11/28/2002

Have a look at Abacus:
http://www-cad.eecs.berkeley.edu/HomePages/aml/abacus/abacus.html

[HJG] 2005-12-26: "resource was not found"

KHT 2005-12-26:  Current link seems to be: http://tahoe.inesc.pt/~aml/abacus/abacus.html

Also note the [tcllib] package [matrix].

-----
I've been thinking about writing a very simple spreadsheet in tcl for a few weeks now.  
It would store its data in [[array get]] format with cells named in the R1C1 style.  
The main issue is that I wanted a '''much''' more flexable expr command.  
I thought through various preprocesing schemes to use before calling expr 
to evaluate the contents of a cell, then I found this handy patch [http://www.elf.org/etc/tcl-expr-patch.html].  
I ported it  to 8.4.0 [http://cfa-www.harvard.edu/~john/tcl8.4.0-expr.patch]. 
You either like this or you don't.

Cell reference expansion is done with regsub, while the patched core allows procs to be used in expr.
Literal cell values are stored in the Sheet array. 
Displayed cell values (evaluated) are cached in the Cells array.  
This could be used with the tkTable widget or a simple array of entrys.  
I'm going to try to work out the refering and referenced cell sets for each cell 
and detect circular references next. 

[John Roll]

----
 array set Sheet {
        R1C1    { 3 }
        R1C2    { 5 + 4 }
        R1C3    R1C4
        R1C4    -6
        R1C5    { min(4, R1C3) }
        R1C6    { "TTText" }
        R2C7    { sum(R1C1:R1C2, 100, R1C1:R1C2, 5) }
 }

 proc min { a b } {
        return [expr $a < $b ? $a : $b]
 }

 proc sum { args } {
    return [substexpr [join [join $args] +]]
 }

 proc range { r1 c1 rn cn } {
        set list {}
        for { set r $r1 } { $r <= $rn } { incr r } {
        for { set c $c1 } { $c <= $cn } { incr c } {
                lappend list R${r}C${c}
        } }

        return $list
 }

 proc substexpr { cell } {
        global Cells

        regsub -all -- {R([0-9]+)C([0-9]+):R([0-9]+)C([0-9]+)} $cell    \
               {range(\1, \2, \3, \4)} code
        regsub -all -- {(R[0-9]+C[0-9]+)} $code {$Cells(\1)} code

        if { [catch { set result [expr $code] } reply] } { puts $reply }

        return $result
 }

 proc Sheet { name indx op } {
        global Sheet
        global Cells

        if { [catch { set val $Sheet($indx) } reply] } {
                set Cells($indx) 0
                return
        }
 }

 proc Cells { name indx op } {
        global Cells
        global Sheet

    if { ![catch { set val $Cells($indx) } reply] } {
        return
    }

    if { [catch { set Cells($indx) [substexpr $Sheet($indx)] }] } {
        set Cells($indx) 0
    }
 }

 array set Cells {}
 catch {console show}

 trace variable Cells r Cells
 trace variable Sheet r Sheet

 foreach cell [array names Sheet] {
        puts "$cell = $Cells($cell)"
 }
----
[Category Application] - [Category GUI]