This document contains the following exercises:

• Creating a Program

• Running a Program

• Correcting Program Errors

• Stowing a Program

• Displaying Information about a Program

• Displaying the Content of the Current Library

• Setting the Editor Profile Options

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Creating a Program

You will now write your first short program which displays "Hello World!". It will be stored in the library you have created previously.

To create a new program

1. Make sure that you have logged on to the library named TUTORIAL.

2. At the bottom of the Development Functions menu, enter the following information and press ENTER:

   Code .. C Type .. P Name .. HELLO___________________________ Command ===> Enter-PF1---PF2---PF3---PF4---PF5---PF6---PF7---PF8---PF9---PF10--PF11--PF12--- Help Menu Exit Canc

   "C" stands for the function Create Object, "P" stands for the object type program, and "HELLO" is the name of the program to be created.

   Tip:
   When you enter the function code C, you can also enter an asterisk (*) in the Type field. When you press ENTER, a list of all object types and the letters that correspond to these object types is shown.

   The program editor appears. It is currently empty.

3. Enter the following code in the program editor:

   * The "Hello world!" example in Natural.
   *
   DISPLAY "Hello world!"
   END /* End of program

   Comment lines start with an asterisk (*) followed by at least one blank or a second asterisk. When you forget to enter the blank or second asterisk, Natural assumes that you have specified a system variable; this will result in an error.

   If you want to insert empty lines in your program, you should define them as comment lines. This is helpful, if you want to access your program from different platforms (Windows, mainframe or Linux and Cloud). With the mainframe version of Natural, for example, the default is that empty lines are automatically deleted when you press ENTER.

   You can also insert comments at the end of a statement line. In this case, the comment starts with a slash followed by an asterisk (/*).

   The text that is to be shown in the output is defined with the DISPLAY statement. It is enclosed in quotation marks.

   The END statement is used to mark the physical end of a Natural program. Each program must end with END.

   When you press ENTER, it may happen that all of your lower-case characters are translated to upper-case characters. This behavior is defined in the editor profile (which is explained later).

Running a Program

The system command RUN automatically invokes the system command CHECK which checks the program code for errors. If no error is found, the program is compiled on the fly and then executed.

Notes:

1. CHECK is also available as a separate command.
2. Natural also provides the system command EXECUTE which uses the stowed version of your program (stowing a program is explained later in this tutorial). In contrast to this, the RUN command always uses your latest modifications to the program.

To run a program

1. In the program editor's command line, enter one of the following:

   RUN

   R

   System commands may be abbreviated. R is the abbreviated form of RUN.

   Depending on the definitions in your environment, the command line is located either at the top or bottom of the screen.

   > RUN > + Program HELLO Lib TUTORIAL

   When your code is syntactically correct, the output contains the text you have defined.

   MORE
   Page      1                                                  13-05-16  13:27:42
   
   
   Hello world!
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

2. Press ENTER to return to the program editor.

Correcting Program Errors

You will now create an error in your Hello World program and then run the program once more.

To correct an error

1. Delete the second quotation mark in the line containing the DISPLAY statement.

2. Run the program once more as described above.

   When the error is found, an error message is displayed.

   NAT0305 Text string must begin and end on the same line. > > + Program HELLO Lib TUTORIAL All ....+....1....+....2....+....3....+....4....+....5....+....6....+....7.. 0010 * The "Hello world!" example in Natural. 0020 * E 0030 DISPLAY "HELLO WORLD! 0040 END /* End of program 0050 0060 0070 0080 0090 0100 0110 0120 0130 0140 0150 0160 0170 0180 0190 0200 ....+....1....+....2....+....3....+....4....+....5....+... S 4 L 1

   The statement line that contains the error is highlighted and marked with an "E".

3. Correct the error, that is: insert the missing quotation mark at the end of the line.

4. Run the program once more to find the next error.

   In this case, no more errors are found and the output is shown.

5. Press ENTER to return to the program editor.

Stowing a Program

When you stow a program, it is compiled and both source code and a generated program are stored in the Natural system file.

Like the RUN command, the system command STOW automatically invokes the CHECK command. A program is only stowed when it is syntactically correct.

