Re: [TCLCORE] TIP #363: Vector Math in the Tcl Core

[Neil M. <ne...@Cs...>]

Alexandre Ferrieux wrote:
> On 3/4/10, Karl C. Hansen <Kar...@br...> wrote:
>>   TIP #363: VECTOR MATH IN THE TCL CORE
>>  =======================================
>>
>>   With the proposed enhancement, and a vector-math core enhancement,
>>   given the assignments above, the following would behave identically:
>>
>>    expr $ListA + {4 5 6}
>>    expr $ListA + $ListB
>>    expr {1 2 3} + $ListB
>>    expr {1 2 3} + {4 5 6}
> 
> So basically you're proposing to break just about everything in Tcl
> parsing to avoid writing a simple proc for vector/matrix/tensor
> computations ?
> 
>     proc myexpr {x op y} {
>       if {[llength $x]==1} {return [expr $x $op $b}
>       if {[llength $x]!=[llength $y]} {error "Dimension mismatch"}
>       set z {}
>       foreach a $x b $y {lappend z [myexpr $a $op $b]}
>       return $z
>     }
> 
>    # The following four do the same today without breaking anything:
>    myexpr $ListA + {4 5 6}
>    myexpr $ListA + $ListB
>    myexpr {1 2 3} + $ListB
>    myexpr {1 2 3} + {4 5 6}

Or just Brace Your Exprs (TM) and then write a TIP which actually 
proposes what the title suggests: adding vector versions of operators to 
[expr], such that [expr {$ListA + {4 5 6}}] does what makes sense.

-- Neil