BlitzMax/Modules/BASIC/BlitzMax runtime

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The Blitz runtime module provides low level functionality required by BlitzMax applications when they are running. This includes things like memory management, exception handling and string and array operations.

Much of the functionality provided by this module is hidden from application programmers, but is instead used 'behind the scenes' by the compiler. However, there are some very useful commands for debugging, memory management and simple standard IO.

Contents

Globals[edit]

AppDir[edit]

Global AppDir$="bbAppDir"

Description: Application directory

Information: The AppDir global variable contains the fully qualified directory of the currently executing application. An application's initial current directory is also set to AppDir when an application starts.

Example:

' appdir.bmx
' requests the user to select a file from the application's directory

Print "Application Directory="+AppDir$

file$=RequestFile("Select File to Open","",False,AppDir$)

Print "file selected was :"+file

AppFile[edit]

Global AppFile$="bbAppFile"

Description: Application file name

Information: The AppFile global variable contains the fully qualified file name of the currently executing application.

Example:

' appfile.bmx

Print "This program's executable is located at "+AppFile$

AppTitle[edit]

Global AppTitle$="bbAppTitle"

Description: Application title

Information: The AppTitle global variable is used by various commands when a default application title is required - for example, when opening simple windows or requesters. Initially, AppTitle is set the value "BlitzMax Application". However, you may change AppTitle at any time with a simple assignment.

AppArgs[edit]

Global AppArgs$[]="bbAppArgs"

Description: Arguments passed to the application at startup

Information: The AppArgs global array contains the command line parameters sent to an application when it was started. The first element of AppArgs always contains the name of the application. However, the format of the name may change depending on how the application was launched. Use AppDir or AppFile for consistent information about the applications name or directory.

Example:

' appargs.bmx
' print the command line arguments passed to the program at runtime

Print "Number of arguments = "+AppArgs.length

For a$=EachIn AppArgs
Print a$
Next

LaunchDir[edit]

Global LaunchDir$="bbLaunchDir"

Description: Directory from which application was launched

Information: The LaunchDir global variable contains the current directory at the time the application was launched. This is mostly of use to command line tools which may need to access the 'shell' current directory as opposed to the application directory.

Example:

' launchdir.bmx

Print "This program was launched from "+LaunchDir$

Functions[edit]

RuntimeError[edit]

Function RuntimeError( message$ )

Description: Generate a runtime error

Information: Throws a TRuntimeException.

Example:

' runtimeerror.bmx

If a=0 RuntimeError "This program has failed badly."

DebugStop[edit]

Function DebugStop()

Description: Stop program execution and enter debugger

Information: If there is no debugger present, this command is ignored.

DebugLog[edit]

Function DebugLog( message$ )

Description: Write a string to debug log

Information: If there is no debugger present, this command is ignored.

Comment: note that, unlike Assert, DebugLog will get compiled regardless of the compilation mode - just that nothing is printed in Release mode.

OnEnd[edit]

Function OnEnd( fun() )

Description: Add a function to be called when the program ends

Information: OnEnd allows you to specify a function to be called when the program ends. OnEnd functions are called in the reverse order to that in which they were added.

Example:

' onend.bmx

Function cleanup()
Print "cleaning up"
End Function

OnEnd cleanup
Print "program running"
End     'the cleanup function will be called at this time

ReadStdin[edit]

Function ReadStdin$()

Description: Read a string from stdin

Returns: A string read from stdin. The newline terminator, if any, is included in the returned string.

WriteStdout[edit]

Function WriteStdout( str$ )

Description: Write a string to stdout

Information: Writes str to stdout and flushes stdout.

WriteStderr[edit]

Function WriteStderr( str$ )

Description: Write a string to stderr

Information: Writes str to stderr and flushes stderr.

Delay[edit]

Function Delay( millis )

Description: Wait for a given number of milliseconds

Information: Delay suspends program execution for at least millis milliseconds. A millisecond is one thousandth of a second.

MilliSecs[edit]

Function MilliSecs()

Description: Get millisecond counter

Returns: Milliseconds since computer turned on.

Information: MilliSecs returns the number of milliseconds elapsed since the computer was turned on. A millisecond is one thousandth of a second.

MemAlloc[edit]

Function MemAlloc:Byte Ptr( size )

Description: Allocate memory

Returns: A new block of memory size bytes long

MemFree[edit]

Function MemFree( mem:Byte Ptr )

Description: Free allocated memory

Information: The memory specified by mem must have been previously allocated by MemAlloc or MemExtend.

MemExtend[edit]

Function MemExtend:Byte Ptr( mem:Byte Ptr,size,new_size )

Description: Extend a block of memory

Returns: A new block of memory new_size bytes long

Information: An existing block of memory specified by mem and size is copied into a new block of memory new_size bytes long. The existing block is released and the new block is returned.

