path.jl

@unix_only begin
    const path_separator       = "/"
    const path_separator_regex = r"/+"
    const path_absolute_regex  = r"^/"
    const path_parse_regex     = r"^(.*?/|)([^/]+?)(\.[^\.]+|)$"

    splitdrive(path::String) = ("",path)
end
@windows_only begin
    const path_separator       = "\\"
    const path_separator_regex = r"[/\\]+"
    const path_absolute_regex  = r"^(?:\w+:)?[/\\]"
    const path_parse_regex     = r"^(.*?[/\\]|)([^/\\]+?)(\.[^\.]+|)$"

    function splitdrive(path::String)
        # TODO: split out network drives?
        m = match(r"^(\w+:|)(.*)$", path)
        m.captures[1], m.captures[2]
    end
end

isabspath(path::String) = ismatch(path_absolute_regex, path)

joinpath(a::String) = a
joinpath(a::String, b::String, c::String...) = joinpath(joinpath(a,b), c...)
joinpath(a::String, b::String) = isempty(a) || isabspath(b) ? b :
    ismatch(path_separator_regex, a[thisind(a,end):end]) ?
        strcat(a,b) : strcat(a,path_separator,b)

function parsepath(path::String)
    m = match(path_parse_regex, path)
    m != nothing ? (m.captures[2], m.captures[3], m.captures[4]) : (path, "", "")
end

function normpath(path::String)
    isabs = isabspath(path)
    drive, path = splitdrive(path)
    parts = split(path, path_separator_regex)
    # isdir = ismatch(r"^\.{0,2}$", parts[end])
    parts = filter(x->!isempty(x) && x!=".", parts)
    while true
        clean = true
        for j = 1:length(parts)-1
            if parts[j] != ".." && parts[j+1] == ".."
                del(parts, j:j+1)
                clean = false
                break
            end
        end
        clean && break
    end
    if isabs
        while isabs && !isempty(parts) && parts[1] == ".."
            shift(parts)
        end
    elseif isempty(parts)
        push(parts, ".")
    end
    path = join(parts, path_separator)
    if isabs
        path = strcat(path_separator, path)
    end
    # if isdir && !isempty(parts) && !ismatch(r"^\.{0,2}$", parts[end])
    #     path = strcat(path, path_separator)
    # end
    strcat(drive,path)
end
normpath(a::String, b::String...) = normpath(joinpath(a,b...))

abspath(path::String) = normpath(isabspath(path) ? path : joinpath(pwd(),path))

function realpath(path::String)
    path = tilde_expand(path)
    sp = ccall(:realpath, Ptr{Uint8}, (Ptr{Uint8}, Ptr{Uint8}), path, C_NULL)
    system_error(:realpath, sp != C_NULL)
    s = bytestring(sp)
    c_free(sp)
    return s
end

Just a small question: why the removal of the isdir check? Performance? Compatibility with ThatOtherOS? Originally, I introduced it so that paths like /dir1/dir2/filename/. or /dir1/dir2/filename/anything/.. are not resolved to /dir1/dir2/filename, i.e. they don't yield a valid file name, which seems wrong (and bug-prone) to me.

(I was referring to normpath of course.)