Example macro to allow embedding JSON style data structures into Julia dev-v0.4

julia_json_data_macro

# Tested on VERSION => v"0.4.0-dev+5879"
macro data(data) _json(data) end
macro json(data) _json(data) end

function _json(data::Any)
    data
end

function _json(data::Expr)
    if data.head === :cell1d
        Expr(:call, :Dict, map(_json, data.args)...)
    elseif data.head === :(:)
        Expr(symbol("=>"), map(_json, data.args)...)
    elseif data.head === :vect 
        Expr(data.head, map(_json, data.args)...)
    elseif data.head === :curly && data.args[1] in [:json, :_, :j, :d]
        Expr(:call, :Dict, map(_json, data.args[2:end])...)
    else
        throw("Unknown type: $data")
    end
end

# syntax deprecation warning
@json { "a": 1, "b": 2 } 

# Without syntax warnings by using type-prefix syntax
@data json{ "a": 1, "b": [3,4] } 
@data json{ "a": 1, "b": "b": [3, d{"d": 1, "b": "b"}] } # note the "d" prefix on the inner dict

# Tests
@assert Dict("a"=>1, "b"=>2) == @json { "a": 1, "b": 2 } 
@assert Dict(Dict("a"=>1, "b"=> [3, Dict("d"=>1, "b"=>"b")])) == @show( @data d{ "a": 1, "b": [3, d{"d": 1, "b": "b"}] })
@assert Dict("a"=>1, "b"=> [3,4]) == @data json{ "a": 1, "b": [3,4] }