Difference between revisions of "PERL/C3/Perl-Module-Library-(CPAN)/English-timed"

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| 00:16
 
| 00:16
 
|To record this tutorial, I am using:
 
|To record this tutorial, I am using:
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* '''Ubuntu Linux''' 12.04 operating system
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'''Ubuntu Linux''' 12.04 operating system
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* '''Perl''' 5.14.2 and
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'''Perl''' 5.14.2 and
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* ''''gedit' Text Editor'''.
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''''gedit' Text Editor'''.
  
 
|-
 
|-
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| 00:43
 
| 00:43
 
|'''Modules: '''
 
|'''Modules: '''
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* These are code files that contain common routines  
+
These are code files that contain common routines  
−
* That are written by different authors
+
That are written by different authors
−
* And, can be used by several programs at a time.
+
And, can be used by several programs at a time.
  
 
|-
 
|-
 
| 00:55
 
| 00:55
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|'''CPAN'''
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|'''CPAN:'''PERL is an '''open source''' language and anyone can contribute to PERL's standard '''CPAN library'''.
−
 
+
−
* PERL is an '''open source''' language and anyone can contribute to PERL's standard '''CPAN library'''.
+
  
 
|-
 
|-
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|01:09
 
|01:09
 
|The official website of '''CPAN '''is:
 
|The official website of '''CPAN '''is:
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www.cpan.org
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'''www.cpan.org'''
  
 
|-
 
|-
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|-
 
|-
 
| 01:32
 
| 01:32
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|Type:''' perldoc List colon colon Util'''
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|Type:''' perldoc List colon colon Util'''.
  
 
|-
 
|-
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|-
 
|-
 
| 01:46
 
| 01:46
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|This indicates, you need to install the '''perl hyphen doc package.'''
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|This indicates, you need to install the '''perl hyphen doc''' package.
  
 
|-
 
|-
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|-
 
|-
 
| 02:08
 
| 02:08
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|Note that the documentation contains-  
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|Note that the documentation contains-
−
 
+
description of the module,  
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* description of the module,  
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example of how to use it  
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* example of how to use it  
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and an '''overview'''.
−
* and an overview.
+
  
 
|-
 
|-
 
|02:20
 
|02:20
 
|Hit the 'Q' key to exit the '''perldoc viewer'''.
 
|Hit the 'Q' key to exit the '''perldoc viewer'''.
−
 
  
 
|-
 
|-
 
|02:25
 
|02:25
−
|Next, we will see how to use''' List colon colon Util module''' in a '''Perl''' program.
+
|Next, we will see how to use''' List colon colon Util''' module in a '''Perl''' program.
  
 
|-
 
|-
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|-
 
|-
 
| 02:50
 
| 02:50
−
|'''use List colon colon Util''' tells '''Perl''' to find and load the '''module List colon colon Util.'''
+
|'''use List colon colon Util''' tells '''Perl''' to find and '''load''' the module '''List colon colon Util.'''
  
 
|-
 
|-
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| 03:32
 
| 03:32
 
|The most popular '''subroutines '''available in''' List colon colon Util''' are:
 
|The most popular '''subroutines '''available in''' List colon colon Util''' are:
−
 
+
'''first''' - which returns the first '''element''' in the '''list'''.
−
'''first''' - which returns the first element in the list.
+
  
 
|-
 
|-
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|-
 
|-
 
| 04:02
 
| 04:02
−
|'''shuffle''' – returns the values of the input in a random order.
+
|'''shuffle''' – this returns the values of the '''input''' in a random order.
  
 
|-
 
|-
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|-
 
|-
 
| 04:40
 
| 04:40
−
|Switch back to the''' terminal''' and type:  '''perl exist underscore modules dot pl''' and press''' Enter'''.
+
|Switch back to the terminal and type:  '''perl exist underscore modules dot pl''' and press''' Enter'''.
  
 
|-
 
|-
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|-
 
|-
 
| 04:58
 
| 04:58
−
|Next we will see how to create new '''Perl modules''' and add it to '''CPAN'''.
+
|Next, we will see how to create a new '''Perl module''' and add it to '''CPAN'''.
  
 
|-
 
|-
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|-
 
|-
 
| 05:14
 
| 05:14
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| Document the module.
+
| '''Document''' the module.
  
 
|-
 
|-
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|-
 
|-
 
| 05:43
 
| 05:43
−
|Basically, it creates skeleton files for the module.
+
|Basically, it creates skeleton files for the module.''' hyphen PAX''' are options that omit '''autoload''' and '''autogenerate'''.
−
''' hypen PAX''' are options that omit '''autoload''' and '''autogenerate'''.
+
  
 
|-
 
|-
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|-
 
|-
 
| 06:12
 
| 06:12
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|Type: '''h2xs hyphen PAXn Math colon colon Simple'''
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|Type: '''h2xs hyphen PAXn Math colon colon Simple'''.
  
