The idea is this - we use macros to make keyword arguments type-stable (note that it doesn't work yet):
@fastkw function f(x, y; a=1, b=2.0)
x+y+a+b
end
f(3,4) == 3 + 4 + 1 + 2.0
@fastcall f(3, 4; a = pi) == 3 + 4 + pi + 2.0This is a proof of concept of a design that can be applied at the lowering stage of Julia compilation, which creates and invokes a simple dispatch system that builds up a simple "named tuple" of (optional) keyword arguments.
The named tuple is created by a series of simple wrapper types KW{name}(value),
which can be constructed via the @kw macro (e.g. @kw(a=1)). The final tuple
looks like (@kw(a=b), @kw(b=2.0)) where the symbol names are sorted in-order
by the @fastkw and @fastcall macros for efficiency.