BBC BASIC for Windows

Introduction and Overview

Introduction to BBC BASIC

BBC BASIC for Windows is an advanced version of BBC BASIC which is fully integrated into the Microsoft Windows™ operating environment (Windows 95, 98, Me, NT4, 2000, XP, Vista or Windows 7), providing the programmer with a familiar language but with an up-to-date user interface. It combines the simplicity of BASIC with the sophistication of a modern structured language, allowing you to write utilities and games, use sound and graphics, perform calculations and create complete Windows™ applications.

Getting Started

If you've programmed in BASIC before, but aren't familiar with BBC BASIC, then you might like to dip into some of the tutorial chapters which cover differences between BBC BASIC and other dialects. You can also browse this manual or look up particular features which don't seem to work the way you're used to. The General Information chapter may be of particular interest.

If you are used to earlier versions of BBC BASIC (on the BBC Micro, on the Acorn Archimedes or BBC BASIC (86) on a PC) you may find the user interface somewhat unfamiliar. When you start BBC BASIC for Windows you are presented with a blank editing window into which you can type your BASIC program. Commands such as Load, Save, Chain, New and Renumber are activated by clicking with the mouse on drop-down menus or (in some cases) toolbar buttons, as is usual for Windows programs. There are also keyboard shortcuts for all the commands.

Once you have typed in, or loaded, your BASIC program you can run it by selecting the Run command from the Run menu or by clicking on the button in the toolbar. A second window will open in which appears any output from the BASIC program; error messages also appear here.

If you don't want to run a BASIC program, but simply want to enter commands for immediate execution (rather like a calculator) then select the Immediate Mode command from the Run menu, or click on the button. A second window will open into which you can type BASIC statements, in the same way as you could with previous versions of BBC BASIC.

Overview

A unique feature is the incorporation of an assembler which generates 32-bit code and accepts all 80486 instructions and some Pentium-specific instructions (except special-register and privileged instructions), including floating-point and MMX instructions. You can access the Windows™ Application Program Interface both from BASIC and from assembler code, allowing an experienced programmer to produce sophisticated applications.

The full version provides up to 256 Mbytes of user memory and allows you to create compact (typically less than 100K) stand-alone executable (.EXE) files from your BASIC programs, which will run without BBC BASIC having to be installed and without the need for any special DLLs. You can distribute such executables freely without any royalty being due.

BBC BASIC for Windows is largely compatible with Version 5 of BBC BASIC resident in the Acorn Archimedes and Iyonix computers. It also retains a high degree of compatibility with the BBC Microcomputer, including emulation of the SOUND statement and the MODE 7 (teletext) screen mode.

In addition there are a number of major enhancements over these early versions, including data structures, an EXIT statement, PRIVATE variables, long strings, NUL-terminated strings, event interrupts, an address of operator, byte variables and arrays, a line continuation character, indirect procedure and function calls and improved numeric accuracy.

Running BBC BASIC

• Select it from the Start Menu (usually Start ... All Programs ... BBC BASIC for Windows).

• Double-click on its desktop icon.

• Double-click on BBCWIN.EXE (usually in C:\Program Files\BBC BASIC for Windows).

• At a command prompt issue the command BBCWIN (assuming that BBCWIN.EXE is in the current directory, or is on the PATH).

• Drag the BASIC program and drop it on the BBC BASIC for Windows icon.

• Right-click on the BASIC program and select edit from the list.

• At a command prompt enter the command BBCWIN progname where progname is the name of the BASIC program you want to load (assuming that BBCWIN.EXE is in the current directory, or is on the PATH).

Minimum system requirements

• IBM-compatible PC with 80386DX or later processor.

• 16 Megabytes or more of Random Access Memory.

• VGA or higher resolution display.

• 3 Megabytes or more of free hard disk space.

• Microsoft Windows™ 95, 98, Me, NT4, 2000, XP, Vista or Windows 7 (32-bit); compatibility with 64-bit versions of Windows™ is not guaranteed.

