Editing PureBasic (section)

== Programming language ==

=== Characteristics ===
PureBasic is a native cross platform 32 bit and 64 bit BASIC compiler. Currently supported systems are Windows, Linux, macOS. The AmigaOS version is legacy and open-source. The compiler produces native executables and the syntax of PureBasic is simple and straightforward, comparable to plain C without the brackets and with native unicode string handling and a large library of built-in support functions.<ref name="PureBasic home page">[http://www.purebasic.com/index.php PureBasic home page]</ref> It can compile console applications,<ref name="PureBasic - Console">[http://www.purebasic.com/documentation/console/index.html PureBasic - Console]</ref> GUI applications,<ref name="PureBasic - Gadget">[http://www.purebasic.com/documentation/gadget/index.html PureBasic - Gadget]</ref> and DLL files.<ref name="Building a DLL">[http://www.purebasic.com/documentation/reference/dll.html Building a DLL]</ref>

=== Hello World example ===
The following single line of PureBasic code will create a standalone x86 executable (4.5 KiB (4,608 bytes) on Windows version) that displays a message box with the text "[["Hello, World!" program|Hello World]]".
<syntaxhighlight lang="blitzbasic">
 MessageRequester("Message Box", "Hello World")</syntaxhighlight>

And the following variant of the same code, which instead uses an inline [[Windows API]] call with no need for declarations or other external references, will create an even smaller 2.0 KiB (2,048 bytes) standalone x86 executable for Windows.
<syntaxhighlight lang="blitzbasic">
 MessageBox_(0, "Hello World", "Message Box", 0)</syntaxhighlight>

The following is a console version of the Hello World example.
<syntaxhighlight lang="blitzbasic">
 OpenConsole()          ; Open a console window. 
 Print("Hello, World!")
 Delay(5000)            ; Pause for 5 seconds</syntaxhighlight>

=== Procedural programming ===
PureBasic is a "Second generation BASIC" language, with structured conditionals and loops, and procedure-oriented programming supported. The user is not required to use procedures, so a programmer may opt for a coding style which includes {{mono|Goto, Gosub Label}}, and {{mono|Return}}.

Below is a sample procedure for sorting an array, although SortArray is now a built-in function of PureBasic.
<syntaxhighlight lang="blitzbasic" line highlight="1,15">
 Procedure bubbleSort(Array a(1))
   Protected i, itemCount, hasChanged
  
   itemCount = ArraySize(a())
   Repeat
     hasChanged = #False
     itemCount - 1
     For i = 0 To itemCount
       If a(i) > a(i + 1)
         Swap a(i), a(i + 1)
         hasChanged = #True
       EndIf 
     Next  
   Until hasChanged = #False
 EndProcedure</syntaxhighlight>

Below is a sample program that displays a sizeable text editor with two menu items.
<syntaxhighlight lang="blitzbasic">
;Create Window:
OpenWindow(0, #PB_Ignore, #PB_Ignore, 800, 600, "Simple Text Editor", #PB_Window_SystemMenu | #PB_Window_MinimizeGadget | #PB_Window_MaximizeGadget | #PB_Window_SizeGadget)

;Add 2 menus:
CreateMenu(0, WindowID(0))
MenuItem(1, "&OK")
MenuItem(2, "&Cancel")

;Add Editor:
EditorGadget(0, 0, 0, 0, 0)
SetGadgetFont(0, LoadFont(0, "Courier New", 10))

;Process window messages until closed:
Repeat
    Select WaitWindowEvent()
    Case #PB_Event_Menu
        Select EventMenu()
        Case 1: MessageRequester("OK clicked directly or with '&' mnemonic.", GetGadgetText(0))
        Case 2: Break
        EndSelect
    Case #PB_Event_SizeWindow: ResizeGadget(0, 0, 0, WindowWidth(0, #PB_Window_InnerCoordinate), WindowHeight(0, #PB_Window_InnerCoordinate))
    Case #PB_Event_CloseWindow: Break
    EndSelect
ForEver
</syntaxhighlight>
PureBasic does not escape double quotes in strings so these must be concatenated with {{mono|Chr(34)}}.

