|
| File       Log
| Author     Nicholas Marriott
| Version    n/a
| Date       n/a
|
| Copyright (c) Nicholas Marriott 2000
|

Date                    Changes
22nd November 1997      Added 'Log' file
                        Overhauled editing system - added cursor buffer
                        Simplified Plot_Cell__Content code
23rd November 1997      Rearranged 'Keys' source file
                        Rewrote key and cursor handling - added Move_Cursor
                        Finally fixed multiple bugs in Affix_Unit routine
                        Extended toolbox & updated relevant code
                        Fixed misnomer in 'Sprites' file
24th November 1997      Implemented some of the toolbox functions
                        Changed D-SELECT on sheet to select cell
25th November 1997      Restricted selection redrawing to only relevant cells
                        Fixed bug in Clear_Selection code
26th November 1997      Added size arrows to toolbox
                        Added quick font menu to toolbox
                        Created sort window
27th November 1997      Speeded up various procs by preventing unnecessary
                           calling of Calculate_Row
28th November 1997      Added message icon in ProgInfo window
29th November 1997      Fixed bug with cursor left in column 0
30th November 1997      Solved Copy key problem
02nd December 1997      Revamped constants redraw code
03rd December 1997      Un-revamped constants redraw code (the revamped code
                           doesn't work properly :-( 
06th December 1997      Implemented online help framework
                        Made loading of online help optional
09th December 1997      Partially added cell name conversion ("[7,5]" to 7,5)
                        Changed constants & move cell code to reflect above
                        Redesigned move cell window
                        Changed MessageWindow icon from 'Continue' to 'Close'
10th December 1997      Fixed bug with string constants
                        Added option to change decimal separator
14th December 1997      Finished Copy_Selection code
                        Adjusted shading of paste tool & menu item to deal with
                           no clipboard
18th December 1997      Added paste menu
                        Changed sprite icons in sort window to affect radio
                           icons on click
                        Updated paste tool and menu item to reflect state of
                           clipboard rather than selection
19th December 1997      Implemented paste functions
                        Added warning message to paste
                        Prevented crash if default icon shaded and RETURN used
                           in window
21st December 1997      Changed main window background to transparent
                        Added graphics code -- very messily
                        Rewrote Redraw_Cell code to find area to redraw then
                           redraw it, rather than using Wimp_UpdateWindow on
                           the entire window, which led to every graphic
                           being redrawn. Should increase speed...
22nd December 1997      Changed graphic icon on toolbox to move icon
                        Added query message to Restore defaults option
                        Changed Blank_Selection code to ignore cursor
                        Created ic_isis sprite
                        Included support for message WindowInfo (&400CC)
04th January 1998       Implemented cut function
                        Rearranged 'Resources' directory
10th January 1998       Added resize sheet window
14th January 1998       Implemented ADJUST-dragging on labels
                        Updated all files to read '1998' not '1997'
                        Fixed bug with help window
                        Added provision for double-click file loading
                        Moved misc. definitions into special 'Misc' file
                        Restricted recalculation of cursor cell size to happen
                           only if the cell has been edited
15th January 1998       Bug fix in cursor code
17th January 1998       Added code for altering sheet protection settings
                        Rearranged memory to allocate more space for window
                           handles
                        Implemented column/row selection from menu
                        Added fill menu
                        Toolbox size now read from window def. rather than
                           hardwired into code
18th January 1998       Fixed stupid graphic bug
                        Completed FileInfo window code
                        Allocated space for file name, size and date
                        Removed compression from banner files
                        Changed all code to use LZW module
                        Added save code
19th January 1998       Implemented error & free space checking for both
                           ultimate save file and scrap file
                        Added code for OK icon in save window. Good job I made
                           the save code kinda modular, eh?
                        Set message window to open in a more sensible position
20th January 1998       Fixed bug in options loading
                        Revamped error handling in graphics loading code
                        Entire data transfer protocol (except RAM transfer) is
                           now supported... oh, and not DataOpen...