For the SOUND statement to work correctly, your processor clock speed should be 133 MHz or higher.

Specification

Memory available for user's program, data and stack	Default approximately 1 Mbyte, maximum 256 Mbytes (depending on amount of RAM installed)
Size of BASIC program	Limited only by available memory (maximum 65535 numbered lines)
Length of program lines	Maximum 251 characters (tokenised) excluding line number
Integer variables	32 bits, signed (–2147483648 to +2147483647)
Floating-point (real) variables	Default 32-bit mantissa plus 8-bit exponent (±5.9E–39 to ±3.4E38); accuracy approximately 9 significant figures. Optionally 53-bit mantissa plus 11-bit exponent (±2.3E–308 to ±1.7E308); accuracy approximately 15 significant figures.
String variables	Maximum length 65535 8-bit characters
Array variables	Maximum number of dimensions 255, maximum size of each dimension limited only by available memory
Number of variables	Limited only by available memory
Length of variable names	Limited only by available memory and maximum line length
Levels of nesting	Limited only by available memory

Example programs

Most of these programs will run using the trial version of BBC BASIC for Windows, although (depending on which programs you have run beforehand) you may need to restart the application first to free up memory. A few of them (notably ASMTEST.BBC, DLGEDIT.BBC, FLIER.BBC, POEM.BBC, SEARCHBBC.BBC, SORTTEST.BBC and the file-handling demonstrations) require more than the 8K of user memory available with that version.

The example programs are located in sub-folders under the following categories:

FILING

GAMES

GENERAL

GRAPHICS

SOUNDS

TOOLS

WINDOWS

Differences from BBC BASIC (86)

• Line numbers may be omitted, except where they are required as the destination of a GOTO, GOSUB or RESTORE.
• Keywords may optionally be accepted and displayed in lower-case.
• The following BASIC V statements are accepted:
  • CASE... OF... WHEN... OTHERWISE... ENDCASE
  • CIRCLE [FILL] x,y,r
  • ELLIPSE [FILL] x,y,a,b
  • ERROR n, "string"
  • FILL x,y
  • Multi-line IF... THEN... ELSE... ENDIF
  • INSTALL "libfile"
  • LINE x1,y1,x2,y2
  • MOUSE x,y,b
  • MOUSE ON n
  • MOUSE OFF
  • OFF
  • ORIGIN x,y
  • QUIT
  • RECTANGLE [FILL] x,y,dx,dy [TO xnew,ynew]
  • SWAP var,var
  • WHILE... ENDWHILE
• The following BASIC V functions are accepted:
  • DIM(array())
  • DIM(array(), n)
  • GET$#file
  • REPORT$
  • SUM(array())
• The following BASIC V operators are accepted:
  • +=
  • –=
  • <<
  • >>
  • >>>
• The following statements have new forms:
  • BPUT #file, string$
  • COLOUR l,p
  • COLOUR l,r,g,b
  • GCOL c
  • LOCAL array()
  • ON
  • ON CLOSE
  • ON MOUSE
  • ON MOVE
  • ON SYS
  • ON TIME
  • PLOT x,y
  • PLOT 160-207
  • RESTORE ERROR
• You can assign a whole array, or set the elements of an array to constant values:
  • A() = B()
  • A$() = B$()
  • A() = 1,2,3
  • A$() = "one","two","three"
• You can assign to a sub-string:
  • LEFT$(A$,N) = string$
  • MID$(A$,N,M) = string$
  • RIGHT$(A$,N) = string$
• You can access the Windows™ Application Program Interface with the SYS statement.
• You can use binary constants, e.g. %01011111.
• The resident assembler generates 32-bit code and accepts all 80286, 80386 and 80486 instructions (except special-register and privileged instructions). A few Pentium instructions (notably CPUID) are also accepted.
• The assembler accepts 'jmp short', 'jmp far' and 'call far' as alternatives to 'jmps', 'jmpf' and 'callf'.
• The assembler accepts 'byte', 'word' and 'dword' as alternatives to 'byte ptr', 'word ptr' and 'dword ptr'.

