freeBASIC

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Not to be confused with Free Basics.
FreeBASIC
Fblogo.gif
FreeBasic help.png
Paradigm Procedural, object-oriented
Designed by Andre Victor[1]
Developer The FreeBASIC Development Team
First appeared 2004; 12 years ago (2004)
Stable release
1.05.0 / January 31, 2016; 10 months ago (2016-01-31)
Typing discipline Static
OS DOS, FreeBSD, Linux, Microsoft Windows
License GNU GPLv2+, Standard libraries licensed under the GNU LGPLv2+
Website www.freebasic.net
Influenced by
QuickBASIC, C

FreeBASIC is a multiplatform, 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 The Xbox version is no longer maintained.[3]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 Web site,[4] FreeBASIC provides syntax compatibility with programs originally written in Microsoft QuickBASIC (QB). Unlike QuickBASIC, however, FreeBASIC is a command line only compiler, unless users manually install an external integrated development environment (IDE) of their choice.[5] IDEs specifically made for FreeBASIC include FBide and FbEdit.

Compiler features[edit]

On its back end, FreeBASIC makes use of GNU Binutils in order to produce console and graphical user interface 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 Microsoft QuickBASIC syntax as closely as possible. Beyond that, the language has continued its evolution. As a result, FreeBASIC combines several language dialects for maximum level of compatibility with QuickBASIC and full access to modern features.[6] New features include support for concepts such as objects, operator overloading, function overloading, namespaces and others.[7]

Newline characters indicate the termination of programming statements. A programming statement can be distributed on multiple consecutive lines by using the underscore line continuation char (_), whereas multiple statements may be written on a single line by separating each statement with a colon (:).

Block comments, as well as end-of-line remarks are supported. 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 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 that 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

In both cases, the language is well suited for learning purposes.

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 Web site
  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 from QB". freeBASIC.net documentation. Retrieved 5 February 2012. 

External links[edit]

IDEs