MemClear[edit]

Function MemClear( mem:Byte Ptr,size )

Description: Clear a block of memory to 0

MemCopy[edit]

Function MemCopy( dst:Byte Ptr,src:Byte Ptr,size )

Description: Copy a non-overlapping block of memory

MemMove[edit]

Function MemMove( dst:Byte Ptr,src:Byte Ptr,size )

Description: Copy a potentially overlapping block of memory

GCSetMode[edit]

Function GCSetMode( mode )

Description: Set garbage collector mode

Information: mode can be one of the following:
1 : automatic GC - memory will be automatically garbage collected
2 : manual GC - no memory will be collected until a call to GCCollect is made
The default GC mode is automatic GC.

GCSuspend[edit]

Function GCSuspend()

Description: Suspend garbage collector

Information: GCSuspend temporarily suspends the garbage collector. No garbage collection will be performed following a call to GCSuspend.
Use GCResume to resume the garbage collector. Note that GCSuspend and GCResume 'nest', meaning that each call to GCSuspend must be matched by a call to GCResume.

GCResume[edit]

Function GCResume()

Description: Resume garbage collector

Information: GCResume resumes garbage collection following a call to GCSuspend.
See GCSuspend for more details.

GCCollect[edit]

Function GCCollect()

Description: Run garbage collector

Returns: The amount of memory, in bytes, collected.

Information: This function will have no effect if the garbage collector has been suspended due to GCSuspend.

GCMemAlloced[edit]

Function GCMemAlloced()

Description: Memory allocated by application

Returns: The amount of memory, in bytes, currently allocated by the application

Information: This function only returns 'managed memory'. This includes all objects, strings and arrays in use by the application.

GCEnter[edit]

Function GCEnter()

Description: Private: do not use

GCLeave[edit]

Function GCLeave()

Description: Private: do not use

HandleFromObject[edit]

Function HandleFromObject( obj:Object )

Description: Convert object to integer handle

Returns: An integer object handle

Information: After converting an object to an integer handle, you must later release it using the Release command.

HandleToObject[edit]

Function HandleToObject:Object( handle )

Description: Convert integer handle to object

Returns: The object associated with the integer handle

Example:

' handlefromobject.bmx

Type MyType
        Field x:Int=100
End Type

Local obj:MyType=New MyType
Local handle:Int=HandleFromObject(obj)
Print "handle = "+handle

Local obj2:MyType=MyType(HandleToObject(handle))
If obj=obj2 Then Print "obj = obj2"
Print "x = "+obj2.x

Release handle

Keywords[edit]

Strict[edit]

Description: Set strict mode

Information: See BASIC Compatibility for more information on Strict mode programming.

Comment: In Strict mode automatic data typing is permitted. The default data type is Int.

Example:

Rem
Strict advises the BlitzMax compiler to report as errors all auto defined variables.
End Rem

Strict

local a=10

b=20    'compiler error, strict mode means variables must be declared b4 use

SuperStrict[edit]

Description: Set SuperStrict mode

Comment: In SuperStrict mode data types must always be specified.

End[edit]

Description: End program execution

Example:

Rem
The End command causes a program to exit immediately.
End Rem

Print "Hello!"
End
Print "This line will never be printed as the program has already been ended."

Rem[edit]

Description: Begin a remark block

Example:

Rem

My Rem Example
First created 9th August, 2004

(C)2050 Blitz Intergalactic Software Corporation

End Rem

Print "This program has no useful function"

Rem

Remarks are useful for making your program easily readable.
You can leave details explaining the function of your program
in a remarks section so that you and any other programmers
that work with your code can more easily understand the workings
of your program

End Rem

Print "Sorry."
End

EndRem[edit]

Description: End a remark block

Example:

Rem
All code between Rem and EndRem is ignored by the BlitzMax compiler.
Print "hello"
End Rem

Print "goodbye"

True[edit]

Description: Constant integer of value 1

Example:

Rem
True is a Constant Integer assigned the value 1.
End Rem

Print "True="+True

If True
        Print "This line will always be executed"
EndIf

If Not True
        Print "This line will never be executed"
EndIf

False[edit]

Description: Constant integer of value 0

Example:

Rem
False is a Constant Integer assigned the value 0.
End Rem

Print "False="+False

If False
        Print "This code will never be executed"
Endif

Pi[edit]

Description: Constant Pi value: 3.1415926535897932384626433832795

Example:

Rem
Pi is a Constant Double assigned the value 3.1415926535897932384626433832795
End Rem

Print "Pi="+Pi

Null[edit]

Description: Get Default Null value

Example:

Rem
Null is a BlitzMax Constant representing an empty Object reference.
End Rem

Type mytype
        Field   atypevariable
End Type

Global a:mytype

if a=null Print "a is uninitialized"
a=new mytype
if a<>null Print "a is initialized"

Byte[edit]

Description: Unsigned 8 bit integer Type

Example:

