If it were me I would patch a parser that did several passes iteratively instead of recursively:
1) Check for unbalanced parens, and count nesting depth 2) Pass all parts of the list unchanged, except those constitute a max depth expression, which are evaluated and substituted 3) Repeat 2 until the entire expression is reduced Order of operations is a bit harder, but you could do that with multiple passes too. On Mon, Nov 9, 2015 at 9:13 AM, Liam Goodacre <liamg...@hotmail.com> wrote: > I'm trying to make a patch which can simplify arithmetic expressions given > as a single message. I want to, for example, send it the message "( 2 + 5 > )" and get "7", or send it "foo ( 8 / 4 )" and get "foo 2". This much I > have achieved, using [list-drip] and [route] to identify the data inside > brackets, and [list-reduce] to perform the arithmetic. The difficulty I'm > having is in getting it to work recursively, so that eg. "bar ( 5 - ( 3 - 2 > ) )" gives "bar 1". Ideally, the abstraction would be able to process any > number of bracket-levels, just as a scientific calculator does. > > I know that programming recursively on PD is not for the faint hearted, > and I feel pretty much out of my depth. If anyone can point me in the right > direction, I will be most grateful. Alternatively, if it turns out to be > too hard, I'll settle for what I've made already. > > I'm attaching the patch, although I think it's pretty far removed from > what the solution will look like. Note that I'm using Zexy and list-abs > here. > > _______________________________________________ > Pd-list@lists.iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list > >
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