A Julia package for fixing a given positional argument to a given callable. Intended as a straight improvement upon and stand-in replacement forBase.Fix (includingBase.Fix1 andBase.Fix2).
The package exports the following bindings:
The usage is the same as with theBase counterparts.
Base.Fix fails to be a zero-cost abstraction when the provided callable or the provided argument to fix are types.Fix handles that case as expected:
julia>sizeof(Base.Fix1(convert, Float32))8julia>using FixFunctionArgumentjulia>sizeof(Fix1(convert, Float32))0
Here is a more concrete, albeit artificial, example of a performance difference betweenFix andBase.Fix.
# calls `f` eight timesfunctioniterated_function_8(f::Func, x)where {Func} f= f∘ f f= f∘ f f= f∘ ff(x)end# like `identity`, but should not inline@noinlinefunctionidentity_noinline(x) xend# only does calling, for benchmarking call/stack overheadfunctionidentity_noinline_iterated(x)iterated_function_8(identity_noinline, x)endusing BenchmarkTools, FixFunctionArgumentx=Fix1(convert, Float32)y= Base.Fix1(convert, Float32)@btimeidentity_noinline_iterated($x)# 1.292 ns (0 allocations: 0 bytes)@btimeidentity_noinline_iterated($y)# 16.222 ns (1 allocation: 16 bytes)@code_typedidentity_noinline_iterated(x)# shows that the entire call gets constant folded awayInterpretation: forFix, unlike forBase.Fix, theidentity_noinline_iterated call has zero cost, because the entire call gets constant folded away.