 
|-
 
|-
 
| 06:20
 
| 06:20
−
|The '''h2xs program''' generates all these files required to distribute the '''module'''.
+
|The '''h2xs''' program generates all these files required to distribute the module.
  
 
|-
 
|-
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|-
 
|-
 
| 06:49
 
| 06:49
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|The "Changes" file is where we will keep track of changes made to our module when we write new versions.
+
|The "Changes" file is where we will keep track of changes, made to our module, when we write new versions.
  
 
|-
 
|-
 
| 06:58
 
| 06:58
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|'''lib subdirectory '''contains the '''module'''.
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|'''lib subdirectory '''contains the module.
  
 
|-
 
|-
 
| 07:02
 
| 07:02
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|'''MANIFEST''' contains a list of files in this '''directory'''.
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|'''MANIFEST''' contains a list of files in this directory.
  
 
|-
 
|-
 
| 07:07
 
| 07:07
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|'''Makefile''' is a '''Perl '''program used to create a '''Unix Makefile'''.  
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|'''Makefile''' is a Perl program used to create a '''Unix Makefile'''.  
 
|-
 
|-
 
| 07:12
 
| 07:12
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|We will use this '''Makefile''' to test and install our '''module'''.
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|We will use this '''Makefile''' to test and install our module.
  
 
|-
 
|-
 
| 07:18
 
| 07:18
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|Test scripts will be in''' t subdirectory.'''
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|'''Test script'''s will be in''' 't' subdirectory.'''
  
 
|-
 
|-
 
| 07:22
 
| 07:22
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|The tests are simple '''Perl scripts''' but with a''' dot t''' extension used for '''unit testing'''.
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|The '''tests''' are simple '''Perl scripts''', but with a''' dot t extension''' used for '''unit testing'''.
  
 
|-
 
|-
 
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| 07:30
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|'''Simple.pm''' is our '''module'''.
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|'''Simple.pm''' is our module.
  
 
|-
 
|-
 
| 07:34
 
| 07:34
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|All these files are generated automatically when we execute the '''h2xs command.'''
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|All these files are generated automatically when we execute the '''h2xs''' command.
  
 
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|-
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|-
 
|-
 
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| 07:45
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|Change the '''directory''' to''' lib forward slash Math'''
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|Change the directory to''' lib forward slash Math'''.
  
 
|-
 
|-
 
| 07:51
 
| 07:51
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|Now we will open the''' simple.pm''' file to see the existing content.
+
|Now, we will open the''' simple.pm''' file to see the existing content.
  
 
|-
 
|-
 
| 07:57
 
| 07:57
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|Type:''' gedit Simple.pm'''
+
|Type:''' gedit Simple.pm'''.
  
 
|-
 
|-
 
| 08:02
 
| 08:02
−
|What we see here is a documented functional '''Perl module '''that doesn't do anything.
+
|What we see here is a documented, functional Perl module that doesn't do anything.
  
 
|-
 
|-
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|-
 
|-
 
| 08:16
 
| 08:16
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|Add the below code after the text,''' Preloaded methods go here.'''
+
|Add the below code after the text: "Preloaded methods go here".
  
 
|-
 
|-
 
| 08:22
 
| 08:22
−
|Here we will add four subroutines''' add, subtract, multiply '''and '''divide'''.
+
|Here, we will add four subroutines''' add, subtract, multiply '''and '''divide'''.
  
 
|-
 
|-
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|-
 
|-
 
| 08:33
 
| 08:33
−
|Now, let's create a sample Perl program to test our code that make sure it is working properly.
+
|Now, let's create a sample Perl program to test our code that makes sure it is working properly.
  
 
|-
 
|-
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|-
 
|-
 
| 08:55
 
| 08:55
−
|Add the following code after the existing code, '''“Insert your test code below”,'''
+
|Add the following code after the existing code: “Insert your test code below..”.
  
 
|-
 
|-
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|-
 
|-
 
| 09:10
 
| 09:10
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|Let us '''run''' the test script.
+
|Let us '''run''' the '''test script'''.
  
 
|-
 
|-
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|-
 
|-
 
| 09:19
 
| 09:19
−
|We see this error message because the '''Perl '''script cannot find '''Simple.pm''' in its directory.
+
|We see this '''error''' message because the '''Perl '''script cannot find '''Simple.pm''' in its directory.
  
 
|-
 
|-
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|-
 
|-
 
| 09:43
 
| 09:43
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|'''Perl modules '''and '''libraries '''can be loaded from these directories.
+
|Perl modules and '''libraries '''can be loaded from these directories.
  
 
|-
 
|-
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|-
 
|-
 
| 09:57
 
| 09:57
−
|Alternately, we can add files to''' at the rate INC''' at runtime using''' -I''' option.
+
|Alternately, we can add files to''' at the rate INC''' at run time using '-I' option.
  