Rem
Byte is an unsigned 8 bit integer BlitzMax primitive type.
End Rem

Local a:Byte

a=512;Print "a="+a    'prints 0
a=-1;Print "a="+a     'prints 255

Short[edit]

Description: Unsigned 16 bit integer Type

Example:

Rem
Short is an unsigned 16 bit integer BlitzMax primitive type.
End Rem

Local a:Short

a=65536;Print "a="+a  'prints 0
a=-1;Print "a="+a     'prints 65535

Int[edit]

Description: Signed 32 bit integer Type

Example:

Rem
Int is a signed 32 bit integer BlitzMax primitive type.
End Rem

Local a:Int

' the following values all print 0 as BlitzMax "rounds to zero"
' when converting from floating point to integer

a=0.1;Print a
a=0.9;Print a
a=-0.1;Print a
a=-0.9;Print a

Long[edit]

Description: Signed 64 bit integer Type

Example:

Rem
Long is a signed 64 bit integer BlitzMax primitive type.
End Rem

Const MAXLONG:Long=$7fffffffffffffff:Long
Const MINLONG:Long=$8000000000000000:Long

Print "A long can have the maximum value of:"+MAXLONG
Print "A long can have the minimum value of:"+MINLONG

Float[edit]

Description: 32 bit Floating point Type

Example:

Rem
Float is a 32 bit floating point BlitzMax primitive type.
End Rem

Local a:Float

a=1

For i=1 To 8
        Print a
        a=a*0.1
Next

For i=1 To 8
        a=a*10
        Print a
Next

Double[edit]

Description: 64 bit floating point Type

Example:

Rem
Double is a 64 bit floating point BlitzMax primitive type.
End Rem

Local speedoflight:Double
Local distance:Double
Local seconds:Double

speedoflight=299792458:Double   'meters per second
distance=149597890000:Double    'average distance in meters from earth sun

seconds=distance/speedoflight

Print "Number of seconds for light to travel from earth to sun="+seconds

String[edit]

Description: String Type

Example:

Rem
String is a BlitzMax container type containing a sequence of unicode characters.
End Rem

quote:String=Chr(34)
Print quote+"Hello World!"+quote

Object[edit]

Description: Object Type

Example:

Rem
Object is the base class of all BlitzMax types.

The following function attempts to cast from any object to
the custom type TImage and returns true if the given object
is an instance of TImage or an instance of a &Type derived
from TImage.
End Rem

Function IsImage(obj:Object)
        If TImage(obj) return True
        Return False
End Function

Var[edit]

Description: Composite Type specifier for 'by reference' types

Example:

Rem
Var is a composite type containing a reference to a variable of the 
specified Type.
End Rem

' the following illustrates parsing function parameters by reference

Function ReturnMultiplevalues(a Var,b Var,c Var)
        a=10
        b=20
        c=30
        Return
End Function

Local x,y,z

ReturnMultipleValues(x,y,z)

Print "x="+x  '10
Print "y="+y  '20
Print "z="+z  '30

Ptr[edit]

Description: Composite Type specifier for pointer types

Example:

Rem
Ptr is a composite type containing a pointer to a variable of the specified Type.
End Rem

' the following illustrates the use of traditional c style pointers

Local c[]=[1,2,3,4]
Local p:Int Ptr

p=c
Print "pointer 'p' points to:"+p[0]   '1

p:+1
Print "pointer 'p' points to:"+p[0]   '2

p:+1
Print "pointer 'p' points to:"+p[0]   '3

p:+1
Print "pointer 'p' points to:"+p[0]   '4

If[edit]

Description: Begin a conditional block.

Example:

Rem
If begins a conditional block.
End Rem

If 3<5 Print "3<5"      'single line if

If 5<7                       'if block
        Print "5<7"
EndIf

Then[edit]

Description: Optional separator between the condition and associated code in an If statement.

Example:

Rem
Then is an optional separator between the condition and the block of code following an If statement.
End Rem

If 3<5 Then Print "3<5"

Else[edit]

Description: Else provides the ability for an If Then construct to execute a second block of code when the If condition is False.

Example:

Rem
Else provides the ability for an If Then construct to execute a second block of code when the If condition is false.
End Rem

i=3

If i<5 Print "i<5" Else Print "i>=5"       'single line If Else

If i<5                                       'block style If Else
        Print "i<5"
Else
        Print "i>=5"
EndIf

ElseIf[edit]

Description: ElseIf provides the ability to test and execute a section of code if the initial condition failed.

Example:

Rem
ElseIf provides the ability to test and execute a section of code if the initial condition failed.
End Rem

age=Int( Input("How old Are You?") )

If age<13
        Print "You are young"
ElseIf age<20
        Print "You are a teen!"
Else
        Print "You are neither young nor a teen"
EndIf

EndIf[edit]

Description: Marks the end of an If Then block.

Example:

Rem
EndIf marks the end of an If Then block.
End Rem

i=5

If i<10
        Print "i<10"
EndIf

For[edit]

Description: Marks the start of a loop that uses an iterator to execute a section of code repeatedly.