=== Object-oriented programming ===
Fred, the developer of PureBasic, has stated that PureBasic will never be [[Object-oriented programming|object oriented]].<ref name="PureBasic won't be object oriented">[http://www.purebasic.fr/english/viewtopic.php?p=403070#p403070 PureBasic won't be object oriented]</ref> However, numerous users have created object oriented support systems.<ref name="PureBasic Forum: PureObject - PureBasic OOP support">[http://www.purebasic.fr/english/viewtopic.php?t=30236 PureObject: PureBasic OOP support]</ref><ref name="PureBasic Forum: OOP tutorial added to the nxSoftware site!">[http://www.purebasic.fr/english/viewtopic.php?t=36255 OOP tutorial]</ref><ref name="PureBasic Forum: Another OOP PreCompiler">[http://www.purebasic.fr/english/viewtopic.php?t=30774 Another OOP PreCompiler]</ref>

=== Data types ===
Variable data type specified when you first use it (and optionally - in the future), and is separated from the name of the point. There is a set of basic types - {{mono|.f, .d}} (float and double numbers), {{mono|.b, .c, .w, .l, .q}} (integers - from single-byte and 8-byte), {{mono|.s}} - strings.
{| class="wikitable"
|-
! Type !! Suffix !! Memory usage !! Numerical range
|-
| Byte || {{mono|b}} || 1 byte (8 bits) || −128 ... +127
|-
| Ascii || {{mono|a}} || 1 byte (8 bits) || 0 ... +255
|-
| Character || {{mono|c}} || 1 byte (8 bits) (ascii) || 0 ... +255
|-
| Word || {{mono|w}} || 2 bytes (16 bits) || −32768 ... +32767
|-
| Unicode || {{mono|u}} || 2 bytes (16 bits) || 0 ... +65535
|-
| Character || {{mono|c}} || 2 bytes (16 bits) (unicode) || 0 ... +65535
|-
| Long || {{mono|l}} || 4 bytes (32 bits) || −2147483648 ... +2147483647
|-
| Integer || {{mono|i}} || 4 bytes (32 bits) x86 || −2147483648 ... +2147483647
|-
| Float || {{mono|f}} || 4 bytes (32 bits) || Depending on the ratio of the decimal number.
|-
| Integer || {{mono|i}} || 8 bytes (64 bits) x64 || −9223372036854775808 ... +9223372036854775807
|-
| Quad || {{mono|q}} || 8 bytes (64 bits) || −9223372036854775808 ... +9223372036854775807
|-
| Double || {{mono|d}} || 8 bytes (64 bits) || Depending on the ratio of the decimal number.
|-
| String || {{mono|s}} || (String length + 1) * [[sizeof|SizeOf]](Character) || No limit.
|-
| Fixed String || {{mono|s{length}}} || (String length) * SizeOf(Character) || No limit.
|}

* {{mono|Len(String)}} used to count the length of a string will not exceed the first [[null character]] ({{mono|Chr(0)}}).

In addition to basic types, the user can define the type of construction via
<syntaxhighlight lang="text">
Structure type_name
   field_name.type ; Single field. Perhaps the structures attachment.
   field_name[count].type ; Static arrays.
   ; ... 
   ; Optional construction StructureUnion .. EndStructureUnion allows you
   ; to combine multiple fields into one area of memory
   ; that is sometimes required for the conversion types.
   StructureUnion
      type_name.type
      ; ... 
   EndStructureUnion 
EndStructure
</syntaxhighlight>

Variables can be single (actually, standard variables), [[dynamic array]] (declared using the {{code|lang=blitzbasic|Dim var_name.type_name (size1, size2, ... )}}, a [[linked list]] ({{code|lang=blitzbasic|List() var_name.type_name}}), an [[associative array]] (in new versions of language) ({{code|Map var_name.type_name()}})