Alternate version of memoized.jl

memoize.jl

macro memoize(ex)
    local f, u, g
    g = randstring(6)
    if isa(ex,Expr) && (ex.head == :function || ex.head == symbol("=")) &&
       !isempty(ex.args) && ex.args[1].head == :call && !isempty(ex.args[1].args)
        f = ex.args[1].args[1]
        ex.args[1].args[1] = u = symbol(string(f,"_unmemoized"))
    else
        error("@memoize must be applied to a method definition")
    end
    f_cache = esc(symbol(string(f,"_cache_$g")))
    quote
        $(esc(ex))
        const ($f_cache) = (Tuple=>Any)[]
        $(esc(f))(args...) = has(($f_cache),args) ?
           ($f_cache)[args] : (($f_cache)[args] = $(esc(u))(args...))
    end
end

macro unmemoize(ex)
    local f, u
    if isa(ex,Expr) && (ex.head == :function || ex.head == symbol("=")) &&
       !isempty(ex.args) && ex.args[1].head == :call && !isempty(ex.args[1].args)
        f = ex.args[1].args[1]
        ex.args[1].args[1] = u = symbol(string(f,"_unmemoized"))
    else
        error("@unmemoize must be applied to a method definition")
    end
    quote
        $(esc(ex))
        $(esc(f))(args...) = $(esc(u))(args...)
    end
end

macro memofixed(default, ex)
    local f, g
    g = randstring(6)
    if isa(ex,Expr) && (ex.head == :function || ex.head == symbol("=")) &&
        !isempty(ex.args) && ex.args[1].head == :call && !isempty(ex.args[1].args)
        f = ex.args[1].args[1]
        ex.args[1].args[1] = u = symbol(string(f,"_unmemoized"))
        eval(expr(:export, u))
    else
        error("@memofixed must be applied to a method definition")
    end
    f_cache = esc(symbol(string(f,"_cache_$g")))
    quote
        $(esc(ex))
        const ($f_cache) = (Tuple=>Any)[]
        function $(esc(f))(args...)
            if has(($f_cache),args)
                ($f_cache)[args]
            else
                ($f_cache)[args] = base_val = $(expr(:call, default, expr(:..., :args)))
                ret_val = $(esc(u))(args...)
                if ret_val != base_val
                    for i = 1:100
                        ($f_cache)[args] = base_val = ret_val
                        ret_val = $(esc(u))(args...)
                        if ret_val == base_val break end
                    end
                    if ret_val != base_val
                        error("Could not find fixed point of ",($f),"$args in 100 iterations of $u")
                    end
                end
                ret_val
            end
        end
    end
end