Version 2 enhancements

Program editor and user interface

• Drag and Drop editing is implemented. You can drag and drop a selected (highlighted) block of text either within the editing pane or between BBC BASIC for Windows and any other program supporting drag-and-drop. This can be used as an alternative to the clipboard.

• The mouse wheel (if present) can be used to scroll the editing pane, without the necessity to load a special mouse driver. This requires Windows™ 98 or later.

• An unsaved program is automatically written to disk as a temporary file before it is executed. If the program crashes BASIC, it will automatically be reloaded the next time BBC BASIC for Windows is run.

• The List Variables utility has 'proportional' scroll bars.

BASIC interpreter

• Real (floating-point) variables can optionally be selected as 64-bits rather than 40-bits, using the *FLOAT command. This increases their accuracy from approximately 9 significant figures to approximately 15 significant figures.

• The built-in assembler can accept floating-point instructions.

• Floating point indirection is implemented, using the | symbol.

• An address of operator has been introduced (similar to C's & operator) using the ^ symbol.

• The LOCAL DATA and RESTORE DATA constructs are implemented. Also RESTORE +n is available to set the data pointer relative to the current line.

• The SUM function works for string arrays as well as numeric arrays (it returns a concatenation of all the array elements). Also the SUMLEN function is implemented, to return the total length of all the strings in an array.

• The compound assignment operators (+=, –= etc.) work with entire arrays; for example A() += B() adds each element of B() to the corresponding element of A().

• Untrappable errors report in a Message Box, ensuring they can always be read.

• The Backspace key can be redefined using *KEY 24. In particular this allows the key to return the DEL code (127) rather than BS (8) which can improve compatibility with some BBC Micro programs.

• VDU 23,7 is implemented to scroll the 'screen' (BASIC's output window) in any direction (up, down, left or right).

• The MODE statement positions the window (when possible) so that none of it is hidden by the task bar or is off the edge of the screen.

• The GET or INKEY codes returned by Alt plus a function key can also be generated by the key combination Ctrl+Shift+<function key>.

Version 3 enhancements

Program editor and user interface

• The status bar displays the length of the current program.

• If any of the program is selected (highlighted) Print defaults to 'print selection'.

• In Trace mode, single stepping into an INSTALLed module leaves the highlight on the last 'visible' statement.

• In the program editor CTRL/ and CTRL/ are word left and word right respectively.

• Find and Replace save the original scroll position in the go back list, so you can easily return to the starting point.

• Out-of-sequence line numbers result in an error message if the Run command is issued.

• The DEF keyword is (optionally) highlighted in a different colour.

• The Save command issues a warning if the file you are about to save has been modified by another application since it was originally loaded (for example by another copy of BBC BASIC for Windows). This reduces the danger of accidentally overwriting a later version of your BASIC program.

• The Compile command provides extra options: to set the initial client (rather than window) size and to separately enable different aspects of the crunch operation.

BASIC interpreter

• The maximum string length is increased from 255 to 65535 characters. This applies to string variables (string$), fixed strings ($address) and string arrays.

• The keyword PRIVATE is introduced. This is syntactically equivalent to LOCAL, except that the variables hold their values from one call of the function/procedure to the next. It is similar in operation to the 'C' keyword static.

• LOCAL and PRIVATE arrays are supported. LOCAL arrays are allocated on the stack, and are freed when the FN or PROC is exited. PRIVATE arrays are allocated on the heap, but can be accessed only in the FN/PROC in which they are declared.

• DIM <numvar> LOCAL <expr> is implemented. This allocates space from the stack rather than from the heap, and can be used only in a function or procedure. The space is automatically freed on exit from the FN/PROC in which it was claimed.

• Variables may be passed by reference to procedures and functions using the RETURN syntax. This also allows a FN/PROC to return multiple values to the caller, and the creation of variables with names determined at run-time.

• Array arithmetic is implemented, including the dot product A() = B().C()
  Array operations can be cascaded, although higher priority operators (e.g. * and /) must come first:
  A() = B() * 2 / C() + 3 - A()

• The MOD function returns the modulus (square-root of the sum of the squares of all the elements) of a numeric array.