Example:

Rem
For marks the start of a loop that uses an iterator to execute a section of code repeatedly.
End Rem

' print 5 times table

For i=1 to 12
        Print "5*"+i+"="+5*i
Next

To[edit]

Description: Followed by a constant which is used to calculate when to exit a For..Next loop.

Example:

Rem
Followed by a constant which is used to calculate when to exit a For..Next loop.
End Rem

For i=1 To 5
        Print i
Next

Step[edit]

Description: Specifies an optional constant that is used to increment the For iterator.

Example:

Rem
Specifies an optional constant that is used to increment the For iterator.
End Rem

' count backwards from 10 to 0

For i=10 to 0 step -1
        Print i
Next

Next[edit]

Description: End a For block

Example:

Rem
Marks the end of a For section.
End Rem

For i=1 To 5;Print i;Next

EachIn[edit]

Description: Iterate through an array or collection

Example:

Rem
Specifies a BlitzMax collection type whose values are assigned sequentially to the For iterator.
End Rem

Local a[]=[0,5,12,13,20]

For b=EachIn a
        Print b
Next

While[edit]

Description: Execute a block of code while a condition is True

Example:

Rem
While executes the following section of code repeatedly while a given condition is true.
End Rem

Graphics 640,480
While Not KeyHit(KEY_ESCAPE)    'loop until escape key is pressed
        Cls
        For i=1 to 200
                DrawLine rnd(640),rnd(480),rnd(640),rnd(480)
        Next
        Flip
Wend

Wend[edit]

Description: End a While block

Example:

Rem
Wend marks the end of a While section.
End Rem

While i<5
        Print i
        i:+1
Wend

EndWhile[edit]

Description: End a While block

Repeat[edit]

Description: Execute a block of code until a termination condition is met, or forever

Example:

Rem
Repeat executes the following section of code until a terminating condition is true.
End Rem

Repeat
        Print i
        i:+1
Until i=5

Until[edit]

Description: Conditionally continue a Repeat block

Example:

Rem
Until marks the end of a Repeat block and is followed by a terminating condition.
End Rem

i=2
Repeat
        Print i
        i:*2
Until i>1000000

Forever[edit]

Description: Continue a Repeat block forever

Example:

Rem
Forever is an alternate ending to a Repeat block that will cause the loop to always repeat.
End Rem

Repeat
        Print i+" Ctrl-C to End!" 
        i:+1
Forever

Select[edit]

Description: Begin a Select block

Example:

Rem
Select begins a block featuring a sequence of multiple comparisons with a single value.
End Rem

a=Int( Input("Enter Your Country Code ") )

Select a
        Case 1
                Print "You are from America"
        Case 44
                Print "You are from the United Kingdom"
        Case 62
                Print "You are from Australia"
        Case 64
                Print "You are from New Zealand"
        Default
                Print "I cannot tell which country you are from"
End Select

EndSelect[edit]

Description: End a Select block

Example:

Rem
EndSelect marks the end of a Select block.
End Rem

SeedRnd MilliSecs()

a=Rand(5)

Select a
        Case 1 Print "one"
        Case 2 Print "two"
        Case 3 Print "three"
        Case 4 Print "four"
        Case 5 Print "five"
        Default Print "Program Error"
End Select

Case[edit]

Description: Conditional code inside a Select block

Example:

' case.bmx

' Case performs a comparison with the preceeding value(s) and that
' listed in the enclosing Select statement:

a=Int( Input("Enter a number between 1 and 5 ") )

Select a
        Case 1 Print "You think small"
        Case 2 Print "You are even tempered"
        Case 3,4 Print "You are middle of the road"   
        Case 5 Print "You think big"
        Default Print "You are unable to follow instructions"
End Select              

Default[edit]

Description: Default code inside a Select block

Example:

Rem
Default is used in a Select block to mark a code section that is executed if all prior Case statements fail.
End Rem

a$=Input("What is your favorite color?")
a$=Lower(a$)    'make sure the answer is lower case

Select a$
        Case "yellow" Print "You a bright and breezy"
        Case "blue" Print "You are a typical boy"
        Case "pink" Print "You are a typical girl"
        Default Print "You are quite unique!"
End Select

Exit[edit]

Description: Exit enclosing loop

Example:

Rem
Exit causes program flow to exit the enclosing While, Repeat or For loop.
End Rem

Repeat
        Print n
        n:+1
        If n=5 Exit
Forever

Continue[edit]

Description: Continue execution of enclosing loop

Example:

Rem
Continue causes program flow to return to the start of the enclosing While, Repeat or For program loop
End Rem

For i=1 To 20
        If i Mod 2 Continue
        Print i
Next

Const[edit]

Description: Declare a constant

Example:

Rem
Const defines the preceeding variable declaration as constant.
End Rem

Const ON=True
Const OFF=False

Const TWOPI#=2*Pi

Print TWOPI

Local[edit]

