Shulou(Shulou.com)06/01 Report--

Editor to share with you what Perl variable naming rules are, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

Variable naming rules in perl

Variable naming rules:

1. Do not have the same name as the built-in variable in perl, such as:% ARGV,$a,$b $_, etc.

Variable names in 2.perl are strictly case-sensitive

3. It is recommended to use a combination of uppercase letters, lowercase letters, numbers, and underscores to name variable names. Other special characters.

Example of variable naming

Variable names are named in the form of adjective _ noun, and multiple words are separated by an underscore, such as

$next_record$total_score$root_node

For the array or hash of the look-up table, use the naming method of xxx_of, xxx_for, that is, add a preposition at the end, for example.

My title_of;my ISBN_for;my @ sales_from

This way of writing makes the following code extremely readable.

While (my $month = prompt-menu = > $MONTH_NAMES) {for my $book (@ catalog) {print "$ISBN_for {$book} $title_of {$book}: $sales_from [$month]\ n";}}

For subroutines and methods, the grammar rules that make up names are as follows

Sub get_recordsub get_record_forsub eat_cookiesub eat_previous_cookiesub build_profilesub build_execution_profilesub build_execution_profile_using

In this way, there is little need to comment on the later code.

@ config_options = get_record_for ($next_client); for my $option (@ config_options) {build_execution_profile_using ($next_client, $option);} Boolean naming

It is generally named after the property or assertion being tested, which also makes conditional expressions read naturally. Generally speaking, most of these names start with is_ or has_, with exceptions, such as.

Sub is_valid;sub metadata_available_for;sub has_end_tag;my $loading_finished;my $has_found_bad_record

Take a look at the readability of the code that uses this rule, as shown below, which is almost self-annotated.

If (is_valid ($next_record) & &! $loading_finished) {METADATA:while (metadata_available_for ($next_record)) {pushu @ metadata, get_metadata_for ($next_record); last METADATA if has_end_tag ($next_record);}} else {$has_found_bad_record = 1;} reference variable naming

Adding _ ref to the end of the reference variable prevents it from being used as a normal variable.

Array and hash

Hashes are usually named singular, followed by prepositions, which have been mentioned earlier, while arrays are usually named plural.

Underline

The words of the name are separated by underlining.

Upper and lowercase

Subroutines, methods, variables, and tagged arguments are all lowercase.

Package and class names (IO::Controller) use mixed case.

Constants are capitalized ($SRC, $ARG).

Practical subroutine

When writing classes or modules, subroutines that are for internal use only and do not export should begin with an underscore

The above is all the content of the article "what are the naming rules of Perl variables?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.