                        Sorted out parameters of Wimp_SendMessage calls
21st January 1998       Altered code to ignore all messages from self
                        Added window to cover sheet corner
                        Mouse click on corner window now selects or deselects
                           entire sheet
                        Key pressed code tries to close message window
                        Fixed bug in constant creation
                        Minor change to font size calculation
22nd January 1998       Set corner window to close with sheet instead of just
                           sitting there all the time, which looked a bit silly
                        Noticed nasty problem with plotting but decided not to
                           fix it today, as it is too late... <yawn>
23rd January 1998       Added skeleton for loading routines
                        Removed message icon from ProgInfo window
24th January 1998       Message SaveDesktop (&0000A) now supported
25th January 1998       Moved graphics list into sheet data
                        Added error checking to compression and decompression
04th February 1998      Changed move window to have current cell as default
05th February 1998      Changed templates to avoid errors with WimpExtension
                           version 3.45
                        Moved open window SWI calls into libraries so as to
                           match with close window calls
                        Fixed inaccuracy in toolbox placement
06th February 1998      Made program fully (and exclusively) compatible with
                           WimpExtension 3.45
                        Changed labels redrawing to access block by register
                           rather than direct access
                        Added border to corner window
                        Made labels slab in to correspond with selection
                        Changed FileInfo window to SheetInfo window throughout
                        Moved sprites into static block (wastes 16Kb in
                           low-res, 2Kb in hi-res)
07th February 1998      Changed banner sprites to 4 colours to save memory
                        Removed 16Kb AlphaPro logo from ProgInfo box and
                           sprite file also to save memory
08th February 1998      Changed cell colour to be in standard palette entry
                           format
                        Implemented use of ColourPicker dialogue boxes to
                           change cell colours
                        Changed selection colour method
09th February 1998      Altered code to accept SOME messages from self, notably
                           numbers &47700 and &47702. Oh, and zero as well
                        Fixed various bugs in saving mechanism
                        Miscellaneous minor changes to 'Messages' file
                        Rearranged handles in source file
                        Added Tab key functionality
                        Added border icon in toolbox
                        Included another check for illegal cell ref. in cell
                           conversion code
                        Created a rather nice example sheet, if I may say so
                           myself. Unfortunately it can't be reloaded yet :-(
                        Added load/save/delete buttons to formula window
10th February 1998      Finally and with great difficulty fixed extremely
                           small (one instruction) bug in Locate_Cell code
                        Moved update refs. menu item to option menu
11th February 1998      Implemented fill functions
                        Reorganised request messages
12th February 1998      Changed program to use Acorn's Squash module and
                           removed all traces of LZW from every file
                        Fixed bug in paste code
                        Deleted my nice example sheet as it was in the file
                           format which used LZW :-(
                        Made SheetInfo window memory estimate include graphics
13th February 1998      Added row insertion code
                        Fixed bug in cursor size calculation
                        Added row deletion code
                        Included sheet size check
15th February 1998      Added hourglass to row insertion and deletion
20th February 1998      Added fix formulae option to selection menu
                        Included overlay menu and moved graphic menu to it
21st February 1998      Added SaveGraphic window
                        Added support for overlays and transferred graphic code
                        Fixed various bugs in new overlay code
                        Implemented insert/delete row buttons on toolbox
                        Fixed major bug which led to handles of 36th or later
                           window being overwritten
                        Fixed bug with alignment of base in some fonts
                        Made row deletion size checking work properly
22nd February 1998      Allowed text overlay colours to be changed
                        Shakily fixed bug with WimpExt and ColourPicker windows
                        Added editing of text overlays
                        Changed 'number' to 'number format' in window and on
                           menu
                        Miscellaneous minor changes to templates
23rd February 1998      Fixed bug with selection of overlays
                        Made new text overlays appear at +128 x & y from the
                           current scroll offsets
26th February 1998      Resculpted menu structure
28th February 1998      Compressed help messages using \ commands
06th March 1998         Sorted out overlay menu item shading
                        Reorganised toolbox
                        Changed to registered file type &177
07th March 1998         Constants window now uses desktop font
08th March 1998         Changed templates to use standard RISC OS 3d icons
                           rather than WimpExt ones
                        Rewrote various bits of code to omit WimpExt
                        Fixed bug with bg colour in constants list
09th March 1998         Changed default justification in window to centre
                        Removed WimpExt calls from other bits of code
10th March 1998         Changed labels redrawing to use Wimp_PlotIcon rather
                           than WimpExt_PlotBorder
14th March 1998         Changed font menus to not use WimpExt
                        Removed last traces of WimpExt from main code
15th March 1998         Started removing WimpExt from libraries
                        Fixed bug with sprite size calculation
17th March 1998         Changed font menu creation to use Font_ListFonts
                        Swapped to OS_Heap for heap management instead of
                           WimpExt_Heap. Only 3 more WimpExt calls to go!