To stow a program

• In the program editor's command line, enter the following:

  STOW

Displaying Information about a Program

The LIST command is useful to find out whether only the source code or both source code and a generated program are available for an object.

To display information about a program

1. In the program editor's command line, enter one of the following:

   LIST DIR HELLO

   L DIR HELLO

   The following screen appears. The information provided with Cataloged on is only available when the object has been stowed.

   13:15:45 ***** NATURAL LIST COMMAND ***** 2012-07-17 User SAG - List Directory - Library TUTORIAL Directory of Program HELLO Saved on ... 2012-07-17 13:15:36 ------------------------------------------------------------------------------- Library .... TUTORIAL User-ID ...... SAG Mode ....... Structured TP-System .. COMPLETE Terminal-ID .. DAEFTCA9 Op-System .. MVS/ESA Transaction .. NATvr NAT-Ver .... v.r.s Source size .......................... 100 Bytes Directory of Program HELLO Cataloged on 2012-07-17 13:15:36 ------------------------------------------------------------------------------- Library .... TUTORIAL User-ID ...... SAG Mode ....... Structured TP-System .. COMPLETE Terminal-ID .. DAEFTCA9 Op-System .. MVS/ESA Transaction .. NATvr NAT-Ver .... v.r.s Used GDA ... Size of global data ... 0 Bytes Size in DATSIZE ...... 560 Bytes Size in buffer pool ... 2620 Bytes Size of OPT-Code ...... 0 Bytes Initial OPT string .... ENTER to continue

   Note:
   In the example above, the notations vr and v.r.s stand for the current version number of Natural. See also the definition of Version in the Glossary.

2. Press ENTER to return to the program editor.

Displaying the Content of the Current Library

The LIST command can also be used to display a list of all Natural objects in the current library. This is helpful, for example, if you decide at some point during this tutorial that you want to delete one or more of your Natural objects in order to start again from the very beginning.

To display a list of Natural objects

1. In the program editor's command line, enter one of the following:

   LIST *

   L *

   The following screen appears. It lists the program you have just created.

   13:34:27 ***** NATURAL LIST COMMAND ***** 2012-07-17 User SAG - LIST Objects in a Library - Library TUTORIAL Cmd Name Type S/C SM Version User ID Date Time --- *________ *__________ *__ * *______ *________ *__________ *________ __ HELLO Program S/C S v.r.s SAG 2012-07-17 13:15:36 1 Objects found Top of List. Command ===> Enter-PF1---PF2---PF3---PF4---PF5---PF6---PF7---PF8---PF9---PF10--PF11--PF12--- Help Print Exit Sort -- - + ++ > Canc

2. To find out which commands are available, enter a question mark (?) in the Cmd column next to your program.

   The following window appears.

   +-------- COMMANDS ---------+ ! ! ! ED Edit ! ! LI List ! ! LD List Dir ! ! PR Print ! ! LE List expanded ! ! RU Run ! ! ST Stow ! ! CA Catalog ! ! DE Delete ! ! RE Rename ! ! . End ! ! ! ! ! ! ! ! ! ! ! ! __ HELLO ! +---------------------------+

3. Do not apply any changes right now. Press PF3 to close the window without specifying any command.

4. Press PF3 once more to return to the program editor.

Setting the Editor Profile Options

When working with the Natural program editor or data area editor, an editor profile can be defined per user. This tutorial uses the default settings of the editor profile named SYSTEM. Some important settings are mentioned below.

To check the editor profile options

1. In the program editor's command line, enter the following:

   PROFILE

   The following screen appears.

