pgfmacro.jl

using MacroTools, Lazy
import MacroTools: prewalk

using DataStructures

function prockey(key)
  (isa(key, Symbol) || isa(key, String)) && return :($(string(key)) => nothing)
  @capture(key, (a_:b_) | (a_=>b_) | (a_=b_)) || error("Invalid pgf option $key")
  isa(a, Symbol) && (a = Expr(:quote, a))
  :($a=>$b)
end

function procmap(d)
  @capture(d, {xs__}) || return d
  :(OrderedDict{Any, Any}($(map(prockey, xs)...)))
end

macro pgf(ex)
  @>> ex prewalk(procmap) esc
end