LaurenceBoyd
Mar 19, 2014
[[toc]]
=XML for Data storage=
{{by {$creator} {$revisiondate} {$revisionid}}}
==XML==
XML is a flexible, convenient, way of storing data, once you understand how.
Programs typically evolve thru several versions. This often results in different data items being stored by different program versions. This has meant careful tracking of data version vs program versions, as programs could not correctly read data from the wrong data version.
XML is flexible as names are stored with the data. Names which are understood can be read, while others are ignored. The downside is that missing variables may require defaults.
XML is a very convenient to use. The rules are quite simple.
XML consists of elements:
<name> text </name>
Every opening <name> is paired with a closing </name).
Names can be almost anything but are case sensitive.
Elements can be wholly contained within other elements.
Elements cannot overlap.
<name1> <XYZ> </XYZ> </name1> legal
<name1> <XYZ> </name1> </XYZ> not legal
for more details visit: http://www.w3schools.com/xml/xml_syntax.asp
==Saving Data==
The following example shows only the code to open and write a file.
[[code format="lb"]]
sub FileSaveAs
filedialog "Save file", FilePath$+"*.Sudoku", FullName$
call GetFileName$
if FileName$="" then notice "No file chosen!": end
call FileSave
end sub
sub FileSave
open FullName$ for output as #File
FileOpen = True
#File "<XML>"
#File "<!-- "; Date$();" "; Time$();" ";FullName$;" -->" 'XML comment
#File " <Sudoku>"
call SaveOptions
call SaveCells
#File " </Sudoku>"
#File "</XML>"
close #File
FileOpen = False
notice "Puzzle Saved ";chr$(13);_
"File Name ";FileName$;chr$(13);_
"at ";FilePath$
end sub
sub SaveCells
for row = 1 to 9: for col = 1 to 9
if CellValue(row,col) <> 0 then
call SaveOneCell row, col, CellValue(row,col), CellStage(row,col)
end if
next col: next row
end sub
sub SaveOneCell row,col,value,stage
#File " <Cell> ";
#File "<Row> ";row;
#File " </Row>";
#File "<Col> ";col;
#File " </Col>";
#File "<Value> ";value;
#File " </Value>";
if stage <> 1 then
#File "<Stage> ";right$(" ";str$(stage),2);
#File " </Stage>";
else
#File " "
end if
#File " </Cell>"
end sub
sub SaveOptions
#File " <Size> ";9;" </Size>"
#File " <Diagonal>";
if DiagActive then #File " On "; else #File " Off ";
#File "</Diagonal>"
#File " <Possible>";
if PossibleShow then #File " On "; else #File " Off ";
#File "</Possible>"
#File " <Reduce> ";
if ReduceActive then #File " On "; else #File " Off ";
#File "</Reduce>"
end sub
sub GetFileName$
for pos = len(FullName$) to 1 step -1
if mid$(FullName$, pos, 1) = "\" then exit for
next pos
FileName$ = mid$(FullName$,pos+1)
FilePath$ = left$(FullName$,pos)
end sub
[[code]]
==Example data file:==
[[code format="xml"]]
<XML>
<!-- Mar 12, 2014 10:56:25 C:\Data\Sudoku\3.40.88.Sudoku -->
<Sudoku>
<Size> 9 </Size>
<Diagonal> Off </Diagonal>
<Possible> Off </Possible>
<Reduce> Off </Reduce>
<Cell> <Row> 1 </Row><Col> 1 </Col><Value> 7 </Value> </Cell>
<Cell> <Row> 1 </Row><Col> 7 </Col><Value> 9 </Value> </Cell>
<Cell> <Row> 1 </Row><Col> 8 </Col><Value> 3 </Value> </Cell>
<Cell> <Row> 2 </Row><Col> 4 </Col><Value> 6 </Value> </Cell>
<Cell> <Row> 2 </Row><Col> 5 </Col><Value> 4 </Value> </Cell>
<Cell> <Row> 2 </Row><Col> 6 </Col><Value> 7 </Value><Stage> 2 </Stage> </Cell>
<Cell> <Row> 3 </Row><Col> 1 </Col><Value> 1 </Value> </Cell>
<Cell> <Row> 9 </Row><Col> 2 </Col><Value> 4 </Value> </Cell>
<Cell> <Row> 9 </Row><Col> 3 </Col><Value> 1 </Value> </Cell>
</Sudoku>
</XML>
[[code]]
==Reading Data==
Reading XML data is a little more work than writing it, but still not difficult. Since you wrote the file, you only need to be able to read what you wrote. [[toc]]
For this code segment, variable names with initial letter capitalized are assumed to have been declared global.