18th March 1998         Adjusted graphic scale storage to store percentage
                           and convert to scale on plotting
                        Changed graphic transformation calculation and colour
                           translation to own code rather than WimpExt calls
                        Changed paste & fill icons on toolbox to open a menu
                           rather than simply assuming data only
                        Request window now responds to Return (Continue) and
                           Escape (Cancel)
                        Fixed bug with cell size calculation (cursor and normal
                           heights were different - r0 used instead of r1)
                        Added unit icon to toolbox
                        Blank units are now not accepted
19th March 1998         Changed error handler to display errors in a message
                           window and to mark library errors as internal
                        Fixed bug in cursor redrawing code
                        Rewrote memory move routines in libraries
                        Changed border icons on toolbox from one toggle to two
                           set and unset icons
21st March 1998         Removed unused error messages and rerouted file
                           messages to use error handler
                        Removed last WimpExt SWI, WimpExt_MemCopy, and recoded
                           column and row insertion and deletion code to use
                           new method
23rd March 1998         Rewrote insert column code to avoid crashing the whole
                           machine if called more than once
24th March 1998         Added delete column code
                        Fixed bug with cursor in last column
25th March 1998         Changed to proper on-the-fly redrawing of selection
                           of rows and columns
26th March 1998         Implemented above for normal selection, introducing
                           lots of bugs in the process
27th March 1998         Fixed bug in graphic size calculation
                        Changed selection colour method to invert fg & bg
                           colours rather than EORing with opposite
28th March 1998         Selection can now be changed using ADJUST
29th March 1998         Rewrote FP conversion code to handle scientific nos.,
                           included provision for thousands separation and
                           added various other bits
                        Fixed a few wee bugs to do with spurious decimal
                           points...
30th March 1998         Failed to do anything because of loadsa power cuts...
31st March 1998         Added facility to copy overlays
                        Fixed bugs in overlay code with text editing (always
                           affected first overlay due to r9 used instead of
                           r11), redrawing of colour icons in windows and
                           placement of data on copying (r7 instead of r3 this
                           time)
02nd April 1998         Removed problem with ADJUST on radio icons
05th April 1998         Added code skeleton for exporting
                        Wrote CSV & TSV export code
10th April 1998         Included graphic saving code
                        Replaced equz with equza throughout code
                        Used new version of Zap (1.3910) to spell check this
                           file!
                        Only covered area of screen is now redrawn when banner
                           is removed
11th April 1998         Program now copes correctly if no converters are
                           present - 'Export' option is shaded
                        Shortened minimum banner display time by s to 1s
                        Tried desperately to think of some way to speed up
                           assembly... it's over 4 minutes now!
12th April 1998         Yippee!! Done it! It's back down to only 1 minutes
                           again, due to on-the-fly tokenisation by the
                           source processor rather than by BASIC...
                        Added sheet searching facility
13th April 1998         Changed polling structure to use stack rather than
                           miscellaneous branches...
                        Recoded redrawing of both entire sheet and area to
                           (hopefully) speed it up...
                        Used Wimp_BlockCopy instead of redrawing entire sheet
                           for as-you-type resizing of cells, making it fast
                           enough to be usable
                        Separated sheet window extent and title adjustment
                           code to avoid title being redrawn unnecessarily
18th April 1998         Added warning if screen mode is too small for toolbox
                        Moved sprites back into heap block (OS_Heap blocks are
                           static so no risk of accidental relocation)
                        Moved __Hourglass_Off call to BEFORE initialisation of
                           error handler to avoid hourglass being left on
                        Replaced cmp with eq/ne result with teq. Why? Good
                           question :-) It did highlight some *nasty* bugs in
                           the Wimp library... notably that it would carry
                           on and attempt to change the window background if
                           it was passed as an icon number
19th April 1998         'Messages' file is now stored in a dynamic area if
                           they are available. I would store them in a heap
                           block but the heap routines require some
                           MessageTrans calls so they must be initialised
                           first :-(
                        Implemented UpCall and Exit handlers since the PRM
                           says: "You *must* provide all three of these
                           handlers if you use any handlers at all." So there.
