TweetFollow Us on Twitter

Pascal Like Modula2
Volume Number:2
Issue Number:5
Column Tag:Pascal Procedures

Making Pascal Act Like Modula2

By Steve Rabalais, Rabalais Computing, Tempe, AZ

Seperate Compilation with TML Pascal

In order to develop large applications for the MacIntosh, it is desirable to have the capability to seperate your code into easily manageable pieces. This allows for modular programming and avoids having to compile all of your program each time which can be time consuming and frustrating for small changes. This article presents a procedure for doing this using the TML Pascal compiler.

Theory

The MDS linker (or Consulair's 'smart' linker) will take seperate 'REL' files containing the proper linkage information and combine them to create a stand alone application. What this procedure does is to describe the process of creating these 'REL' files. Basically, each module is a seperate Pascal program. The trick is to get the link files created properly so that the seperate modules will link together if one is changed and re-compiled.

Example Program

The example program below consists of three (3) seperate modules representing three segments of a single application. The first module (X_mod1.Pas) is the 'main' program. It contains the compiler directives necessary to create a 'LINK' text file for the LINKER. External references in segments are satisfied with:

1. Include statements for standard symbols and declarations. (ie. {$I quickdraw.ipas.}.)

2. Include statements for program globals (ie. {$I X_globals.ipas})

3. EXTERNAL procedure references.

The external references will allow the compiler to 'assume' the procedure exists and generate the appropriate temporary code. The actual addresses will be satisfied at link time.

Scenario

The following scenario describes the compile/edit cycle for the example:

1. Compile X_mod1.Pas.

2 Compile X_mod2.Pas.

3. Compile X_mod3.Pas.

4. Link X_mod1.Link. (generated by X_mod1.Pas)

5. Run the application and discover a problem with X_mod2.Pas.

6. Edit X_mod2.Pas and compile 'only' X_mod2.Pas.

7. Link x_mod1.Link

8. Verify application runs properly.

Hints

These hints are a result of experience.

1. Occasionally an unidentified character will 'creep' into a text file which the compiler cannot recognize. The Pascal statement will look correct but the compiler will not accept it. To see the offending character, use the 'SHOW INVISIBLES' option in the MDS editor. It is usually a 'box looking' character. Just delete it.

2. Since the 'main' program module creates the LINKER file, you have to 'force' the compiler to generate the linker code for the runtime packages that are used in the other modules. (ie $PAS files). This is done by putting in a Pascal statement in the main program that will invoke a runtime package. Example .. 'Concat' will invoke the runtime package $PAS$Str package).

Epilogue

This procedure will allow you to create an application of essentially an unlimited size using the TML Pascal compiler. For large applications, this procedure is essential. It is good programming practice to plan ahead.


PROGRAM X_mod1(Input,Output);

{$I MemTypes.ipas}
{$I QuickDraw.ipas}
{$I OSIntf.ipas}
{$I ToolIntf.ipas}
{$I PackIntf.ipas}

{$T APPL RABS}
{$B+}

{$I  X_globals.ipas}

{$U< X_mod2/Code}
{$U< X_mod3/Code}

PROCEDURE   P_mod1_proc1 (v_var1 : Str255) ; FORWARD;
 PROCEDURE P_mod2_proc1 (v_var1 : Str255) ; EXTERNAL;
 PROCEDURE P_mod3_proc1 (v_var1 : Str255) ; EXTERNAL;
PROCEDURE   P_mod1_proc2 (v_var1 : Str255) ; FORWARD; 

{====================================}
{== P_mod1_proc1 (v_var1 : Str255) ==}
{====================================}
PROCEDURE P_mod1_proc1;
BEGIN
  writeln (v_var1);
  writeln ('In P_mod1_proc1');
END;

{===================================}
{== P_mod1_proc2 (v_var1 :Str255) ==}
{===================================}
PROCEDURE P_mod1_proc2;
BEGIN
  writeln (v_var1);
  writeln ('In P_mod1_proc2');
END;

{===========================}
{== execution begins here ==}
{===========================}
BEGIN
  g_global1 := 000;
  REPEAT
    P_mod1_proc1 ('From mod1_main');
    P_mod2_proc1 ('From mod1_main');
    P_mod3_proc1 ('From mod1_main');
    writeln;
    writeln      ('Type a 999 to quit, any other number to loop');
    Readln       (g_global1);
  UNTIL (g_global1 = 999);
END.

