Splitting the Splitter

Here’s a cute little oafish trick that has helped me out more than a few times.  You run an inline Split/Array operation to mimic what the LISP cdr and cadr, etc. functions do, which is to pick out a logical subordinate within a string construct which represents a paired list (logically speaking).

myString = “1=Apple,2=Banana,3=Cherry,4=Grapes”

item2 = Split(Split(myString, “,”)(1), “=”)(1)

This will return “Banana”.  You can continue nesting (or un-nesting, if you will) obviously, but without error checking this can become quite dangerous.  But it is nice to see a use for something like this.  Now, if only there were a simple, easy way to mimic mapcar and apply as well.

Now vs Now: VBScript and KiXtart

Date values are a very common aspect to script writing and most any programming situation in general.  How dates are stored, presented and manipulated varies widely from one programming language to another.

Let’s look at the “Now” function included with Windows Scripting Host’s VBScript.  This function returns the current date and time in “mM/dD/YYYY hH:MM:SS XM” format.

In case you’re wondering what the hell “mM” and “hH” imply: they imply zero-trim numbers.  In other words 8:01:42 AM is not stored as 08:01:42 AM. The leading zero is omitted.  Same for month (“mM”), and day (“dD”) as well.

But KiXtart, one of my all-time favorite scripting languages, handles date values quite differently.  At first it may seem almost identical, but as you pick things apart you start to see the deltas.

(kixtart)
? @date+" "+@time
>> 2010/03/02 08:20:01

(vbscript)
Wscript.echo Now
>> 3/2/2010 8:20:01 AM

When you compare the output of each result above, not only are the order of YYYY/MM/DD flipped from M/D/YYYY, but the zero-trim is not used with KiXtart.  Is this “bad” or “wrong”?  No.  Just different.  There are times when this is actually a very handy benefit to have as the default.  But also notice that the time stamp is formatted differently.  And the AM/PM suffix is not shown.

So, how can we make KiXtart do it the way VBScript does it?  This is assuming you need to make it do that, of course, which you may not.  But this is for demonstration purposes, so cut me some slack - if you will.

Below are two examples for producing a VBScript formatted “Now” result.  The first one uses a rudimentary date->string parsing technique.  The second does a cop-out and simply knocks on the door of the ScriptControl COM interface to make VBScript do the work and hand back a result.  The performance overhead is about the same at this scalar load level.  If you start piling in a lot more, the results can shift the balance of performance in either direction, depending upon the nature of what your doing (math, string, date, or object management tasks).

------------------------------------------------
Break ON

Function Now1()
    $today = ""+@monthno+"/"+@mdayno+"/"+@year
    $arrTime = Split(@time, ":")
    $hour = $arrTime[0]
    $min  = $arrTime[1]
    $sec  = $arrTime[2]
    If Int($hour) < 12
        $sfx = "AM"
    Else
        $sfx = "PM"
    EndIf
    $Now1 = $today+" "+Int($hour)+":"+$min+":"+$sec+" "+$sfx
EndFunction

Function Now2()
    Dim $sc, $result
    $sc = CreateObject("ScriptControl")
    $sc.Language = "vbscript"
    $result = $sc.Eval('Now()')
    $sc = 0
    $Now2 = $result
EndFunction

? "Kix: "+Now1()
? "VBs: "+Now2()

The results should be identical.  Could I/you refactor the Now1() function to nest statements and further compact the code?  Sure.  Does it buy any performance gains? Not really.

Consider this variation…

Function Now1()
    $today = ""+@monthno+"/"+@mdayno+"/"+@year
    $arrTime = Split(@time, ":")
    If Int($arrTime[0]) < 12
        $Now1 = $today+" "+Int($arrTime[0])+":"+$arrTime[1]+":"+
            $arrTime[2]+" AM”
    Else
        $Now1 = $today+" "+Int($arrTime[0])+":"+$arrTime[1]+":"+
            $arrTime[2]+" PM”
    EndIf
EndFunction

More compact for sure.  But there’s a hidden, even if trivial price: The repeated use of an array index request.  There are other ways to compact/refactor this of course, but for such few lines of code the pay-offs are difficult to justify beyond elegant coding form (aesthetics).  Oh well, blah blah blah.  What do I know anyway.  I just finished a huge “breakfast-for-dinner” and was then told my car repairs would cost way too much, so I’m blabbering to let off steam.  I hope you enjoyed this.

Poor Mans Nested Array Splitting

Some will laugh.  Some will scoff.  Some will snort and then realize they accidentally blew a booger on their shirt and say “oh damn”.  Oh well, here goes…

<%
Const myList = "1=RED,2=YELLOW,3=GREEN,4=CYAN,5=BLUE,6=MAGENTA"

Sub ColorNumList(default)
    For each pair in Split(myList, ",")
        x = Split(pair, "=")
        If Cstr(default) = x(0) Then
            Response.Write "<option value=" & x(0) & _
            " selected>" & x(1) & "</option>"
        Else
            Response.Write "<option value=" & x(0) & _
            ">" & x(1) & "</option>"
        End If
    Next
End Sub
%>

To use this, you simply insert it within a matching set of ASP code tags inside of a <select></select> form object tag set:

...
<select name="colornum" size="1">
    <% ColorNumList 3 %>
</select>
...

KiXtart: Array List Sorting

Function ArrayList()
    ; this code creates and populates an ArrayList
    ? "Example: ArrayList object"
    $myArrayList = CreateObject("System.Collections.ArrayList")
    $=$myArrayList.Add("Dog")
    $=$myArrayList.Add("Chicken")
    $=$myArrayList.Add("Rooster")
    $=$myArrayList.Add("Hen")

    ; Now, to add an element and sort the ArrayList, all we need to do is:

    ; [1] add the new element to the ArrayList
    $=$myArrayList.Add("Pig")
    ; [2] sort the ArrayList
    $=$myArrayList.Sort()
    For each $item in $myArrayList
        ? $item
    Next
EndFunction

$x = ArrayList()

VBScript / ASP Array_Slice Function

Almost as good as the PHP function Array_Slice()

Function Array_Slice(arr, start, newArray)
 Dim x : x = 0
 For i = start-1 to Ubound(arr)-1
  ReDim Preserve newArray(x)
  newArray(x) = arr(i)
  x = x + 1
 Next
 Array_Slice = Ubound(newArray)
End Function