Perl Pocket Reference, 5th Edition

Miscellaneous

defined expr†

Tests whether the scalar expression has an actual value.

do { expr ; . . . }

Executes the block and returns the value of the last expression. See also the section Statements.

do filename

Executes filename as a Perl script. See also require in page 16.

eval { expr ; . . . }

Executes the code between { and }. Traps runtime errors as described with eval(expr) in page 30.

local [ our ] variable

Gives a temporary value to the named package variable, which lasts until the enclosing block, file, or eval exits. variable may be a scalar, an array, a hash, or an element (or slice) of an array or hash.

my varlist

varlist is a variable, or parenthesized list of variables. Creates a scope for the variables lexically local to the enclosing block, file, or eval.

my [ class ] varlist [ attributes ]

Experimental. Built-in attribute is :shared. Module Attribute::Handlers can be used to define additional attributes.

our varlist

Declares the variables to be a valid global within the enclosing block, file, or eval.

our [ class ] varlist [ attributes ]

Experimental. Built-in attributes are :shared and :unique. Module Attribute::Handlers can be used to define additional attributes.

ref expr†

Returns the referent type if expr is a reference. Returns the package name if expr has been blessed into a package.

reset [ expr ]

expr is a string of single letters. All variables in the current package beginning with one of those letters are reset to their pristine state. If expr is omitted, resets