How to get variable names inside a function in julia-CodePudding

For example

function f(x)
    # do something
    # then I assigned the outside variable name of 'x' to y
    println(y)
end

f(1)

I will get

# something and
1

then,

a = 1
f(a)

I will get

# something and
"a"

Is it possible in julia? If not, how can I get my function operation log?

CodePudding user response：

Depending on what you need a simples macro that dumps function calls that still get executed could be:

macro logs(expr)
    @info expr
    expr
end

And this can be used as:

julia> a = π/2;

julia> @logs sin(a)
[ Info: sin(a)
1.0

CodePudding user response：

The most idiomatic way would be to slightly change your interface of f and require a keyword argument:

julia> function f(;kwargs...)
           for (k, v) in kwargs
               println("$k = $v")
           end
       end
f (generic function with 1 method)

julia> f(a = 1)
a = 1

Alternatively (short of inspecting stack traces), you need something macro-based:

julia> struct Quot
           expr
           value
         end

julia> macro quot(e)
           return :($Quot($(QuoteNode(e)), $e))
       end
@quot (macro with 1 method)

julia> function f2(x::Quot)
           println(x)
       end
f2 (generic function with 1 method)

julia> x = 2
2

julia> f2(@quot x)
Quot(:x, 2)