ADUG 17 Feb 2020

Lazarus and Free Pascal

What are they?
--------------
Free Pascal is the compiler and linker
  multi platform (Windows, Mac OSX, Linux, etc)
  multi architecture (32 and 64 bit)
  
Lazarus 
  is the IDE
  and contains a visual component library (the "LCL" = VCL)
  forms have a .lfm extension
  project files have .lpi and .lps extensions

How to get FPC and Lazarus?
---------------------------
You can download both from the SubVersion repositories on Sourceforge, but a much easier route is to use:

FPCupdeluxe
  download and install it from http://newpascal.org/download (it's a Windows program)
  select trunk for both Lazarus and FPC and let it download and build Lazarus
  you can add Mormot, Python and other modules easily at any later time
  and cross compilers (see later)

Lazarus IDE
  include the AnchorDockingDsgn package (Packages/Install.Uninstall Packages...) so you have a more Delphi compatible docked window layout
  (read about docked layouts at http://newpascal.org/docked.html
  macros, key binding, edit and save to Project or IDE
  some keyboard shortcuts are different to Delphi (but many are the same)
  code completion is a little different (see https://wiki.freepascal.org/Lazarus_IDE_Tools#Code_Completion)
  
Windows Demo 
------------
"Proofreader" app
  Delphi screenshots of original app which used
    TRichview
  Lazarus/FPC Windows 32 bit app
    KMemo as replacement for TRichView (Google KControls)
 
Language
  include {$mode delphi} at the top of your units tomake the FP language more Delphi compatible, especially:
  
Generics
  TList<record> or TList<class>
  TDictionary
  see http://newpascal.org/assets/modern_pascal_introduction.html#_generics  for more useful info

Unicode
  € etc
  make sure your files are UTF-8 if you want to load them with LoadFromFile using the default encoding
  see https://wiki.freepascal.org/Character_and_string_types for more info on other available string types
  
Debugging
  poorest feature (due to cross platform considerations) compared to Delphi
  but still very useable; 
  Tooltip drill down of structured data is lacking
  Has call stack, breakpoints, watches, inspector, eval and modify windows
  can have a separate debug window layout from development layout (Tools/Manage Desktops)

Cross compiler demo
-------------------
  Linux 64 bit
  use FPCUpdeluxe to install a cross compiler (i86-x64 and Linux in my case). Select a cross compiler on the Cross tab.
  Choose your new target and compile for eg Linux under Windows
  copy to your target platform eg Ubuntu linux and run.  
  It may not always be as easy as I demonstrated; but I was very impressed!
  
  The option to set the target platform is documented here:
  https://wiki.lazarus.freepascal.org/IDE_Window:_Compiler_Options#Config_and_Target

More reading
------------  
Components (LCL)
  TStringGrid has enhancements such as alt row colouring, check boxes, sorting. see https://wiki.freepascal.org/TStringGrid
  TAChart. very complete equivalent of TChart. see https://wiki.freepascal.org/TAChart

Help, tutorials, wiki and 
  From the IDE open any of Tools/Example Projects
  and https://wiki.freepascal.org/Lazarus_Application_Gallery
  
  read and search https://wiki.lazarus.freepascal.org/ for lots of great help
  
  The newpascal site has a great pascal tutorial at http://newpascal.org/assets/modern_pascal_introduction.html

Richard King