 
|-
 
|-
 
| 10:06
 
| 10:06
−
|Now let us switch to the '''terminal'''.
+
|Now, let us switch to the terminal.
  
 
|-
 
|-
 
| 10:10
 
| 10:10
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|I will '''execute''' the program using the -I '''command line parameter'''.
+
|I will '''execute''' the program using the''' '-I' command line parameter'''.
  
 
|-
 
|-
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| 11:02
 
| 11:02
 
|In this tutorial, we learnt to:
 
|In this tutorial, we learnt to:
−
* Use existing '''modules'''
+
Use existing modules  
−
* Create new '''modules'''
+
Create new modules and how to use in the Perl program.
−
and how to use in the Perl program.
+
  
 
|-
 
|-
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|-
 
|-
 
| 11:24
 
| 11:24
−
| '''Text colon colon Wrap''' module has a variable-''' columns.''' Set the''' columns''' value to''' 30.'''
+
| '''Text colon colon Wrap''' module has a variable- "columns". Set the''' columns''' value to 30.
  
 
|-
 
|-
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|-
 
|-
 
| 11:35
 
| 11:35
−
|The video at the following link summarises the Spoken Tutorial project.
+
|The video at the following link summarizes the '''Spoken Tutorial''' project.Please download and watch it.
−
Please download and watch it.
+
  
 
|-
 
|-
 
| 11:42
 
| 11:42
 
|The''' Spoken Tutorial Project''' team:
 
|The''' Spoken Tutorial Project''' team:
−
* conducts workshops using spoken tutorials  
+
conducts workshops using spoken tutorials and gives certificates on passing online tests.
−
* and gives certificates on passing online tests.
+
  
 
|-
 
|-

Latest revision as of 17:45, 5 October 2017

Time Narration
00:01 Welcome to the Spoken Tutorial on how to use Perl Module Library i.e. CPAN
00:08 In this tutorial, we will learn to use existing modules and create new modules in PERL.
00:16 To record this tutorial, I am using:

Ubuntu Linux 12.04 operating system Perl 5.14.2 and 'gedit' Text Editor.

00:28 You can use any text editor of your choice.
00:32 To follow this tutorial, you should have working knowledge of Perl programming.
00:37 If not, then go through the relevant Perl spoken tutorials on the spoken tutorial website.
00:43 Modules:

These are code files that contain common routines That are written by different authors And, can be used by several programs at a time.

00:55 CPAN:PERL is an open source language and anyone can contribute to PERL's standard CPAN library.
01:03 CPAN has thousands of ready-to-use modules written by different authors.
01:09 The official website of CPAN is:

www.cpan.org

01:17 We will take List colon colon Util as an example and see how to use it.
01:24 This gives me access to the functions which are already written inside this module.
01:30 Switch to the terminal.
01:32 Type: perldoc List colon colon Util.
01:38 You may get an error saying You need to install the perl hyphen doc package to use this program.
01:46 This indicates, you need to install the perl hyphen doc package.
01:50 Do so using Synaptic Package Manager.
01:55 Please refer to the relevant Linux spoken tutorials on the spoken tutorial website.
02:01 What you see here is the documentation for the List colon colon Util module.
02:08 Note that the documentation contains-

description of the module, example of how to use it and an overview.

02:20 Hit the 'Q' key to exit the perldoc viewer.
02:25 Next, we will see how to use List colon colon Util module in a Perl program.
02:33 Let me open a sample program exist underscore modules.pl which I have already saved.
02:40 In your exist underscore modules dot pl file, type the following code as displayed on the screen.
02:47 Let us understand the code now.
02:50 use List colon colon Util tells Perl to find and load the module List colon colon Util.
03:00 qw() function extracts words out of the string using a delimiter and returns the words as a list.
03:09 It is just a quick way of declaring an array.
03:13 While importing a module, it imports only the subroutines specified in the list into our program.
03:21 It contains general-utility list of subroutines.
03:26 The module will export its subroutines and variables into our program.
03:32 The most popular subroutines available in List colon colon Util are:

first - which returns the first element in the list.