PROGRAM X_mod2(Input,Output);

{$I MemTypes.ipas}
{$I QuickDraw.ipas}
{$I OSIntf.ipas}
{$I ToolIntf.ipas}
{$I PackIntf.ipas}

{$I X_globals.ipas}

PROCEDURE   P_mod2_proc1 (v_var1 : Str255); FORWARD ;
PROCEDURE   P_mod3_proc1 (v_var1 : Str255); EXTERNAL;
PROCEDURE   P_mod2_proc2 (v_var1 : Str255); FORWARD ;

 
{$S Code}
{====================================}
{== P_mod2_proc1 (v_var1 : Str255) ==}
{====================================}
PROCEDURE P_mod2_proc1;
BEGIN
  writeln (v_var1);
  writeln ('In P_mod2_proc1');
END;

{====================================}
{== P_mod2_proc2 (v_var1 : Str255) ==}
{====================================}
PROCEDURE P_mod2_proc2;
BEGIN
  writeln (v_var1);
  writeln ('In P_mod2_proc2');
END;

{$S main}
{==========}
{== main ==}
{==========}
BEGIN
  {------------------------}
  {-- Dummy main program --}
  {------------------------}
END.

PROGRAM X_mod3(Input,Output);

{$I MemTypes.ipas}
{$I QuickDraw.ipas}
{$I OSIntf.ipas}
{$I ToolIntf.ipas}
{$I PackIntf.ipas}

{$I X_globals.ipas}

PROCEDURE     P_mod3_proc1 (v_var1 : Str255); FORWARD;
  PROCEDURE   P_mod1_proc1 (v_var1 : Str255); EXTERNAL;
  PROCEDURE   P_mod2_proc1 (v_var1 : Str255); EXTERNAL;
PROCEDURE     P_mod3_proc2 (v_var1 : Str255); FORWARD;

 
{$S Code}
{====================================}
{== P_mod3_proc1 (v_var1 : Str255) ==}
{====================================}
PROCEDURE P_mod3_proc1;
BEGIN
  writeln (v_var1);
  writeln ('In P_mod3_proc1');
END;

{====================================}
{== P_mod3_proc2 (v_var1 : Str255) ==}
{====================================}
PROCEDURE P_mod3_proc2;
BEGIN
  writeln (v_var1);
  writeln ('In P_mod3_proc2');
END;

{$S main}
{==========}
{== main ==}
{==========}
BEGIN
  {------------------------}
  {-- Dummy main program --}
  {------------------------}
END.

{==============================================}
{== application globals available to all segments ==}
{==============================================}
VAR
  g_global1 : INTEGER ;
  g_global2 : Rect    ;
  g_global3 : LONGINT ;



]

!PAS$Xfer

X_Mod1
PAS$Sys
OSTraps
ToolTraps
PackTraps
< 
X_mod2/Code
< 
X_mod3/Code
PAS$StdIO
Dec2Str
Str2Dec
/Bundle
/Type 'APPL' 'RABS'
$ 

Fig. 1 Combined program output

 
AAPL
$112.65
Apple Inc.
+3.24
MSFT
$47.52
Microsoft Corpora
+1.78
GOOG
$511.10
Google Inc.
+6.21

MacTech Search:
Community Search:

Software Updates via MacUpdate

Mellel 3.3.7 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
ScreenFlow 5.0.1 - Create screen recordi...
Save 10% with the exclusive MacUpdate coupon code: AFMacUpdate10 Buy now! ScreenFlow is powerful, easy-to-use screencasting software for the Mac. With ScreenFlow you can record the contents of your... Read more
Simon 4.0 - Monitor changes and crashes...
Simon monitors websites and alerts you of crashes and changes. Select pages to monitor, choose your alert options, and customize your settings. Simon does the rest. Keep a watchful eye on your... Read more
BBEdit 11.0.2 - Powerful text and HTML e...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more
ExpanDrive 4.2.1 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
Adobe After Effects CC 2014 13.2 - Creat...
After Effects CC 2014 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous After Effects customer). After Effects CS6 is still available... Read more
Command-C 1.1.7 - Clipboard sharing tool...
Command-C is a revolutionary app which makes easy to share your clipboard between iOS and OS X using your local WiFi network, even if the app is not currently opened. Copy anything (text, pictures,... Read more
Tidy Up 4.0.2 - Find duplicate files and...
Tidy Up is a complete duplicate finder and disk-tidiness utility. With Tidy Up you can search for duplicate files and packages by the owner application, content, type, creator, extension, time... Read more
Typinator 6.3 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
GraphicConverter 9.5 - Graphics editor w...
GraphicConverter is an all-purpose image-editing program that can import 200 different graphic-based formats, edit the image, and export it to any of 80 available file formats. The high-end editing... Read more