Description: Declare a Local variable

Example:

Rem
Local defines a variable as local to the Method or Function it is defined meaning it is automatically released when the function returns.
End Rem

Function TestLocal()
        Local   a
        a=20
        Print "a="+a
        Return
End Function

TestLocal
Print "a="+a  'prints 0 or if in Strict mode is an error as a is only local to the TestLocal function

Global[edit]

Description: Declare a Global variable

Example:

Rem
Global defines a variable as Global allowing it be accessed from within Methods and Functions.
End Rem

Global a=20

Function TestGlobal()
        Print "a="+a
End Function

TestGlobal
Print "a="+a

Field[edit]

Description: Declare a Field variable

Example:

Rem
Field is used to declare the member variable(s) of a type.
End Rem

Type TVector
        Field   x,y,z
End Type

Local a:TVector=New TVector

a.x=10
a.y=20
a.z=30

Function[edit]

Description: Begin a Function declaration

Example:

Rem
Function marks the beginning of a BlitzMax function declaration.

When a function does not return a value the use of brackets when
calling the function is optional.
End Rem

Function NextArg(a$)
        Local   p
        p=Instr(a$,",")
        If p 
                NextArg a$[p..]
                Print a$[..p-1]
        Else
                Print a$
        EndIf
End Function

NextArg("one,two,three,four")

NextArg "22,25,20"    'look ma, no brackets

EndFunction[edit]

Description: End a Function declaration

Example:

Rem
Function marks the end of a BlitzMax function declaration.
End Rem

Function RandomName$()
        local a$[]=["Bob","Joe","Bill"]
        Return a[Rnd(Len a)]
End Function

For i=1 To 5
        Print RandomName$()
Next

Return[edit]

Description: Return from a Function

Example:

Rem
Return exits a BlitzMax function or method with an optional value.
The type of return value is dictated by the type of the function.
End Rem

Function CrossProduct#(x0#,y0#,z0#,x1#,y1#,z1#)
        Return x0*x1+y0*y1+z0*z1
End Function

Print "(0,1,2)x(2,3,4)="+CrossProduct(0,1,2,2,3,4)

Function LongRand:Long()
        Return (Rand($80000000,$7fffffff) Shl 32)|(Rand($80000000,$7fffffff))
End Function

Print "LongRand()="+LongRand()
Print "LongRand()="+LongRand()

Type[edit]

Description: Begin a user defined Type declaration

Example:

Rem
Type marks the beginning of a BlitzMax custom type.

Standard BlitzMax types use a preceeding "T" naming
convention to differentiate themselves from standard
BlitzMax variable names.
End Rem

Type TVector
        Field   x,y,z
End Type

Local a:TVector=New TVector

a.x=10
a.y=20
a.z=30

EndType[edit]

Description: End a user defined Type declaration

Example:

Rem
EndType marks the end of a BlitzMax custom type.
End Rem

Type TVector
        Field   x,y,z
End Type

Local a:TVector=New TVector

a.x=10
a.y=20
a.z=30

Extends[edit]

Description: Specify user defined Type supertype

Comment: The Type inherits a given base Type.

Example:

Rem
Extends is used in a BlitzMax Type declaration to derive the Type from a specified base class.
End Rem

Type TShape
        Field   xpos,ypos
        Method Draw() Abstract
End Type

Type TCircle Extends TShape
        Field   radius
        
        Function Create:TCircle(x,y,r)
                Local c:TCircle=New TCircle
                c.xpos=x;c.ypos=y;c.radius=r
                Return c
        End Function
        
        Method Draw()
                DrawOval xpos,ypos,radius,radius
        End Method
End Type

Type TRect Extends TShape
        Field   width,height
        
        Function Create:TRect(x,y,w,h)
                Local r:TRect=New TRect
                r.xpos=x;r.ypos=y;r.width=w;r.height=h
                Return r
        End Function
        
        Method Draw()
                DrawRect xpos,ypos,width,height
        End Method
End Type

Local   shapelist:TShape[4]
Local   shape:TShape

shapelist[0]=TCircle.Create(200,50,50)
shapelist[1]=TRect.Create(300,50,40,40)
shapelist[2]=TCircle.Create(400,50,50)
shapelist[3]=TRect.Create(200,180,250,20)

Graphics 640,480
While Not KeyHit(KEY_ESCAPE)
        Cls
        For shape=EachIn shapelist
                shape.draw
        Next
        Flip
Wend
End

Method[edit]

Description: Begin a Method declaration

Comment: Methods are instance-specific functions.

Example:

Rem
Method marks the beginning of a BlitzMax custom type member function.
End Rem

Type TPoint
        Field   x,y

        Method ToString$()
                Return x+","+y
        End Method
End Type

a:TPoint=New TPoint
Print a.ToString()

EndMethod[edit]

Description: End a Method declaration

Example:

Rem
EndMethod marks the end of a BlitzMax Method declaration.
End Rem

Type TPoint
        Field   x,y

        Method ToString$()
                Return x+","+y
        End Method
End Type

a:TPoint=New TPoint
Print a.ToString()

Abstract[edit]

Description: Denote a Type or Method as Abstract

Comment: The Type or Method must be extended (compilation will fail if it was not extended).

