toivoh

# union of immutable types not to freeze/unfreeze
typealias NoFreeze Union(Number, String)

type Frozen{T,COUNT}
    item::T
    watchers::Set{WeakRef}
end

typealias FrozenArray{T,N,COUNT} Frozen{Array{T,N},COUNT}

toivoh

# ---- ObjNode: capture of an object's output to show() -----------------------

type ObjNode
    # actual capture
    obj
    reused::Bool
    items::Vector   # ObjNode:s and strings/chars

    # scratch space for recshow etc
    strlen::Integer

toivoh

require("recshow.jl")

type T
    x
    y
end

type Unshowable; end
show(io::IO, x::Unshowable) = error("Tried to show Unshowable()")

toivoh

code = quote
    function show_body_lines(io::IO, ex)
        args = is_expr(ex, :block) ? ex.args : {ex}
        for arg in args
            if !is_linenumber(arg); print(io, '\n'); end
            show(io, arg)
        end
    end
end

toivoh

macro expect(pred)
    :( ($esc(pred)) ? nothing : error($"error: expected $pred == true") )
end

is_expr(ex, head::Symbol) = (isa(ex, Expr) && (ex.head == head))

function split_fdef(fdef::Expr)
    @expect (fdef.head == :function) || (fdef.head == :(=))
    @expect length(fdef.args) == 2
    signature, body = tuple(fdef.args...)

toivoh

show_sexpr(ex) = show_sexpr(OUTPUT_STREAM, ex)
show_sexpr(io::IO, ex) = show_sexpr(io, ex, 0)
show_sexpr(io::IO, ex, indent::Int) = show(io, ex)

const sexpr_indent_width = 2

function show_sexpr(io::IO, ex::Expr, indent::Int)
    inner = indent + sexpr_indent_width
    if (ex.head === :block) inter, post = ("\n"*" "^inner, "\n"*" "^indent)
    else                    inter, post = (" ", "")

toivoh

# ---- @sexpr: S-expression to AST conversion ----

is_expr(ex, head::Symbol) = (isa(ex, Expr) && (ex.head == head))
is_expr(ex, head::Symbol, n::Int) = is_expr(ex, head) && length(ex.args) == n

macro sexpr(ex)
    esc(sexpr_to_expr(ex))
end

sexpr_to_expr(ex) = expr(:quote, ex)

toivoh

is_expr(ex, head::Symbol) = (isa(ex, Expr) && (ex.head == head))
is_expr(ex, head::Symbol, n::Int) = is_expr(ex, head) && length(ex.args) == n

# simple syntax version
macro get!(d, k, default)
    quote
        d, k = $(esc(d)), $(esc(k))
        has(d, k) ? d[k] : (d[k] = $(esc(default)))
    end
end

toivoh

   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" to list help topics
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.0.0+105549818.rb65f
 _/ |\__'_|_|_|\__'_|  |  Commit b65f0478b4 (2012-12-26 20:02:44)
|__/                   |

julia> include("test_show_dispatch.jl")
type error: subtype: expected Type{T<:Top}, got (CompositeKind,{:i0, Int64, #undef, #undef, #undef  …  :vals, Array{Any,1}, :#s176, Int64})

toivoh

#    Copyright (c) 2014: Toivo Henningsson
#
#    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
#
#    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
#
#    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WIT