[[code format="lb"]]
sub FileLoad
filedialog "Load file...", FilePath$+"*.Sudoku", FullName$
call GetFileName$
if FileName$="" then notice "No file chosen!": end
open FullName$ for input as #File
FileOpen = True
call ProcessFile
end sub
sub GetFileName$
for pos = len(FullName$) to 1 step -1
if mid$(FullName$, pos, 1) = "\" then exit for
next pos
FileName$ = mid$(FullName$,pos+1)
FilePath$ = left$(FullName$,pos)
end sub
sub ProcessFile
do
call FindTag
select case Tag$
case "<XML>"
case "<Sudoku>":call InitCellArrays :call LoadPuzzle
case "</XML>" :close #File: FileOpen = False
end select
loop until FileOpen = False
end sub
sub LoadPuzzle
do
call FindTag
select case Tag$
case "<Cell>" :call LoadCell
case "<Diagonal>" :DiagActive = FindContentLogic()
case "</Diagonal>"
case "<Possible>" :PossibleShow = FindContentLogic()
case "</Possible>"
case "<Reduce>" :ReduceActive = FindContentLogic()
case "</Reduce>"
case "<Size>" :call CheckSize
case "</Size>"
case "</Sudoku>" :call ShowRefresh: exit sub
end select
loop until FileOpen = False
end sub
sub LoadCell
stage = 1
do
call FindTag
select case Tag$
case "<Row>" :row = FindContentValue()
case "</Row>"
case "<Col>" :col = FindContentValue()
case "</Col>"
case "<Value>" :val = FindContentValue()
case "</Value>"
case "<Stage>" :stage = FindContentValue()
case "</Stage>"
case "</Cell>" :CellValue(row,col) = val: CellStage(row,col) = stage
exit sub
end select
loop until FileOpen = False
end sub
sub LoadInputBuffer
if eof(#File) <> 0 then close #File: FileOpen = False: exit sub
do until (len(InputBuffer$) > 0 ) or (eof(#File) <> 0 ) 'skip blank lines
line input #File, InputBuffer$
loop
end sub
sub FindTag
if len(InputBuffer$) = 0 then call LoadInputBuffer
for i = 1 to len(InputBuffer$)
if mid$(InputBuffer$, i, 1) = "<" then exit for
next i
for j=i+1 to len(InputBuffer$)
if mid$(InputBuffer$, j, 1) = ">" then exit for
next j
Tag$ = mid$(InputBuffer$, i, j-i+1)
InputBuffer$ = mid$(InputBuffer$, j+1) 'remove tag
end sub
function FindContentString$()
for i = 1 to len(InputBuffer$)
if mid$(InputBuffer$, i, 1) = "<" then exit for
next i
FindContentString$ = trim$(mid$(InputBuffer$, 1, i-1))
InputBuffer$ = mid$(InputBuffer$, i) 'remove content
end function
function FindContentValue()
for i = 1 to len(InputBuffer$)
if mid$(InputBuffer$, i, 1) = "<" then exit for
next i
FindContentValue = val(mid$(InputBuffer$, 1, i-1))
InputBuffer$ = mid$(InputBuffer$, i) 'remove content
end function
function FindContentLogic()
FindContentLogic = False
if FindContentString$() = "on" then FindContentLogic = True
end function
[[code]]
[[toc]]
19 Mar 2014 17:18