20th April 1998         Fixed bug in colour picker code
                        Fixed bug in perimeter detection when selecting rows
                           or columns (if the row/column was already selected,
                           it wouldn't scroll)
                        Did you know that this file is now 2,158 words?
                        Changed format of list displays
                        Fixed major (heap-corrupting) bug in deletion of items
                           from constants list (actually, it applied to all
                           lists of any type but this is the only place it is
                           used)
24th April 1998         Added macros to the assembly source processor!
                           Unfortunately, this slows assembly down again :-(
25th April 1998         Completed cell name conversion. "ABC12" now translates
                           properly to 730,12
                        Fixed a few bugs in the above and related code
28th April 1998         Removed minor bug in cell size changing code
29th April 1998         Fiddled with key settings -  amd  now move to
                           start and end of cell rather than to the next
                           and  and  move up or down three rows instead
                           of one
02nd June 1998          Made minor changes to templates
20th June 1998          CSV exporter now doubles double quotes in strings, so
                           a cell containing abc"def would become "abc""def".
                           I think that is the correct way to do it...
                        Fixed bug which always filled with blank rather than
                           cursor
21st June 1998          Redesigned help screens
                        Added interactive help to sheet corner window and
                           corrected a few other minor errors in help text
                        Wondered how they got the selection redrawing so quick
                           in Schema...
09th July 1998          Optimised cell plotting code and added timing code to
                           test it. It's amazing how much difference fonts
                           make: A selected, blank cell with the cursor in it
                           takes 0.87s to redraw 512 times compared with 2.76s
                           for a cell with the word 'Hello' in 12pt Homerton.
                           Medium. An unselected, blank cell without the cursor
                           takes 0.41s
                        Removed bug with certain messages (accidently used 
                           equs instead of equz... nasty)
                        Added modified flag handling amd all the associated
                           quitting paraphenalia
10th July 1998          Started Schema exporting code... but it doesn't work
                           properly... time to email Clares, methinks...
                        Fixed bug in protection window code
                        Fixed bug in PreQuit message code - the program was
                           not exiting if a shutdown was called
05th August 1998        Fixed Schema 2 export module - should exported numbers
                           be subject to the format applied to them in Isis
                           though?
06th August 1998        Major reorganisation of effects windows & menu, both
                           in structure and usage
                        Replaced font window with font menu and font size
                           window
                        Fiddled with colour picker dialogue box code. Failed
                           to fix bug
                        Minor alterations to templates
07th August 1998        Changed method of removing cpicker windows to make use
                           of the fact that only one may now be open at a time
                           and to fix oddity with fg. & bg. colours
24th August 1998        Removed extraneous spaces in 'Messages' file
25th August 1998        Rewrote Zeus source processor to automagically
                           exclude all library routines that are not actually
                           called... This makes almost no difference to Isis
                           as it uses virtually all of them...
                        Added pointer changes in the right places on toolbox
26th August 1998        Wrote __Squash_DecompressBlockFromFile library routine
                           and began work on the sheet loading code
27th August 1998        Fixed a few bugs in the decompression code (it always
                           chose the last instead of the first end marker
                           if there was more than one... grr...)
                        Added memory estimate to file format and memory
                           checking to load & save code
                        Completed all sheet loading code except for overlay
                           loading
                        Added support for DataOpen message
                        Included code to handle double-clicking on a file to
                           start Isis
                        Fixed problem where *every* DataOpen message was being
                           claimed...