• The assembler will accept the no-operand variants of fadd, fsub, fmul and fdiv.

• If bit 3 of OPT is set (values 8-15) the assembler will check the code address (P% or O%) against the value of L%. Hence
  DIM P% 100, L% -1
  will cause the assembler to issue an error if the code size exceeds 101 bytes.

• In an INPUT statement, or at the immediate-mode prompt, CTRL/V pastes in the contents of the clipboard (if any).

• MOUSE TO and MOUSE RECTANGLE are implemented.

• A user-defined mode can have a white background by adding 128 to the final (character set) parameter.

• If OPENIN, OPENUP or OPENOUT is passed a filename starting with a wildcard (*), the 'Open' dialogue box is displayed.

• The @dir$ system variable returns the directory from which the program (whether .BBC or .EXE) was loaded. This is very useful when INSTALLing library files.

Operating System interface

• The command *HARDCOPY is implemented to copy a graphical region of the screen to the printer.

• The command *REFRESH OFF disables the automatic screen refresh. *REFRESH ON enables the automatic refresh and *REFRESH forces an immediate refresh. These can be useful in reducing the flicker associated with an animated display.

• OSCLI (and *) commands which take decimal parameters can accept negative values.

Compatibility considerations

• The string descriptor has a different format, to accomodate the maximum string length of 65535 characters. Programs can access the string descriptor via assembly language or by means of indirection.

• The maximum number of characters read from a file by GET$# is 65535 characters. Some programs may assume that no more than 255 characters will be read.

• When an entire array is made LOCAL, earlier versions leave the array dimensions unchanged. Versions 3.00a and later leave the array in an undimensioned state, requiring a DIM to be added within the function or procedure.

• Earlier versions draw dotted and dashed lines with opaque gaps. Versions 3.00a and later draw them with transparent gaps.

• The function RND(n), where n > 1, returns different values, which may be apparent if used to produce a specific sequence by means of a seed. RND and RND(1) are unaffected.

• Earlier versions were tolerant of out-of-sequence line numbers.

Version 4 enhancements

BASIC interpreter

• Structures are implemented. Using structures and arrays of structures you can group together related data items and handle them as a single entity.

• Byte variables are implemented, using the & character as a suffix. They are particularly valuable as structure members.

• The @lib$ system variable is introduced, which points to the directory (folder) containing the standard library files. You no longer have to modify your programs according to where BBC BASIC for Windows was installed.

• The assembler accepts MMX opcodes.

• Backslash (\) is used as a line continuation character, allowing you to split program lines if they become too long or to improve clarity.

• Setting bit 23 of @% (&800000) causes a decimal comma rather than a decimal point to be printed.

• END, MODE and WIDTH may be used as functions (END returns the address of the first byte above the heap).

• WAIT can be used to pause a program for a specified number of centiseconds.

• RIGHT$(A$) is shorthand for RIGHT$(A$,1); LEFT$(A$) is shorthand for LEFT$(A$,LENA$-1).

• The keyword BY is introduced, signifiying that the coordinates specified in DRAW, FILL, MOVE and PLOT are relative rather than absolute.

• RECTANGLE SWAP (also PLOT 249 and 253) swaps two rectangular areas.

• The array dot product works with 1D as well as 2D arrays.

• In *FLOAT64 mode INT can be used with values up to ±2^50.

• LOCAL is accepted even after a LOCAL DATA or ON ERROR LOCAL statement.

Operating System interface

• The *HARDCOPY command may have the destination parameters omitted, in which case it automatically fits the plot to the page. If all the parameters are omitted it plots the entirety of BASIC's output window.

• The *LIST command lists to the screen an internal-format (tokenised) BBC BASIC for Windows program file.

Compiler

• Libraries and other 'resource' files (font files, image files, sound files etc.) can be incorporated within the executable file, and are automatically copied onto the destination PC when the program is run.

