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Foundations
Strict and warnings Scalar variables Array variables Hash variables Numeric context String context Undef Defined
Strings and Regex
Double quoted interpolation Single quoted strings Quoting operators Regex match Regex substitution Capture groups Named captures Transliteration
Control Flow
If elsif Unless While Until For loop Foreach Next last redo Given when concept
Lists and Arrays
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Hashes and References
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Subroutines
Sub definitions Argument list @_ Signatures Return values Lexical closures State variables Prototypes concept Wantarray
Modules and OO
Packages Use require Exporter Bless Methods Inheritance @ISA SUPER Moose concept
File and I/O
Open read Open write Three-arg open Diamond operator Filehandles Local $/ slurp File::Spec Directory handles
Errors and Processes
Die Warn Eval exception handling $@ error variable System Qx command capture Fork concept Signals %SIG
Advanced Perl
Autovivification Local vs my Our variables Tie concept Overload concept END blocks DATA handle Getopt::Long
Perl / Modules and OO

Packages

Learn packages in Perl through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.

12 min read • Intermediate

packages is an atomic Perl topic inside Modules and OO. The example uses the named construct directly so you can see its syntax, data flow, and observable behavior.

Read the code by locating the exact feature named packages, then trace the value before and after that feature runs. This lesson is intentionally isolated from neighboring topics: changing identifiers alone would not reproduce the same behavior because the construct itself is different.

Topic-specific example

perl-0049-71a65d3359.pl
perl Try It Live 
package App::User; sub name{"Ada"} package main; print App::User::name(),"\n";
Edge case / engineering note

For packages, test the boundary that makes the feature meaningful: invalid input, an empty value, a missing branch, lifecycle/cleanup, or a type/runtime constraint. Do not infer correctness only from the happy path.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

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