                        Removed bug in paste effects code
                        Deleted useless ability to lock graphics
                        Attached sort & edit graphic windows to menu
                        Fixed minor bug with font menus
                        Added autosave code
28th August 1998        Added overlay loading code
                        Adjusted loading memory calculation to account for
                           buffers
                        Added function and control key functions where there
                           is code to be called
13th September 1998     Wrote code to load importers                           
19th September 1998     Added code to check if cell actually contained data or
                           effects before 'are you sure?' messages
                        Created width & height windows and added code to do
                          everything but actually change the values
                        Included ability to set minimum column width and row
                          height and updated file format (now version 1) to
                          include new data
20th September 1998     Made alteration of column width or row height set
                          the FileStatus flag
                        Redesigned toolbox to be much shorter
                        Fixed bug with backspace key
                        Allowed column width and row height to be set by
                           ADJUST-dragging on labels
                        Added help to width & height windows
21st September 1998     Fixed bugs in width and height adjustment
07th October 1998       Changed most windows to be centred when opened
13th October 1998       Added testing of V flag in export code
21st October 1998       Began work on formula code
                        Made option to 'show formulae' work
22nd October 1998       Fiddled with constants: added error on attempt to set
                           constant with no name and made constants be
                           marked by { and }
                        Set standard cell refs. to also require [ and ]
                           around them
23rd October 1998       Fixed bug with cursor not being changed on blank, fill,
                           cut et al
24th October 1998       Wrote extremely badly written infix->postfix converter
                           and interpreter 
30th October 1998       Fixed bug with delete/insert row/column corrupting the
                           width and height
                        Changed lists display slightly
12th November 1998      Added skeleton spell checking
13th November 1998      Finished spell checking code
                        Considered th easiest method to do sorting
14th November 1998      Fixed bug in spell checking code
22rd November 1998      Started complete rewrite of formula compiler to include
                           many more operations and allow easier inclusion of
                           string and function code
23rd November 1998      Completed main formula code: only strings, functions
                           and support for formula cell refs. need to be
                           included now
24th November 1998      Formula compliler now copes with strings - only
                           addition and if operations on strings are permitted
25th November 1998      Added code to handle function files
                        Fixed minor bug in list (constants, export & functions)
                           display code
                        Almost completed formula window
                        Fixed bug in Delete_Column where it was expanding
                           instead of decreasing the heap block... this led
                           to 5x10 sheets taking up about 40Kb!
                        Updated cell size to 256 bytes. Decided that I should
                           have designed a better method of storing cells
                           as with 256 bytes perhaps a little too much wasted
                           space... heap blocks perhaps? but not enough
                           anchors unless I lose the provision for a relocating
                           heap manager...
                        Updated file format to version 2 and declared versions
                           0 and 1 obsolete (have to for internal structure
                           changes such as a change in cell memory size...)
26th November 1998      Added comparision operators (==, !=, <, <=, >, >=) for
                           strings
                        Added function code to formula compiler... now to start
                           writing some functions!
                        Discovered really really really stupid bug where if the
                           program took longer than 1s to start up, it
                           hung...
28th November 1998      Fixed bug with functions parameters being reversed
                        Made labels NOT redraw on selection drag - much quicker
                        Adjusted exporters to work with formula cells
                        Wrote some more functions
28th November 1998      Added special operators 'X' and 'Y' to formula code
01st December 1998      Included support for '@' operator in cell references
                        Fixed (I hope...) bug with toggle size icon
                        Extended SaveDesktop message handling to include
                           filename, if valid 
03rd December 1998      Fixed a couple of bugs in NameFrom_Cell routine
                        Added ranges to formula compiler and wrote sum()
                           function
                        Fixed bug with ^Z and toolbox
                        Added enter icon to toolbox
                        Fiddled with cell length checks
05th December 1998      Expanded tokens in 'Messages' file again, as they won't
                           work on RISC OS 3.1...
07th December 1998      Wrote TaskControl module and added support to Isis
08th December 1998      Began work on demo. program
22nd December 1998      Rewrote functions list display code using more
                           efficient method
                        Fixed bug with paste
23rd December 1998      Added skeleton sheet evaluation code and fixed a few
                           minor bugs in various places
                        Realised that is has been over a year since I started
                           this log file...
                        Isis' main source file is now 19319 lines (458 Kb) plus
                           more than 230 library files comprising about another
                           250 Kb. Oh, and another 70 Kb of converter and
                           function source code... and the damn thing still
                           isn't finished!
                        Wished I had kept a record of when I actually started
                           coding... I think it was sometime in late 1996 or
                           early 1997...
