str for Julia

str.jl

function str(io::IOStream, x, n::Int, indent)
    T = typeof(x)
    print(io, T, " ")
    if isa(T, CompositeKind)
        println(io)
        if n > 0
            for field in T.names
                print(io, indent, "  ", field, ": ")
                str(io, getfield(x, field), n - 1, strcat(indent, "  "))
            end
        end
    else
        println(io, x)
    end
end
function str(io::IOStream, x::Array{Any}, n::Int, indent)
    println("Array($(eltype(x)),$(size(x)))")
    for i in 1:min(10, length(x))
        print(io, indent, "  ", i, ": ")
        str(io, x[i], n - 1, strcat(indent, "  "))
    end
end
str(io::IOStream, x::AbstractKind, n::Int, indent) = println(io, x)
str(io::IOStream, x::Symbol, n::Int, indent) = println(io, x)
str(io::IOStream, x::Function, n::Int, indent) = println(io, x)
str(io::IOStream, x::Array, n::Int, indent) = println(io, "Array($(eltype(x)),$(size(x)))", " ", x[1:min(4,length(x))])
str(io::IOStream, x) = str(io, x, 5, "")  # default is 5 levels
str(io::IOStream, x, n::Int) = str(io, x, n, "")
str(args...) = str(OUTPUT_STREAM::IOStream, args...)

str(io::IOStream, x::String, n::Int, indent) = println(io, typeof(x), " \"", x, "\"")
function str(io::IOStream, x::Dict, n::Int, indent)
    println("Dict", "[", length(x), "]")
    i = 1
    for (k,v) in x
        print(io, indent, "  ", k, ": ")
        str(io, v, n - 1, strcat(indent, "  "))
        if i > 10
            break
        end
        i += 1
    end
end


function istr(io::IOStream, x, n::Int, indent)
    T = typeof(x)
    print(io, T, " ")
    if isa(T, CompositeKind)
        println(io)
        if n > 0
            for field in T.names
                print(io, indent, "  ", field, ": ")
                istr(io, getfield(x, field), n - 1, strcat(indent, "  "))
            end
        end
    else
        println(io, x)
    end
end
function istr(io::IOStream, x::Array{Any}, n::Int, indent)
    println("Array($(eltype(x)),$(size(x)))")
    for i in 1:min(10, length(x))
        print(io, indent, "  ", i, ": ")
        istr(io, x[i], n - 1, strcat(indent, "  "))
    end
end
istr(io::IOStream, x::AbstractKind, n::Int, indent) = println(io, x)
istr(io::IOStream, x::Symbol, n::Int, indent) = println(io, x)
istr(io::IOStream, x::Function, n::Int, indent) = println(io, x)
istr(io::IOStream, x::Array, n::Int, indent) = println(io, "Array($(eltype(x)),$(size(x)))", " ", x[1:min(4,length(x))])
istr(io::IOStream, x) = istr(io, x, 5, "")  # default is 5 levels
istr(io::IOStream, x, n::Int) = istr(io, x, n, "")
istr(args...) = istr(OUTPUT_STREAM::IOStream, args...)

z_example_output.jl

julia> str(:(a+b*c))
Expr 
  head: call
  args: Array(Any,(3,))
    1: +
    2: a
    3: Expr 
      head: call
      args: Array(Any,(3,))
        1: *
        2: b
        3: c
      typ: Any
  typ: Any

julia> # Here's a Dict:

julia> str({:a => "hi", :b => 123, :c => [1,2,3], :d => {1, "asd", {:a => 1, :b => "bye"}}})
Dict[4]
  c: Array(Int64,(3,)) [1, 2, 3]
  a: ASCIIString "hi"
  b: Int64 123
  d: Array(Any,(3,))
    1: Int64 1
    2: ASCIIString "asd"
    3: Dict[2]
      a: Int64 1
      b: ASCIIString "bye"

julia> # The same, but showing the internal structure with istr:

julia> istr({:a => "hi", :b => 123, :c => [1,2,3], :d => {1, "asd", {:a => 1, :b => "bye"}}})
Dict{Symbol,Any} 
  keys: Array(Any,(16,))
    1: c
    2: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    3: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    4: a
    5: b
    6: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    7: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    8: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    9: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    10: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
  vals: Array(Any,(16,))
    1: Array(Int64,(3,)) [1, 2, 3]
    2: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    3: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    4: ASCIIString 
      data: Array(Uint8,(2,)) [0x68, 0x69]
    5: Int64 123
    6: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    7: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    8: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    9: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
    10: __c782dbf1cf4d6a2e5e3865d7e95634f2e09b5902__
  ndel: Int64 0
  deleter: identity

julia> 

This is a version of R's str function for Julia. It shows the structure of an object. Two versions are included. One is str that's designed to show the "user-facing" structure. The other is istr for "internal structure". It is meant to show the raw object contents. For example, str and istr show Dict's differently. Also, for arrays, I provide a method to display each cell of an Array{Any}, because that's often used as a generic container. Other arrays are just shown on one line.