• The program and any embedded files can optionally be encrypted, to make it much harder for their contents to be discovered by examining the executable file.

• Compiled BBC BASIC for Windows executables have a different default icon from BBC BASIC (.BBC) program files.

• If the crunch operation fails, more detail of the problem is given and the offending statement is highlighted.

• Executable files generated by the compile utility can be successfully compressed using packing utilities such as UPX.

Program editor and user interface

• The Printer Font can be specified independently of the screen font.

• The Run To Cursor command is implemented. This causes your program to pause as soon as it reaches the line containing the text cursor (caret).

• The following improvements have been made to the right-click Context Menu:
  • If the menu is too large it is split into multiple pages. The maximum width and height can be customized.
  • ON ERROR, ON SYS etc. are optionally included within the list of procedures and functions.
  • Right-clicking on PROC or FN provides a quick means of scrolling to that procedure or function.

• The number of Undo levels is customizable.

• The acceptance of keyword abbreviations (e.g. P. for PRINT) is customizable.

• The initial amount of memory available for user programs is customizable.

• You can specify a default program which is loaded automatically every time BBC BASIC for Windows is started.

• The Run, Pause and Step commands have the keyboard shortcuts F9, F8 and F7 respectively.

• The number of lines scrolled by each 'notch' of the mouse wheel is determined by the Control Panel settings (on Windows™ NT4, 2000, XP and Vista).

• The Help menu contains a command to take you to the Yahoo™ BBC BASIC Discussion Group.

Compatibility considerations

• Because dot (.) has a new use as a structure member delimiter, PRINT statements may be interpreted differently. For example the following statement:

  PRINT s.3
  

  would be interpreted in versions prior to 4.00a as printing the variable s followed by the numeric constant 0.3. In version 4.00a and later it would be interpreted as printing the member named 3 of the structure s{}. To restore the original meaning add at least one space between s and .3.

• Because ampersand (&) has a new use as a byte variable type suffix, PRINT statements may be interpreted differently. For example the following statement:

  PRINT a&12
  

  would be interpreted in versions prior to 4.00a as printing the variable a followed by the hexadecimal constant &12. In version 4.00a and later it would be interpreted as printing the byte variable a& followed by the decimal constant 12. To restore the original meaning add at least one space between a and &12.

• Because backslash (\) has a new use as a line continuation character, it cannot always be used as an assembler comment delimiter. In such cases change the backslash to a semicolon (;) which is the preferred comment delimiter in 80x86 assembly language code.

• BY is a keyword. Programs using BY as a variable name may need to be amended (for example change BY to By).

Version 5 enhancements

BASIC interpreter

• The shorthand forms LEFT$(A$) and RIGHT$(A$), equivalent to LEFT$(A$,LENA$-1) and RIGHT$(A$,1) respectively, can also be used on the left of an equals sign to assign new values to the appropriate sub-strings.

• The new functions GET(X,Y) and GET$(X,Y) return the character at the specified text coordinates.

• The statements ON CLOSE LOCAL, ON MOUSE LOCAL, ON MOVE LOCAL, ON SYS LOCAL and ON TIME LOCAL are implemented. These can be used within a function or procedure and restore the previous event trapping (if any) on exit.

• Indirect procedure and function calls may be made, allowing a program to determine which procedure or function is called at run time in a more flexible way than is possible using ON PROC or EVAL.

• Procedure or function names may be passed as parameters to procedures and functions.

• The CALL statement can be used with a string parameter to execute BASIC program code in a specified file. For example, the file may contain declarations of constants or structure definitions. The code is discarded after it has been executed.

• The REPORT statement and the REPORT$ function include the filename of the CALLed or INSTALLed module in which the last error occurred, if applicable.

• Structure prototypes are implemented. You can declare a structure, sub-structure or structure-array to have the same members and layout as a previously-declared structure.

• (Version 5.10a and later only) NUL-terminated strings may be written and read by means of the $$ indirection operator.

Operating System interface

• The *TEMPO command allows you to set the units of the duration parameter of the SOUND statement.

