如何在Julia(多分派)中显示一个函数的所有方法?
例如,显示函数abs
在命名空间中存在的所有方法。
julia> methods(abs)
# 13 methods for generic function "abs":
[1] abs(a::Pkg.Resolve.FieldValue) in Pkg.Resolve at /home/david/pkg/julia-bin/julia-1.4.0-rc1/share/julia/stdlib/v1.4/Pkg/src/Resolve/fieldvalues.jl:61
[2] abs(a::Pkg.Resolve.VersionWeight) in Pkg.Resolve at /home/david/pkg/julia-bin/julia-1.4.0-rc1/share/julia/stdlib/v1.4/Pkg/src/Resolve/versionweights.jl:36
[3] abs(::Missing) in Base at missing.jl:100
[4] abs(x::Float64) in Base at float.jl:528
...
Dates
模块中定义的abs
方法:julia> methods(abs, Dates)
# 1 method for generic function "abs":
[1] abs(a::T) where T<:Dates.Period in Dates at /home/david/pkg/julia-bin/julia-1.4.0-rc1/share/julia/stdlib/v1.4/Dates/src/periods.jl:95