Meeting weekly 2011 12 20

Attending

Brian, Dave, Niko, Marijn

Status

• Marijn: static portion of type classes working; dynamic portion will probably be quite a bit of work
• Niko: unique closures: got distracted by some syntax work
• Niko: want to generalize the Ruby-like block shorthand to allow other kinds of functions, too; only works when unambiguous (always works in function calls)
• Brian: calling the syntax "block" doesn't make sense anymore then
• Niko: yeah, definitely should get the terminology right. maybe "stack closures" or something

Varieties of function

• Niko: I'd like to pare down the multiplicity of function types
• Marijn: get rid of bare functions?
• Niko: we currently have five varieties! native, bare, unique, stack, shared
• Niko: I was thinking about whether it's possible to eliminate bare
• Marijn: could just extract raw pointer in stdlib
• Niko: and conversely, a C function call_rust_closure
• Dave: what's native used for?
• Niko: ABI is different, but I'd like to eliminate it
• Brian: well, we have these wrappers
• Marijn: when you have a known direct call, just use the right ABI; otherwise auto-wrap
• Niko: that could complicate trans... or does LLVM inline the wrapper? that seems like the simplest
• Niko: same possibility for bare functions

Semicolons

• Marijn: Re: generalized blocks --- what about outside of call? syntax ambiguities?
• Niko: yeah, surprisingly hard. machinery for knowing at parse-time if you're in an "ignored-result" context, but you can't do that anymore; trying to push this logic into the typechecker
• Niko: my patch also eliminates significance of trailing semicolons
• Marijn: seems radical enough to be worth discussing on list
• Niko: I'll get it working and then send to the list
• Niko: could go whole-hog like Ocaml with the ignore thing
• Dave: yuck, way too strict

C stacks

• Marijn: do we have a way to call native functions without stack switch, if we know it will fit within the red zone?
• Niko: inclined to wait till we have data on perf --- it's yet another possibility to add crashes
• Brian: agreed
• Marijn: don't we need a lock to switch?
• Niko: no, it's pretty cheap. just some memory shuffling