• The *SYS command enables the trapping of additional Windows™ messages using ON SYS.

• The thickness of straight lines and outline shapes (drawn with DRAW, LINE, CIRCLE, ELLIPSE, RECTANGLE etc.) can be controlled using the system variable @vdu%!248.

Compiler

• The icon selected for the executable file is no longer restricted to 16-colours and 32x32 pixels. You can choose an icon which has multiple variants such as 256-colours or 48x48 pixels. This facility is available only when BBC BASIC for Windows is running under Windows™ NT 4.0 or later.

• You can enable Windows XP Visual Styles for the executable file. Executables generated using this option will have a more modern appearance when run under Windows™ XP or Vista. This option is available only when BBC BASIC for Windows is running under Windows™ NT 4.0 or later.

• You can optionally crunch embedded BBC BASIC (.BBC) program files and libraries, as if they were part of the main program.

• The executable file is stored, by default, in the exe subdirectory of the directory (folder) containing the source program file.

Program editor and user interface

• Error reporting is improved. If an error occurs at run time (even if trapped with ON ERROR) the statement responsible is highlighted in the editor. Hovering the mouse over the highlighted statement causes the error message to be displayed in a tooltip.

• Windows XP Visual Styles are used, when running under Windows™ XP or Vista.

• The Search menu no longer exists, and the Find and Replace menu options have been moved to the Edit menu as is now conventional.

• Indentation can be enabled or disabled 'in one go' with the Enable Indentation menu option.

• You can Add REMs to, or remove REMs from, every line in a selected block using a right-click context menu option.

• There are a number of other minor improvements to the user interface, including:
  • The Enter key moves the cursor (caret) to the current indent position (unless the previous line has a line number).
  • The File...Load and File...Insert dialogue boxes list .BBC and .BAS files together.
  • There are new keyboard shortcuts.
  • The Customize dialogue box has a 'browse for default file' button.
  • File...Insert doesn't change the current directory.

Compatibility considerations

• The size of the rectangle cleared by CLG, in the AND, OR, Exclusive-OR and Invert plotting modes, has been corrected. Programs which relied on the previous (incorrect) size may need to reduce the height and width of the graphics viewport by one pixel.

• The shift operators <<, >> and >>> no longer evaluate the shift count modulo-32. For shift counts greater than 32, results may well be different.

• Trailing commas in structure declarations are no longer permitted. For example the declaration DIM struct{a,b,} will result in a Mistake error.

• You may need to move a previously-compiled executable into the exe subdirectory for the compile options to be read.

Version 5.5 enhancements

BASIC interpreter

• EXT# may be used on the left of the equals sign to set the file's length.

• QUIT takes an optional parameter that determines the program's exit code when compiled to a standalone executable.

Operating System interface

• WM_HELP, WM_CONTEXTMENU and WM_HOTKEY are added to the set of messages intercepted by *SYS 1.

• The AnimateWindow API function is supported.

Compiler

• Console-mode executables may be created.

• Compiler directives may be incorporated using special REM lines.

• You can specify variables that must not be abbreviated when crunched.

Program editor and user interface

• Compatibility with Windows Vista™ is improved.

• More highlighting options are available when printing a program.

• The program's output window has a different icon from the IDE window, so they are more easily distinguished in the task bar.

Version 5.6 enhancements

BASIC interpreter

• The EXIT FOR, EXIT REPEAT and EXIT WHILE statements are implemented.

• Variable names may now start with the keyword OF.

• Limited support for labels has been added, to aid conversion from other BASIC dialects (e.g. QBASIC).

Compiler

• The REM!Keep compiler directive can additionally be used to prevent abbreviation of procedure and function names.

• Crunched libraries can successfully call procedures and functions in the main program.

• Compiled executable files are now compatible with receiving a digital signature.

Program editor and user interface

• The Step Line debugging facility is implemented.

• The REM!Eject directive will force a new page when the program is printed.

• The Save As command automatically changes the file's extension to suit the selected file type.