   13:35:43 ***** NATURAL EDITORS ***** 2012-07-17 - Editor Profile - Profile Name .. SYSTEM__ PF and PA Keys PF1 ... HELP___________ PF2 ... _______________ PF3 ... EXIT___________ PF4 ... _______________ PF5 ... _______________ PF6 ... _______________ PF7 ... -______________ PF8 ... +______________ PF9 ... _______________ PF10 .. SC=____________ PF11 .. _______________ PF12 .. CANCEL_________ PF13 .. _______________ PF14 .. _______________ PF15 .. MENU___________ PF16 .. _______________ PF17 .. _______________ PF18 .. _______________ PF19 .. --_____________ PF20 .. ++_____________ PF21 .. _______________ PF22 .. _______________ PF23 .. _______________ PF24 .. _______________ PA1 ... _______________ PA2 ... SCAN___________ PA3 ... _______________ Automatic Functions Auto Renumber .. Y Auto Save Numbers .. 0__ Source Save into .. EDITWORK Additional Options .. N Command ===> Enter-PF1---PF2---PF3---PF4---PF5---PF6---PF7---PF8---PF9---PF10--PF11--PF12--- Help Exit AddOp Save Reset Del Canc

   When a user-specific editor profile does not exist, the default profile SYSTEM is displayed. This default profile can be used to create a user-specific profile. When a user-specific profile exists already, it is displayed instead of the SYSTEM profile.

2. In the Additional Options field, enter "Y" and press ENTER.

   Or:
   Press PF4.

   The following window appears.

   +--------------------- Additional Options ----------------------+ ! ! ! ! ! + Editor Defaults ......... N ! ! + General Defaults ........ N ! ! + Color Definitions ....... N ! ! ! ! ! ! ! ! ! ! ! +---------------------------------------------------------------+

3. Enter "Y" in the fields Editor Defaults and General Defaults, and press ENTER.

   The following window appears for the editor defaults.

   +----------------------- Editor Defaults -----------------------+ | | | Escape Character for Line Command .. . | | Empty Line Suppression ............. Y | | Empty Line Suppression for Text .... N | | Source Size Information ............ N | | Source Status Message .............. Y | | Absolute Mode for SCAN/CHANGE ...... N | | Range Mode for SCAN/CHANGE ......... N | | Direction Indicator ................ + | | | +---------------------------------------------------------------+

   You can see the escape character that has been defined for line commands. This tutorial assumes that the default character, which is the a period (.), is used.

   This tutorial also assumes that the option Empty Line Suppression is set to "Y". In this case, all blank lines in the program editor are automatically deleted when you press ENTER. They are not deleted when this option is set to "N".

4. For this tutorial, you should make sure that all options are set as shown above. Press ENTER to display the next window.

   The following window appears.

   +---------------------- General Defaults -----------------------+ ! ! ! Editing in Lower Case .............. N ! ! Dynamic Conversion of Lower Case ... Y ! ! Position of Message Line ........... TOP ! ! Cursor Position in Command Line .... N ! ! Stay on Current Screen ............. N ! ! Prompt Window for Exit Function .... Y ! ! ISPF Editor as Program Editor ...... N ! ! Leave Editor with Unlock ........... N ! ! ! +---------------------------------------------------------------+

   When the option Editing in Lower Case is set to "Y" and the option Dynamic Conversion of Lower Case is set to "N", any source code remains as you enter it. This feature, however, also depends on system-environment-specific settings which may force an uppercase translation of all of your input; this cannot be influenced by Natural.

5. If desired, change the above mentioned options for lowercase conversion and press ENTER. Press ENTER once more to return to the Additional Options window, and then press ENTER again to close this window.

6. When a user-specific profile has not yet been created, overwrite the profile name SYSTEM with your user ID and press ENTER.

   When a user-specific profile exists already, proceed with the next step.

7. Press PF5 to save your changes in the database and then press PF3 to exit the editor profile.

   Note:
   Instead of pressing a PF key, you can also enter the corresponding command in the command line. For example, in the above case, you can enter the commands SAVE and EXIT.

   Or:
   If you do not want to save your changes to the database but want to use them for the current session, press PF3 to exit the editor profile.

   The exit function displays a window with different options.

   +----------- EXIT Function -----------+ ! ! ! _ Save and Exit ! ! _ Exit without Saving ! ! _ Resume Function ! ! ! ! ! +-------------------------------------+

   Select the option Exit without Saving to use the changes for the current session only.

   Or:
   If you want to exit the editor profile without keeping any changes, press PF12.

   Your program is shown again. Any new settings will now be used in the program editor (and also in the data area editor which is explained later).

You can now proceed with the next exercises: Database Access.