FreeBASIC

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FreeBASIC
The FreeBASIC Logo
FreeBasic help.png
Paradigm(s) Procedural, object-oriented
Designed by Andre Victor[1]
Developer The FreeBASIC Development Team
Appeared in 2004
Stable release 1.00.0 / September 14, 2014 (2014-09-14)
Typing discipline Static
Influenced by QuickBASIC, C
OS DOS, FreeBSD, Linux, Microsoft Windows
License GNU GPL, Standard libraries licensed under the GNU LGPL
Website www.freebasic.net

FreeBASIC is a free/open source (GPL) BASIC compiler[2] for Microsoft Windows, protected-mode DOS (DOS extender), Linux, FreeBSD and Xbox. The Xbox version is no longer maintained.[3]

According to its official website,[4] FreeBASIC provides syntax compatibility with programs originally written in QuickBASIC. Unlike QuickBASIC, however, FreeBASIC is a compiler only and users must manually download, install and configure their IDE of choice.[5] IDEs specifically catered to FreeBASIC include FBide and FbEdit.

Compiler features[edit]

On its backend, FreeBASIC makes use of GNU binutils in order to produce console and GUI applications. FreeBASIC supports the linking and creation of C static and dynamic libraries and has limited support for C++ libraries. As a result, code compiled in FreeBASIC can be reused in most native development environments.

C style preprocessing, including multiline macros, conditional compiling and file inclusion, is supported. The preprocessor also has access to symbol information and compiler settings, such as the language dialect.

Syntax[edit]

Initially, FreeBASIC emulated QBASIC syntax as closely as possible. However, as the language evolved, breaking away from this was necessary. As a result, FreeBASIC now offers several language dialects.[6] New features include support for types as objects, operator overloading, function overloading, namespaces and others.[7]

End-of-line characters indicate the termination of programming statements. Multiple statements may be written on a single line by separating each statement with a colon.

FreeBASIC supports block commenting as well as end of line remarks. Full line comments are made with an apostrophe ', while blocks of commented code begin with /' and end with '/.

FreeBASIC is not case sensitive.

Graphics library[edit]

FreeBASIC provides built-in, QuickBASIC compatible graphics support through FBgfx, which is automatically included into programs that make a call to the SCREEN command. Its backend defaults to OpenGL on GNU/Linux and DirectX on Microsoft Windows. This abstraction makes FBgfx graphics code cross-platform compatible. However, FBgfx is not hardware accelerated.

Users familiar with external graphics utilities such as OpenGL or the Windows API can use them without interfering with the built-in graphics library.

Language dialects[edit]

As FreeBASIC has evolved, changes have been made which required breaking older-styled syntax. In order to continue supporting programs written using the older syntax, FreeBASIC now supports the following dialects:

  • The default dialect (-lang fb as a command-line argument) supports all new compiler features and disallows archaic syntax.
  • The FB-lite dialect (-lang fblite) permits use of most new, non-object-oriented features in addition to older-style programming. Implicit variables, suffixes, GOSUB / RETURN, numeric labels and other features are allowed in this dialect.
  • The QB dialect (-lang qb) attempts to replicate QuickBASIC behavior and is able to compile many QuickBASIC programs without modification.

Example code[edit]

Standard programs, such as the hello, world program are done just as they were in QuickBASIC.

Print "Hello World"
 
sleep:end 'Comment, prevents the program window from closing instantly

FreeBASIC adds to this with support for object-oriented features such as methods, constructors, dynamic memory allocation, properties and temporary allocation.

Type Vector
    Private:
        x As Integer
        y As Integer
    Public:
        Declare Constructor (nX As Integer = 0, nY As Integer = 0)
        Declare Property getX As Integer
        Declare Property getY As Integer
End Type
 
Constructor Vector (nX As Integer, nY As Integer)
    x = nX
    y = nY
End Constructor
 
Property Vector.getX As Integer
    Return x
End Property
 
Property Vector.getY As Integer
    Return y
End Property
 
Dim As Vector Ptr player = New Vector()
 
*player = Type<Vector>(100, 100)
Print player->getX
Print player->getY
 
Delete player
 
Sleep 'Prevents the program window from closing instantly

References[edit]

  1. ^ "FreeBASIC about page". FreeBASIC compiler. Retrieved 5 February 2012. 
  2. ^ Lee Seats. "FreeBASIC the Successor to QuickBASIC". About.com. Retrieved 2008-08-17. 
  3. ^ FBWiki : FaqPgxbox
  4. ^ FreeBASIC Programming Language: Official Website
  5. ^ "FreeBASIC official website downloads page". FreeBASIC compiler. Retrieved 5 February 2012. 
  6. ^ "FreeBASIC dialects". coderJeff's home page. Retrieved 5 February 2012. 
  7. ^ "Differences between QBASIC and FreeBASIC". FreeBASIC.net documentation. Retrieved 5 February 2012. 

External links[edit]

IDEs