On Tue, Nov 29, 2005 at 12:14:24PM -0800, Brent 'Dax' Royal-Gordon wrote: > Chip Salzenberg <[EMAIL PROTECTED]> wrote: > > P0 := P1 # aliasing: P0 and P1 point to same PMC > > P0 := opcode # aliasing: P0 points to PMC returned by opcode > > P0 = ... # assignment: modifies P0, NO MATTER WHAT '...' IS > > > > S0 := S1 # aliasing: S0 and S1 point to same header > > S0 := opcode # aliasing: S0 points to header returned by opcode > > S0 = ... # assignment: modifies S0, NO MATTER WHAT '...' IS > > > > I0 := ... # ILLEGAL > > I0 = ... # assignment: modifies I0 > > > > N0 := ... # ILLEGAL > > N0 = ... # assignment: modifies N0 > > I'm not sure about the last two (in a lot of ways, they're more like > := than = ),
I don't see that. The key semantic behind := is alias creation. After I0 = I1 # both old and new syntax is I0 an alias for I1? No. Does modifying I0 modify I1? No. Therefore, that's an '=', not a ':='. Meanwhile, after P0 = P1 # OLD SYNTAX changes to P0 are visible through P1. Thereofore, in the new scheme, that's a ':='. > I suppose that copying looks like: > S0 := copy S1 Yes, modulo the choice of the word "copy". I might call it "clone", which emphasizes that the return value has its own identity. -- Chip Salzenberg <[EMAIL PROTECTED]>
