https://github.com/juliafunctional/fixfunctionargument.jl

Fix a function positional argument to a callable. Replacement for `Base.Fix`.
https://github.com/juliafunctional/fixfunctionargument.jl

partial-application partial-apply

Last synced: 4 months ago
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Fix a function positional argument to a callable. Replacement for `Base.Fix`.

• Host: GitHub
• URL: https://github.com/juliafunctional/fixfunctionargument.jl
• Owner: JuliaFunctional
• License: mit
• Created: 2025-09-19T15:01:02.000Z (5 months ago)
• Default Branch: main
• Last Pushed: 2025-09-19T15:47:14.000Z (5 months ago)
• Last Synced: 2025-09-19T17:41:50.337Z (5 months ago)
• Topics: partial-application, partial-apply
• Language: Julia
• Homepage:
• Size: 11.7 KB
• Stars: 1
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# FixFunctionArgument

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A Julia package for fixing a given positional argument to a given callable. Intended as a straight improvement upon and stand-in replacement for `Base.Fix` (including `Base.Fix1` and `Base.Fix2`).

## Provided functionality

The package exports the following bindings:

* `Fix`

* `Fix1`

* `Fix2`

The usage is the same as with the `Base` counterparts.

## Motivation

`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-repl

julia> sizeof(Base.Fix1(convert, Float32))

8

julia> using FixFunctionArgument

julia> sizeof(Fix1(convert, Float32))

0

```

Here is a more concrete, albeit artificial, example of a performance difference between `Fix` and `Base.Fix`.

```julia

# calls `f` eight times

function iterated_function_8(f::Func, x) where {Func}

    f = f ∘ f

    f = f ∘ f

    f = f ∘ f

    f(x)

end

# like `identity`, but should not inline

@noinline function identity_noinline(x)

    x

end

# only does calling, for benchmarking call/stack overhead

function identity_noinline_iterated(x)

    iterated_function_8(identity_noinline, x)

end

using BenchmarkTools, FixFunctionArgument

x = Fix1(convert, Float32)

y = Base.Fix1(convert, Float32)

@btime identity_noinline_iterated($x)     #  1.292 ns (0 allocations: 0 bytes)

@btime identity_noinline_iterated($y)     # 16.222 ns (1 allocation: 16 bytes)

@code_typed identity_noinline_iterated(x)  # shows that the entire call gets constant folded away

```

Interpretation: for `Fix`, unlike for `Base.Fix`, the `identity_noinline_iterated` call has zero cost, because the entire call gets constant folded away.