Listing the names of local variables

New to Julia
19

FWIW, this kind of functionality is often easier to implement than it looks. With MacroTools:

using MacroTools: prewalk
using MacroTools

# Your example:
expr = quote
    function readfile(filename::String)
   a = Dict{String,Int}()
   buf = ""
   open(filename,"r") do ios
      while(!eof(ios))
         bud = strip(readline(ios))
         items = split(buf,"")
         a[items[1]] = length(items)
      end
   end
   return a
end
end

# Gather all local variables
vars = []
prewalk(expr) do x
    @match x begin
        (lhs_Symbol = b_) => push!(vars, lhs)
        for var_Symbol in _ __ end => push!(vars, var)
        ((args__,) -> _) => push!(vars, [splitarg(a)[1] for a in args]...)
    end
    x
end
vars

returns [:a, :buf, :ios, :bud, :items]. It’s by no means a complete solution, but I don’t think you’d need that many more lines to find all local variables in every function in a file. Then if you gather all variable uses with a similar strategy, you can detect that :bud is never used, and emit a warning…

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