Macro: extract the method name, arguments and the body

General Usage
1

There are two syntaxes that I know that defines a function:

julia> Meta.@dump function f(x)
       x
       end
Expr
  head: Symbol function
  args: Array{Any}((2,))
    1: Expr
      head: Symbol call
      args: Array{Any}((2,))
        1: Symbol f
        2: Symbol x
    2: Expr
      head: Symbol block
      args: Array{Any}((3,))
        1: LineNumberNode
          line: Int64 1
          file: Symbol REPL[42]
        2: LineNumberNode
          line: Int64 2
          file: Symbol REPL[42]
        3: Symbol x

julia> Meta.@dump f(x)=x
Expr
  head: Symbol =
  args: Array{Any}((2,))
    1: Expr
      head: Symbol call
      args: Array{Any}((2,))
        1: Symbol f
        2: Symbol x
    2: Expr
      head: Symbol block
      args: Array{Any}((2,))
        1: LineNumberNode
          line: Int64 1
          file: Symbol REPL[43]
        2: Symbol x

when there is a where statement things just get more complicated. It’s common for a macro to take a function and manipulate its name, arguments and body. Is there a built-in method that extracts those information?

Further, when I use a macro before a function definition, the macro gets a collection of expressions. How do I merge them like how Meta.@dump does?

2

My solution for the second problem is

macro mymacro(expr...)
    mymacro(Meta.@dump(expr...))
end
3

Probably not exactly the answer to your questions, but MacroTools.jl provide some useful, well, macro tools. You can convert (normalize) function definitions to short or long form, among other things.

3 Likes
4

Just found ExprTools.jl that does the job.