[Haskell-cafe] Haskell maximum stack depth

[Simon Peyton-Jones]

| > Yes, this is the standard solution, and it's a good one because it has a robust cost model (no quadratic
| costs).  However, it's tricky to get right; copying is simpler.  If a significant fraction of runtime (for some
| interesting program(s)) turned out to be consumed by copying stacks then we could consider this.
|
| Do you really need such evidence? If we agree that allowing stack to
| grow to arbitrary (limited only by memory availability) size is
| reasonable then surely we already know that there will be some stack
| size for which quadratic copying cost is going to get "stupid" :-)

Indeed, in principle.  But there are only so many GHC-HQ cycles.  Fixing stacks means not fixing something else, so it matters which issues bite most users.

This isn't a fixed-sum game.  The more people help fix and improve GHC, the more we can focus on the tricky bits that only we can do.

Simon