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Perl - In Perl, any value that would look like
"" or "0" if evaluated in a string context. Since undefined values evaluate to "", all undefined values are false, but not all false values are undefined.
Perl - Cite This Source - This Definition - Browse Related Terms: array context, Boolean, Boolean context, conditional, context, list context, numeric context, overloading, scalar context, string context, TMTOWTDI, void context
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Perl - An uncaught "exception", which causes termination of the "process" after printing a message on your "standard error" stream. Errors that happen inside an eval are not fatal. Instead, the eval terminates after placing the exception message in the
$@ ($EVAL_ERROR) variable. You can try to provoke a fatal error with the die operator (known as throwing or raising an exception), but this may be caught by a dynamically enclosing eval. If not caught, the die becomes a fatal error.
Perl - Cite This Source - This Definition - Browse Related Terms: errno, Error, exception, exception handling, line number, standard error, STDERR, warning
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Perl - A named collection of data, usually stored on disk in a "directory" in a "filesystem". Roughly like a document, if you're into office metaphors. In modern filesystems, you can actually give a file more than one name. Some files have special properties, like directories and devices.
Perl - Cite This Source - This Definition - Browse Related Terms: core dump, current working directory, directory handle, filesystem, home directory, named pipe, Root, RTFM, working directory
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Perl - An identifier (not necessarily related to the real name of a file) that represents a particular instance of opening a file until you close it. If you're going to open and close several different files in succession, it's fine to open each of them with the same filehandle, so you don't have to write out separate code to process each file.
Perl - Cite This Source - This Definition - Browse Related Terms: Filename, Identifier, Link, logical operator, Path, pathname, qualified, regular file, symbolic link
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Perl - One name for a file. This name is listed in a "directory", and you can use it in an open to tell the "operating system" exactly which file you want to open, and associate the file with a "filehandle" which will carry the subsequent identity of that file in your program, until you close it.
Perl - Cite This Source - This Definition - Browse Related Terms: filehandle, Identifier, Link, logical operator, Path, pathname, qualified, regular file, symbolic link
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Perl - A built-in unary operator that you use to determine whether something is "true" about a file, such as
-o $filename to test whether you're the owner of the file.
Perl - Cite This Source - This Definition - Browse Related Terms: descriptor, Directory, executable file, file descriptor, header file, NFS, slurp, stat structure, truncating, UID
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Perl - A method of storing numbers in "scientific notation", such that the precision of the number is independent of its magnitude (the decimal point "floats"). Perl does its numeric work with floating-point numbers (sometimes called "floats"), when it can't get away with using integers. Floating-point numbers are mere approximations of real numbers.
Perl - Cite This Source - This Definition - Browse Related Terms: AV, CV, GV, HV, I.V., mode, monger, NV, pad, RV
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Perl - The generic names by which a "subroutine" knows its arguments. In many languages, formal arguments are always given individual names, but in Perl, the formal arguments are just the elements of an array. The formal arguments to a Perl program are
$ARGV[0], $ARGV[1], and so on. Similarly, the formal arguments to a Perl subroutine are ExpertGlossary::Source::PerlPerlglossary=HASH(0x4d1c680), $_[1], and so on. You may give the arguments individual names by assigning the values to a my list. See also "actual arguments".
Perl - Cite This Source - This Definition - Browse Related Terms: actual arguments, argument, call by reference, call-by-value, function, parameter, prototype, subroutine, variadic