18th January 1999       Changed help page style
26th January 1999       Added fix formulae code
                        Added misc. window key handling code to Key_Pressed
                        Added m_CORE_CLAIM and m_CORE_RELEASE TaskControl
                           message handling
27th January 1999       Changed to more logical naming of importers and
                           exporters, more in line with function naming system
28th January 1999       Finally fixed bug with negative exponents in 
                           __Number_FPToString code... time for another
                           FP rewrite though, I think: it needs to handle
                           thousand separation (such as 1,000,000),
                           conversion of strings containing numbers greater
                           than &FFFFFFFF, and conversion of e numbers.
29th January 1999       Added a rather awful hack to FP code in order to fix
                           problem with -ve exponent numbers and rounding.
                        Fixed the last major bug in the FP code, that of
                           something like 1.1111 being converted to 1.1110 in
                           fixed mode.
30th January 1999       Changed string to number conversion to handle more than
                           32-bit numbers
09th April 1999         Idly fiddled with templates
25th April 1999         Added cell reference updating code to fill and paste
                           code - both coord. and standard systems
                        Fixed bug in Fix_Selection code (missing ldr r9,[r10])
26th April 1999         Extended heap manager to solve problem with unreleased
                           blocks and heap corruption in formula code
                        Fixed bug with ^A and menu shading
22nd May 1999           Expanded sort window
                        Added basic sort _window_ functions
23rd May 1999           Fixed irritating bug with real-time selection redraw
                        Changed power operator to **
                        Removed selection indication by slabbing of labels -
                           _huge_ speed increase in redrawing
                        Added code to handle ADJUST on close icon
24th May 1999           Added deg() and rad() functions
                        Implemented the first and second types of sorting,
                           expanding the sort window appropriately
                        Added query before constants save
25th May 1999           Set redraw routines to only set the colour if is
                           different from last used and changed font handling
                           to store the font handle until the program is quit -
                           this expands the space required for each font to 192
                           bytes but gives a speed increase of about a half
                           when plotting one cell (down to 1.54 for the test
                           somewhere above)
                        Added checking for font availability on sheet loading
26th May 1999           Allowed formulae to access other formula cells and
                           adapted evaluation code to cope with forward
                           references
27th May 1999           First RFC release
30th May 1999           Redesigned help pages again
15th June 1999          Cursor now moves into inserted row or column. I've now
                           got only one more exam. to go!
                        Planned to fix Insert_Column bugs but didn't have the
                           time...
19th June 1999          Added indication of selection or cell size during
                           dragging
08th July 1999          Fixed a couple of bugs in help pages: cursed the
                           differences in plotting text areas between Draw
                           and the DrawFile module...
09th July 1999          Moved toolbox to top of window
                        Removed screen size warnings
                        Toolbox may now be scrolled by dragging
                        Hopefully fixed problems with window resizing and
                           positioning
                        Adjusted minimum cell size to 96 by 48 so as to fit
                           more on screen
                        Added pointer changes to row width/column height
                           adjustment
                        Fixed a couple of bugs in cell height calculation
28th July 1999          Fixed another bug in cell height calculation
30th July 1999          Added 'Create' option to iconbar menu
31st July 1999          Added importing code and wrote TSV importer
                        Fixed bug with attempts to load non-existent files
01st August 1999        Wrote rather messy CSV importer 
02nd August 1999        Extreme failure to add styles: ended up making a 
                           complete mess of the code so returned to backup
03rd August 1999        Simplified ColourPicker management code
                        Removed useless graph stuff
04th August 1999        Fixed bug with ADJUST on font menus
                        Removed Swap_Colours code & means to access it
                        Added styles code again and adapting effects to
                           allow them
                        Units now only apply to numbers
                        Updated file format to version 3 and added conversion
                           code
                        Styles seem a little unintuitive...
06th August 1999        Fixed bug with cursor plotting in blank cells
29th August 1999        Second RFC release
30th August 1999        Rewrote internal handling of in-use font handles to
                           escape maximum size of 256 and to avoid wastage of
                           1 to 256 bytes if less than 256 different sizes of
                           each font are used
                        Fixed bug with font menu decoding
01st September 1999     Totally redesigned help system to be text- not draw-
                           based.
                        Wrote a couple of the help pages.