Example:

Rem
A BlitzMax type that contains Abstract methods becomes abstract itself.
Abstract types are used to define interfaces that extending types must 
implement before they can be used to create new instances.

In the following code TShape is an abstract type in that you can not
create a TShape but anything extending a TShape must implement a Draw()
method.
End Rem

Type TShape
        Field   xpos,ypos
        Method Draw() Abstract
End Type

Type TCircle Extends TShape
        Field   radius
        
        Function Create:TCircle(x,y,r)
                Local c:TCircle=New TCircle
                c.xpos=x;c.ypos=y;c.radius=r
                Return c
        End Function
        
        Method Draw()
                DrawOval xpos,ypos,radius,radius
        End Method
End Type

Type TRect Extends TShape
        Field   width,height
        
        Function Create:TRect(x,y,w,h)
                Local r:TRect=New TRect
                r.xpos=x;r.ypos=y;r.width=w;r.height=h
                Return r
        End Function
        
        Method Draw()
                DrawRect xpos,ypos,width,height
        End Method
End Type

Local   shapelist:TShape[4]
Local   shape:TShape

shapelist[0]=TCircle.Create(200,50,50)
shapelist[1]=TRect.Create(300,50,40,40)
shapelist[2]=TCircle.Create(400,50,50)
shapelist[3]=TRect.Create(200,180,250,20)

Graphics 640,480
While Not KeyHit(KEY_ESCAPE)
        Cls
        For shape=EachIn shapelist
                shape.draw
        Next
        Flip
Wend
End

Final[edit]

Description: Denote a Type or Method as Final

Comment: The Type or Method is not extendable.

Example:

Rem
Final stops methods from being redefined in super classes.
End Rem

Type T1
        Method ToString$() Final
                Return "T1"
        End Method
End Type

Type T2 Extends T1
        Method ToString$()      'compile time error "Final methods cannot be overridden"
                Return "T2"
        End Method
End Type

New[edit]

Description: Create an instance of a user defined Type

Example:

Rem
New creates a BlitzMax variable of the Type specified.
End Rem

Type MyType
        Field   a,b,c
End Type

Local t:MyType
t=New MyType
t.a=20

Print t.a

' if a new method is defined for the type it will also be called

Type MyClass
        Field   a,b,c
        Method New()
                Print "Constructor invoked!"
                a=10
        End Method
End Type

Local c:MyClass
c=New MyClass
Print c.a

Self[edit]

Description: Reference to this Method's Object instance

Comment: Allows an object access to its own instance (not needed in most cases).

Example:

Rem
Self is used in BlitzMax Methods to reference the invoking variable.
End Rem

Type MyClass
        Global  count   
        Field   id
        
        Method New()
                id=count
                count:+1
                ClassList.AddLast(Self) 'adds this new instance to a global list                
        End Method
End Type

Global ClassList:TList

classlist=New TList

Local c:MyClass

c=New MyClass
c=New MyClass
c=New MyClass

For c=EachIn ClassList
        Print c.id
Next

Super[edit]

Description: Reference to the Super Type Object instance

Comment: Allows an object access to its parent type (the type that it extends).

Example:

Rem
Super evaluates to Self cast to the method's immediate base class.
End Rem

Type TypeA
        Method Report()
                Print "TypeA reporting"
        End Method
End Type

Type TypeB Extends TypeA
        Method Report()
                Print "TypeB Reporting"
                Super.Report()
        End Method
End Type

b:TypeB=New TypeB
b.Report()

Delete[edit]

Description: Reserved for future expansion

Example:

Rem
Reserved for future expansions.
End Rem

Release[edit]

Description: Release an integer Object handle

Example:

Rem
Release removes the internal reference caused by creating an integer handle to a type.
End Rem

Type MyType
        Field bigmap[1024*1024]
End Type

GCCollect
Print GCMemAlloced()

a=New MyType
GCCollect
Print GCMemAlloced()

Release a
GCCollect
Print GCMemAlloced()

Public[edit]

Description: Public makes a Constant, Global variable or Function accessible from outside the current source file (Default)

Example:

Rem
Public makes a variable, function or method accessible from outside the current source file (default).
End Rem

Public

Global  Score,Lives,Health

Private

Global  posx,posy,posz

Private[edit]

Description: Private makes a Constant, Global variable or Function only accessible from within the current source file

Example:

Rem
Private makes a variable, function or method only accessible from within the 
current source file.
End Rem

Public

Global  Score,Lives,Health

Private

Global  posx,posy,posz

Extern[edit]

Description: Extern marks the beginning of an external list of Function declarations

Example:

Rem
Extern marks the beginning of an external list of function declarations.
End Rem

Extern 
        Function puts( str$z )
        Function my_puts( str$z )="puts"
End Extern

puts "Using clib's put string!"
my_puts "Also using clib's put string!"