Latest Forum Discussions

See All

Shift - Photo Filters Designed By You (...
Shift - Photo Filters Designed By You 1.0 Device: iOS Universal Category: Photography Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Elastic Drums (Music)
Elastic Drums 1.0 Device: iOS iPhone Category: Music Price: $3.99, Version: 1.0 (iTunes) Description: *** Introduction price 3,99$ instead of 7,99$ *** Elastic Drums is a music app with 6 channels of synthesized drum sounds, a step... | Read more »
Fireworks Simulator (Games)
Fireworks Simulator 1.0.8 Device: iOS Universal Category: Games Price: $.99, Version: 1.0.8 (iTunes) Description: *** 50% discount – For a short time only *** You can play Fireworks Simulator on these devices: - iPhone 5, 5s, 5c, 6,... | Read more »
Nicky's Gift (Games)
Nicky's Gift 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: Everybody! Merry Christmas! There's 48 levels in the game. Let's go! Nicky's Gift | Read more »
The Hit List — Simply Powerful Tasks, To...
The Hit List — Simply Powerful Tasks, To-Dos, Projects, & Reminders 2.0 Device: iOS iPhone Category: Productivity Price: $9.99, Version: 2.0 (iTunes) Description: >> LAUNCH SPECIAL: The Hit List 2 for iPhone is ONLY $9.99... | Read more »
Mahjong Journey Review
Mahjong Journey Review By Jennifer Allen on December 18th, 2014 Our Rating: :: STEADY MATCHINGiPad Only App - Designed for the iPad Aimed at the more laid back gamer, Mahjong Journey isn’t for everyone, but those looking for some... | Read more »
Emoji Type - custom keyboard with predic...
Emoji Type - custom keyboard with predictive emojis 0.4.0 Device: iOS iPhone Category: Utilities Price: $.99, Version: 0.4.0 (iTunes) Description: Emoji Type is custom keyboard for iOS 8 that auto suggests emojis as you type. ABOUT... | Read more »
Game of the Year 2014 – 148Apps Staff Pi...
The end of 2014 is almost here, which can only mean one thing. Okay it can mean a lot of things, but in this specific context it means Game of the Year lists! Which is why the 148Apps staff have all picked their favorites from the past year. And why... | Read more »
UponPixels Review
UponPixels Review By Jennifer Allen on December 18th, 2014 Our Rating: :: CREATIVE TYPOGRAPHYUniversal App - Designed for iPhone and iPad Add cool typography and objects to your photos with the easy to use UponPixels.   | Read more »
The Vikings are Coming! CastleStorm’s Ne...
The Vikings are Coming! CastleStorm’s New Update Adds a Survival Mode Posted by Jessica Fisher on December 18th, 2014 [ permalink ] | Read more »

Price Scanner via MacPrices.net

Save up to $400 on MacBooks with Apple Certif...
The Apple Store has Apple Certified Refurbished 2014 MacBook Pros and MacBook Airs available for up to $400 off the cost of new models. An Apple one-year warranty is included with each model, and... Read more
Save up to $300 on Macs, $30 on iPads with Ap...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
iOS and Android OS Targeted by Man-in-the-Mid...
Cloud services security provider Akamai Technologies, Inc. has released, through the company’s Prolexic Security Engineering & Research Team (PLXsert), a new cybersecurity threat advisory. The... Read more
KMI MIDI K-Board Great Gift for Amateur &...
The K-Board is a MIDI Nano keyboard for music creation for iPad, Android, And computers; the easiest way to make music with iPads & Android tablets, and Mac, Windows, or Linux computers. Ultra-... Read more
Amazon offers 15-inch 2.2GHz Retina MacBook P...
 Amazon.com has the 15″ 2.2GHz Retina MacBook Pro on sale for $1699 including free shipping. Their price is $300 off MSRP. Stock is limited, so act now if you’re interested. Read more
Holiday sales continue: MacBook Pros for up t...
 B&H Photo has new MacBook Pros on sale for up to $300 off MSRP as part of their Holiday pricing. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1699... Read more
Holiday sale: Mac minis available for up to $...
 B&H Photo has new 2014 Mac minis on sale for up to $80 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 1.4GHz Mac mini: $459 $40 off MSRP - 2.6GHz Mac mini: $629 $70 off... Read more
Google Search App For iOS Gets A Major Makeov...
Google has given iOS users an early Christmas present with a substantial update of it’s not-very-often-upgraded Google Search app. Google Search has been my go-to tool for Web searches since it was... Read more
ShopKeep Apple Pay And Chip Card Reader Avail...
ShopKeep, a cloud-based technology provider to more than 10,000 small business owners to manage retail shops and restaurants with iPads, has released its new Apple Pay and chip card reader. This... Read more
Holiday sale! 27-inch 5K iMac for $2299, save...
 B&H Photo has the 27″ 3.5GHz 5K iMac in stock today and on sale for $2299 including free shipping plus NY sales tax only. Their price is $200 off MSRP, and it’s the lowest price available for... Read more

Jobs Board

Project Manager, *Apple* Financial Services...
**Job Summary** Apple Financial Services (AFS) offers consumers, businesses and educational institutions ways to finance Apple purchases. We work with national and Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.