                        Minor cosmetic changes to some windows
02nd September 1999     Added '-help' command line option
                        Completed sorting code
03rd September 1999     Added row and column headings code
                        Updated file version to 4
07th September 1999     MENU on labels opens correct heading window
08th September 1999     Added code to check for circular references - but had
                           to lose the forward reference checking code in the
                           process
                        Adjusted fill/paste effects code to keep circular ref.
                           flag
                        Fixed bug in Fill_Selection code
09th September 1999     Added automatic recalculation code
                        Fixed bug in cell range extraction from formulae
                        Tried yet again and hopefully managed to fix bug with
                           window stack position and toggle icon
                        Added 14 pt. font to help files for titles
                        Nothing now takes place (no automatic evaluation)
                           when the cursor moves from a cell _unless_ that
                           cell's contents has been changed. This assumes that
                           the sheet's integrity (correctness) is maintained
                           by all other code...
                        Added information retrieval (well, file version is the
                           only useful thing) from a file by loading it with
                           CTRL depressed
                        Fixed bug in Save_Cursor
10th September 1999     Fixed bug with column width calculation after
                           evaluation of a cell
                        Removed unnecessary Calculate_Row calls in some loops
                        ^E may now be used to force evaluation of a cell
                           without having to move the cursor from it
12th September 1999     Fixed a couple of mistakes in 'Messages' file
                        Fixed bug with preservation of temporary storage
                           between Evaluate_CellN and Paste_Selection code
13th September 1999     Redesigned print window and added pages window
                        Added code to sort out pages for printing
14th September 1999     Added printing code
17th October 1999       Moved some buttons in print & pages windows
                        Fixed bug in pages window handling code
29th October 1999       Added 'Clear' icon to formula window
                        Holding CTRL and clicking ADJUST now selects the
                           area between the cursor and the mouse pointer
30th October 1999       Added new memory copy routines by GUS
                        Fixed major bug with exporting of numbers (due to
                           styles...)
                        Added support for e numbers & some more constants
31st October 1999       Third RFC release
07th November 1999      Changed max. filename length in ExportWindow
                        Began converting Jon Ribbens' flex code from APCS to
                           normal assembler form and adding it to Isis
13th November 1999      Flex code completely converted; began adapting Isis to
                           cope with a relocatable block manager
                        Moved sprites back into static block: wastes about 9Kb
                           in low-res modes, almost zero in hi-res
14th November 1999      Fixed import & create sheet code
26th November 1999      Fixed load sheet code
27th November 1999      Altered __Heap_Release and __Heap_ListOp (2 & 3)
                        Fixed bug in memory copy surrounding code
28th November 1999      Fixed bugs in formulae code and rewrote heap list
                           handling
11th December 1999      Fixed heap problems in cell page allocation code for
                           printing
                        Added a couple more help pages
                        Fixed deg() and rad() inaccuracy problem
                        Added string-number and number-string comparisons
                           (!= and == only, != is always true, == is always
                           false)
                        Managed very cleverly to overwrite all my new help
                           pages with heap diagnostic files... <bow>
                        Updated heap resize code to prevent moving of blocks
                        Added error recording system
18th December 1999      Patched __Squash_CompressBlockToFile to fix strange
                           problem with small blocks
                        Discovered that some other aspects of that routine are
                           screwed...
29th January 2000       Realised not only that I'd done sod all on Isis for
                           over a month but also that string-number equality
                           comparisons don't work and I can't figure out why...
12th February 2000      Adjustments to error recording system (now shouldn't
                           crash if file can't be created/opened)
                        Fixed bug with cursor contents being maintained when a
                           new sheet loaded - and thus overwriting the contents
                           of cell [0,0] on the new sheet
26th February 2000      __Squash_CompressBlockToFile now works again but for
                           some reason only when block sizes are rounded up to
                           the nearest 32, like in the old heap manager - this
                           means some disc space is wasted in a saved file and
                           some memory when it is reloaded
27th February 2000      Sprites are now stored in a dynamic area
17th March 2000         Rewrote Insert_Row, including code to update formula
                           values
20th March 2000         Delete_Row now works okay
03rd April 2000         Tried to add combined cells a la Schema and Sheet but
                           failed: it could be done but would require major
                           rewriting and restructuring of a lot of redraw code