EndExtern[edit]

Description: EndExtern marks the End of an Extern section

Example:

Rem
EndExtern marks the end of an Extern section.
End Rem

Extern 
        Function puts( str$z )
End Extern

puts "Using clib's put string!"

Module[edit]

Description: Declare Module scope and identifier

Information: See Modules for more information.

Example:

Rem
The Module keyword advises the BlitzMax program maker BMK to create a code 
module from the source file.
End Rem

Module PUB.Sequencer

ModuleInfo "Framework: Audio Sequencer for use with FreeAudio"
ModuleInfo "Copyright: Blitz Research Ltd"
ModuleInfo "Author: Simon Armstrong"
ModuleInfo "Version: 1.00"

ModuleInfo[edit]

Description: Define Module properties

Example:

Rem
ModuleInfo allows properties such as Author and Copyright to be included in a module file.
End Rem

Module PUB.Sequencer

ModuleInfo "Framework: Audio Sequencer for use with FreeAudio"
ModuleInfo "Copyright: Blitz Research Ltd"
ModuleInfo "Author: Simon Armstrong"
ModuleInfo "Version: 1.00"

Incbin[edit]

Description: Embed a data file

Example:

Rem
IncBin embeds an external data file in a BlitzMax program that can 
then be read using the "incbin::" device name.
End Rem

' code snippet from demos/firepaint/firepaint.bmx

Incbin "stars.png"

Local stars=LoadImage( "incbin::stars.png" )

IncbinPtr[edit]

Description: Get start address of embedded data file

Example:

Rem
IncBinPtr returns a byte pointer to the specified embedded binary file.
End Rem

Incbin "incbinptr.bmx"

Local p:Byte Ptr=IncbinPtr("incbinptr.bmx")
Local bytes=IncbinLen("incbinptr.bmx")

Local s$=String.FromBytes(p,bytes)

Print "StringFromBytes(p,bytes)="+s$

IncbinLen[edit]

Description: Get length of embedded data file

Example:

Rem
IncBinLen returns the size in bytes of the specified embedded binary file.
End Rem

Incbin "incbinlen.bmx"

Local p:Byte Ptr=IncbinPtr("incbinlen.bmx")
Local bytes=IncbinLen("incbinlen.bmx")

Local s$=StringFromBytes(p,bytes)

Print "StringFromBytes(p,bytes)="+s$

Include[edit]

Description: Include effectively 'inserts' the specified file into the file being compiled.

Framework[edit]

Description: Framework builds the BlitzMax application with only the Module specified rather than all modules installed.

Comment: If you specify some module with Framework, only that module and ones it imports are compiled with your code. You can then import additional modules using Import. Common framework modules are Brl.Basic and Brl.Max2D, for console and 2d applications respectively.

Import[edit]

Description: Import declarations from a Module or source file

Example:

Rem
:Import specifies the external BlitzMax modules and source files used by the program.
End Rem

Framework BRL.GlMax2D

Import BRL.System

Graphics 640,480,32

While Not KeyHit(KEY_ESCAPE)
        Cls
        DrawText "Minimal 2D App!",0,0
        Flip
Wend

Assert[edit]

Description: Throw a RuntimeError if a condition is False

Comment: Assert throws a runtime error in Debug mode.

Example:

Rem
Assert generates a BlitzMax runtime error if the specified condition is false.
End Rem

a=LoadImage("nonexistant image file")
Assert a,"Image Failed to Load"

Goto[edit]

Description: Transfer program flow to specified label

Comment: Goto does not work in SuperStrict or Strict mode. Also, labels are limited to DefData.

Example:

Rem
Causes program execution to jump to the #label specified.
End Rem

Print "one"
Goto here
Print "two"
#here
Print "three"

Try[edit]

Description: Begin declaration of a Try block

Comment: A Try block attempts to catch an exception that might have been thrown between Try and Catch and attempts to handle the exception (instead of ending the program).

Example:

Rem
Begin declaration of a Try block.
End Rem

Try
        Repeat
                a:+1
                Print a
                If a>20 Throw "chunks"
        Forever
Catch a$
        Print "caught exception "+a$
EndTry

EndTry[edit]

Description: End declaration of a Try block

Example:

Rem
EndTry
EndTry marks the end of a Try block.
End Rem

Catch[edit]

Description: Catch an exception Object in a Try block

Example:

Rem
Catch defines an exception handler following a Try..EndTry Block.
End Rem

Try
        Repeat
                a:+1
                Print a
                If a>20 Throw "chunks"
        Forever
Catch a$
        Print "caught exception "+a$
EndTry

Throw[edit]

Description: Throw an exception Object to the enclosing Try block

Example:

Rem
Throw generates a BlitzMax exception.
End Rem

Try
        Repeat
                a:+1
                Print a
                If a>20 Throw "chunks"
        Forever
Catch a$
        Print "caught exception "+a$
EndTry

DefData[edit]

Description: Define class BASIC style data

Example:

' defdata.bmx

ReadData name$
ReadData age,skill

Print "name="+name+" age="+age+" skill="+skill

DefData "Simon",37,5000

ReadData[edit]

Description: Read classic BASIC style data

RestoreData[edit]

Description: Restore classic BASIC style data

Example:

' restoredata.bmx

For i=1 To 5
        RestoreData mydata      'reset the data pointer everly loop so we don't read past the end
        ReadData name$,age,skill
        Print "name="+name+" age="+age+" skill="+skill
Next

#mydata 'program label that can be used with the RestoreData command

DefData "Simon",37,5000

And[edit]

Description: Conditional 'And' binary operator

Example:

Rem
And is a boolean operator that performs the AND function.
End Rem

For i=1 To 10
        If i>3 And i<6 Print "!" Else Print i
Next

Or[edit]

Description: Conditional 'Or' binary operator

Example:

Rem
Or is a boolean operator that performs the OR function.
End Rem

For i=1 To 5
        If i=2 Or i=4 Print "!" Else Print i
Next

Not[edit]

Description: Conditional 'Not' binary operator

Example:

Rem
Not is a boolean unary operator that performs the NOT function.
End Rem

Print Not 0             'prints 1 (TRUE)
Print Not 20            'prints 0 (FALSE)

Shl[edit]

Description: Bitwise 'Shift left' binary operator

Example:

Rem
Shl is a binary operator that performs the shift to left function.
End Rem

b=1
For i=1 To 32
        Print Bin(b)
        b=b Shl 1
Next

Shr[edit]

Description: Bitwise 'Shift right' binary operator

Example:

Rem
Shr is a binary operator that performs the shift to right function.
End Rem

b=-1
For i=1 To 32
        Print Bin(b)
        b=b Shr 1
Next

Sar[edit]

Description: Bitwise 'Shift arithmetic right' binary operator

Example:

Rem
Sar is a binary operator that performs the arithmetic shift to right function.
End Rem

b=$f0f0f0f0
For i=1 To 32
        Print Bin(b)
        b=b Sar 1
Next

Len[edit]

Description: Number of characters in a string or elements in an array

Comment: You can also use the length field of an array or string as they are objects.

Example:

Rem
Len is a BlitzMax operator that returns the number of elements in a container Type.
End Rem

a$="BlitzMax Rocks"
Print Len a$    'prints 14

Local b[]
Print Len b             'prints 0

b=New Int[20]
Print Len b             'prints 20

Abs[edit]

Description: Numeric 'absolute value' unary operator

Example:

Rem
Abs is a mathematical operator that performs the Absolute function.
End Rem

For f#=-1 To 1 Step 0.125
        Print "Abs "+f+"="+Abs f
Next 

Mod[edit]

Description: Numeric 'modulus' or 'remainder' binary operator

Example:

Rem
Mod is a mathematical operator that performs the Modulo function.
End Rem

For i=6 to -6 Step -1
        Print i+" Mod 3="+(i Mod 3)
Next 

Sgn[edit]

Description: Numeric 'sign' unary operator

Example:

Rem
Sgn is a mathematical operator that returns the sign of a value.
End Rem

Print Sgn 50    '1
Print Sgn 0     '0
Print Sgn -50   '-1

Min[edit]

Description: Numeric 'minimum' builtin function

Returns: The lesser of the two numeric arguments

Max[edit]

Description: Numeric 'maximum' builtin function

Returns: The larger of the two numeric arguments

Varptr[edit]

Description: Find the address of a variable

Example:

Rem
Varptr returns the address of a variable in system memory.
End Rem

Local a:Int
Local p:Int Ptr

a=20
p=Varptr a
Print p[0]

SizeOf[edit]

Description: Size, in bytes, occupied by a variable, string, array or object

Example:

Rem
SizeOf returns the number of bytes of system memory used to store the variable.
End Rem

Type MyType
        Field a,b,c
End Type

Local t:MyType
Print SizeOf t  'prints 12

Local f!
Print SizeOf f  'prints 8

Local i
Print SizeOf i  'prints 4

Local b:Byte
Print SizeOf b  'prints 1

a$="Hello World"
Print SizeOf a  'prints 22 (unicode characters take 2 bytes each)

Asc[edit]

Description: Get character value of the first character of a string

Example:

Rem
Asc returns the unicode value of the first character of a string.
End Rem

Print Asc("A")        '65
Print "A"[0]  '65 - equivalent index style implementation

Chr[edit]

Description: Create a string of length 1 with a character code

Example:

Rem
Chr returns a String of length 1 containing the unicode character of the value.
End Rem

Print Chr(65)   'A