• Confirmation is requested if an attempt is made to exit the IDE when the output window is still open.

Compatibility considerations

• EXIT is now a keyword, so programs using it as a variable name (similarly EXIT%, EXIT$ etc.) will need to be modified if re-tokenised, i.e. edited or imported as plain text.

• The OFF keyword must always be followed by a valid statement separator, e.g. a colon or end-of-line.

• If the Crunch embedded files option is used, all modules imported with INSTALL must be embedded in the executable to ensure consistent procedure and function names.

Version 5.7 enhancements

BASIC interpreter

• The function DIM(struct{}) returns the size of the structure, in bytes.

• The construction struct.array&() refers to the NUL-terminated string stored in that structure member, i.e. it is equivalent to $$^struct.array&(0).

• LOCAL arrays are DWORD-aligned, i.e. the first element is stored at an address which is a multiple of four.

Operating System interface

• The system variables @ox% and @oy% contain the offset (in pixels) between the 'output bitmap' and the window contents.

• The width of the text cursor (caret), in pixels, can be controlled using the VDU variable @vdu%!252.

• The *FONT command can select a 'symbols' font like WingDings.

Program editor and user interface

• When printing a program listing, blank lines at the top of a page are suppressed.

• You can drag-and-drop program files from Windows™ Explorer or the Search Results window into the editor. The existing program, if any, is replaced (this works in the same way as Notepad).

Version 5.8 enhancements

BASIC interpreter

• 64-bit floating-point (double) constants may be specified in *FLOAT 40 mode by adding a # suffix, for example 1.23# or PI#.

• The THEN keyword has been extended to aid conversion from other BASIC dialects (e.g. QBASIC).

VDU emulation

• VDU 23,10,18 now sets the width of the text cursor (caret), as an alternative to @vdu%!252.

• VDU 23,16 has been implemented to provide enhanced cursor movement control, e.g. support for right-to-left printing languages.

• VDU 23,23 now sets the thickness of solid lines and outline shapes, as an alternative to @vdu%!248.

Operating System interface

• Enhanced support for console mode programs has been provided by means of *INPUT 13 and *OUTPUT 14.

• *OUTPUT 15 now allows output to be redirected to the printer, for example making it easier to emulate LPRINT.

• High-numbered input/output devices (e.g. COM10: upwards) may now be accessed directly.

Compatibility considerations

• The place at which text output in VDU 5 mode 'wraps' from one line to the next may be different from earlier versions. If this is a problem you can probably compensate for it by using the new cursor movement control facility.

Version 5.9 enhancements

BASIC interpreter

• The @tmp$ and @usr$ system variables are introduced, containing the path to the Temporary directory and the user's Documents folder respectively.

• The @vdu{} structure is introduced, providing a more convenient and flexible way of accessing the VDU variables.

VDU emulation

• Multilingual (Unicode) text output is supported natively, providing full access to the Basic Multilingual Plane without recourse to the Windows API.

Operating System interface

• The OPENIN, OPENOUT and OPENUP functions now display a file selector dialogue box when a wildcard character (* or ?) appears anywhere within the file specification (not just at the beginning).

Compiler

• An error is generated if the cruncher detects an ENDCASE, ENDIF, OTHERWISE or WHEN not at the start of a program line.

Program editor and IDE

• The TAB key can be programmed to execute a macro (see the SETTAB example program).

• The Help menu now contains a link to the Conforums message board.

• The Utilities menu can be customised to run external utilities.

Notices

BBC BASIC for Windows is the Copyright © 2001-2012 of R. T. Russell. It is supplied for use on one computer at a time only. Neither the program nor its accompanying documentation may be copied for simultaneous use by the purchaser nor for use by anyone other than the purchaser.

Schools and colleges are granted permission to reproduce or adapt sections of this manual to support teaching in a classroom context.

The name BBC BASIC is used with the permission of the British Broadcasting Corporation.

The aPLib compression library is used with permission. Copyright © 1998-2009 by Joergen Ibsen, All Rights Reserved.

CONTENTS

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