03:42 max –this returns the highest numerical value in the list.
03:47 maxstr- returns the highest string in the list.
03:52 min- this returns the lowest numerical value.
03:57 minstr – returns the lowest string in the list.
04:02 shuffle – this returns the values of the input in a random order.
04:08 sum – returns the numerical sum of all the elements in the list.
04:14 There is no need to write separate source code for each function.
04:18 We can just make use of these available subroutines in our program.
04:23 These are the inputs I am passing to the function max, min, sum and shuffle.
04:30 And, these are the print statements.
04:33 Now, press Ctrl+S to save the file.
04:37 Let us execute the program.
04:40 Switch back to the terminal and type: perl exist underscore modules dot pl and press Enter.
04:49 Observe the output.
04:51 In Random number, you may get any value between 0 and 51.
04:58 Next, we will see how to create a new Perl module and add it to CPAN.
05:04 Below are the steps to create a module:
05:08 Create a place to develop the module.
05:11 Create skeleton files for the module.
05:14 Document the module.
05:16 Write the Perl code.
05:18 Write the code for testing.
05:20 Distribute the module in CPAN.
05:24 Perl is distributed with a program called h2xs which is used to generate files for a new module.
05:32 Math colon colon Simple specifies our module name.
05:37 This is used to generate the directory which should clearly identify the module it contains.
05:43 Basically, it creates skeleton files for the module. hyphen PAX are options that omit autoload and autogenerate.
05:54 Let's create a new module- Math colon colon Simple.
05:59 It will be provided with simple functions: add, subtract, multiply and divide.
06:06 Let us switch to terminal to execute the h2xs command.
06:12 Type: h2xs hyphen PAXn Math colon colon Simple.
06:20 The h2xs program generates all these files required to distribute the module.
06:27 Let us change directory to Math hyphen Simple.
06:33 Note the directory path on your machine. It may be as Math forward slash Simple.
06:41 Type "ls" to list all the files in the directory. We can see the following files.
06:49 The "Changes" file is where we will keep track of changes, made to our module, when we write new versions.
06:58 lib subdirectory contains the module.
07:02 MANIFEST contains a list of files in this directory.
07:07 Makefile is a Perl program used to create a Unix Makefile.
07:12 We will use this Makefile to test and install our module.
07:18 Test scripts will be in 't' subdirectory.
07:22 The tests are simple Perl scripts, but with a dot t extension used for unit testing.
07:30 Simple.pm is our module.
07:34 All these files are generated automatically when we execute the h2xs command.
07:41 Let us open the simple.pm file.
07:45 Change the directory to lib forward slash Math.
07:51 Now, we will open the simple.pm file to see the existing content.
07:57 Type: gedit Simple.pm.
08:02 What we see here is a documented, functional Perl module that doesn't do anything.
08:09 We have to write the required functions in this file to make it do something.
08:16 Add the below code after the text: "Preloaded methods go here".
08:22 Here, we will add four subroutines add, subtract, multiply and divide.
08:29 Now, press Ctrl+S to save the file.
08:33 Now, let's create a sample Perl program to test our code that makes sure it is working properly.
08:41 Let us open the test file Math-Simple.t under the subdirectory 't'.
08:49 Type: gedit Math-Simple.t
08:55 Add the following code after the existing code: “Insert your test code below..”.
09:02 The Print statements will print the output.
09:06 Now, press Ctrl+S to save the file.
09:10 Let us run the test script.
09:13 Type: perl Math-simple.t and press Enter.
09:19 We see this error message because the Perl script cannot find Simple.pm in its directory.
09:27 It should look inside the lib directory. How can we rectify this error?
09:33 Let us see a few options for this.
09:37 At the rate INC is a special variable that contains a list of directories.
09:43 Perl modules and libraries can be loaded from these directories.
09:48 This line of code tells the Perl program to add this directory path to its at the rate INC search directory.
09:57 Alternately, we can add files to at the rate INC at run time using '-I' option.
10:06 Now, let us switch to the terminal.
10:10 I will execute the program using the '-I' command line parameter.
10:16 So, I will type: perl -Ilib t/Math-Simple.t
10:24 Here is the output as expected.
10:27 We have tested the module and it is working fine.
10:31 Final step is to distribute the module.
10:34 The general procedure for installing module is to run these commands.
10:40 Installation involves copying files into the Perl library directory.
10:45 Most of us don't have permission to copy into this directory.
10:49 Since Math-Simple isn't a very useful module, I am not demonstrating the installation part.
10:57 This brings us to the end of this tutorial. Let us summarize.
11:02 In this tutorial, we learnt to:

Use existing modules Create new modules and how to use in the Perl program.

11:11 Here is an assignment for you.
11:13 Use the Text colon colon Wrap module.
11:17 Make use of the Wrap() function which wraps the input text to form neat paragraphs.
11:24 Text colon colon Wrap module has a variable- "columns". Set the columns value to 30.
11:31 Print the text to see the formatted output.
11:35 The video at the following link summarizes the Spoken Tutorial project.Please download and watch it.
11:42 The Spoken Tutorial Project team:

conducts workshops using spoken tutorials and gives certificates on passing online tests.

11:51 For more details, please write to us.
11:55 Spoken Tutorial project is funded by NMEICT, MHRD, Government of India.
12:02 More information on this mission is available at this link.
12:06 This is Nirmala Venkat from IIT Bombay, signing off. Thanks for watching.

Contributors and Content Editors

PoojaMoolya, Sandhya.np14

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