ./< / code > and < code > ../< / code >
components. Returns the canonical absolute path to the file. < / p >
< div class = "codehilite" > < pre > < span > < / span > < span class = "k" > var< / span > < span class = "n" > path< / span > < span class = "o" > =< / span > < span class = "s" > " /some/./symlink/a/../b/file.txt" < / span >
< span class = "vg" > System< / span > < span class = "o" > .< / span > < span class = "n" > print< / span > < span class = "p" > (< / span > < span class = "vg" > File< / span > < span class = "o" > .< / span > < span class = "n" > realPath< / span > < span class = "p" > (< / span > < span class = "n" > path< / span > < span class = "p" > ))< / span > < span class = "output" > /real/path/a/file.txt< / span >
< / pre > < / div >
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< h3 > File.< strong > size< / strong > (path) < a href = "#file.size(path)" name = "file.size(path)" class = "header-anchor" > #< / a > < / h3 >
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< p > Returns the size in bytes of the contents of the file at < code > path< / code > . < / p >
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< h2 > Constructors < a href = "#constructors" name = "constructors" class = "header-anchor" > #< / a > < / h2 >
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< h3 > File.< strong > create< / strong > (path) < a href = "#file.create(path)" name = "file.create(path)" class = "header-anchor" > #< / a > < / h3 >
< p > Opens the file at < code > path< / code > for writing. If there is already a file at that path,
it is truncated. < / p >
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< div class = "codehilite" > < pre > < span > < / span > < span class = "k" > var< / span > < span class = "n" > file< / span > < span class = "o" > =< / span > < span class = "vg" > File< / span > < span class = "o" > .< / span > < span class = "n" > create< / span > < span class = "p" > (< / span > < span class = "s" > " colors.txt" < / span > < span class = "p" > )< / span >
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< span class = "n" > file< / span > < span class = "o" > .< / span > < span class = "n" > writeBytes< / span > < span class = "p" > (< / span > < span class = "s" > " chartreuse lime teal" < / span > < span class = "p" > )< / span >
< span class = "n" > file< / span > < span class = "o" > .< / span > < span class = "n" > close< / span > < span class = "p" > ()< / span >
< / pre > < / div >
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< h3 > File.< strong > open< / strong > (path) < a href = "#file.open(path)" name = "file.open(path)" class = "header-anchor" > #< / a > < / h3 >
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< p > Opens the file at < code > path< / code > for reading. You are responsible for closing it when
done with it. < / p >
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< h2 > Methods < a href = "#methods" name = "methods" class = "header-anchor" > #< / a > < / h2 >
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< h3 > < strong > descriptor< / strong > < a href = "#descriptor" name = "descriptor" class = "header-anchor" > #< / a > < / h3 >
< p > The numeric file descriptor used to access the file. < / p >
< h3 > < strong > isOpen< / strong > < a href = "#isopen" name = "isopen" class = "header-anchor" > #< / a > < / h3 >
< p > Whether the file is still open or has been closed. < / p >
< h3 > < strong > size< / strong > < a href = "#size" name = "size" class = "header-anchor" > #< / a > < / h3 >
< p > The size of the contents of the file in bytes. < / p >
< h3 > < strong > close< / strong > () < a href = "#close()" name = "close()" class = "header-anchor" > #< / a > < / h3 >
< p > Closes the file. After calling this, you can read or write from it. < / p >
< h3 > < strong > readBytes< / strong > (count) < a href = "#readbytes(count)" name = "readbytes(count)" class = "header-anchor" > #< / a > < / h3 >
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< p > Reads up to < code > count< / code > bytes starting from the beginning of the file. < / p >
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< div class = "codehilite" > < pre > < span > < / span > < span class = "c1" > // Assume this file contains " I am a file!" .< / span >
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< span class = "vg" > File< / span > < span class = "o" > .< / span > < span class = "n" > open< / span > < span class = "p" > (< / span > < span class = "s" > " example.txt" < / span > < span class = "p" > )< / span > < span class = "p" > {< / span > < span class = "o" > |< / span > < span class = "n" > file< / span > < span class = "o" > |< / span >
< span class = "vg" > System< / span > < span class = "o" > .< / span > < span class = "n" > print< / span > < span class = "p" > (< / span > < span class = "n" > file< / span > < span class = "o" > .< / span > < span class = "n" > readBytes< / span > < span class = "p" > (< / span > < span class = "mi" > 6< / span > < span class = "p" > ))< / span > < span class = "output" > I am a< / span >
< span class = "p" > }< / span >
< / pre > < / div >
< h3 > < strong > readBytes< / strong > (count, offset) < a href = "#readbytes(count,-offset)" name = "readbytes(count,-offset)" class = "header-anchor" > #< / a > < / h3 >
< p > Reads up to < code > count< / code > bytes starting at < code > offset< / code > bytes from the beginning of
the file. < / p >
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< div class = "codehilite" > < pre > < span > < / span > < span class = "c1" > // Assume this file contains " I am a file!" .< / span >
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< span class = "vg" > File< / span > < span class = "o" > .< / span > < span class = "n" > open< / span > < span class = "p" > (< / span > < span class = "s" > " example.txt" < / span > < span class = "p" > )< / span > < span class = "p" > {< / span > < span class = "o" > |< / span > < span class = "n" > file< / span > < span class = "o" > |< / span >
< span class = "vg" > System< / span > < span class = "o" > .< / span > < span class = "n" > print< / span > < span class = "p" > (< / span > < span class = "n" > file< / span > < span class = "o" > .< / span > < span class = "n" > readBytes< / span > < span class = "p" > (< / span > < span class = "mi" > 6< / span > < span class = "p" > ,< / span > < span class = "mi" > 2< / span > < span class = "p" > ))< / span > < span class = "output" > am a f< / span >
< span class = "p" > }< / span >
< / pre > < / div >
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< h3 > < strong > writeBytes< / strong > (bytes) < a href = "#writebytes(bytes)" name = "writebytes(bytes)" class = "header-anchor" > #< / a > < / h3 >
< p > Writes the raw bytes of the string < code > bytes< / code > to the end of the file. < / p >
< h3 > < strong > writeBytes< / strong > (bytes, offset) < a href = "#writebytes(bytes,-offset)" name = "writebytes(bytes,-offset)" class = "header-anchor" > #< / a > < / h3 >
< p > Writes the raw bytes of the string < code > bytes< / code > to the to the file, starting at
< code > offset< / code > . Any overlapping bytes already in the file at the offset are
overwritten. < / p >
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< / main >
< / div >
< footer >
< div class = "page" >
< div class = "main-column" >
< p > Wren lives
< a href = "https://github.com/munificent/wren" > on GitHub< / a >
— Made with ❤ by
< a href = "http://journal.stuffwithstuff.com/" > Bob Nystrom< / a > and
< a href = "https://github.com/munificent/wren/blob/master/AUTHORS" > friends< / a > .
< / p >
< div class = "main-column" >
< / div >
< / footer >
< / body >
< / html >
