Thank you all, you have given me much to think on here. I had versions that used a generic function as suggested, but I wasn't sure if the cognitive overhead in understanding the generic strategy outweighed the benefits to concision. I think it probably does in some cases, probably related to how difficult it is to develop a good name for the generic function. However, in this case, I'm on board. Thank you for your time. -Patrick <div class="gmail_quote">On 8 May 2012 09:23, Matthias Felleisen <<a href="mailto:matthias@ccs.neu.edu" target="_blank">matthias@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div class="HOEnZb"><div class="h5"> On May 7, 2012, at 5:41 PM, Patrick Mahoney wrote: > #| > Hello all, in a quest for greater concision, I'm looking for a way to abstract over the following code containing mostly definitions. Is there an accepted practice for abstraction over definition introduction?|# > > (define top-right-x > (lambda (a-grid-plane a-cell) > > ;;The next three definitions are what I am looking to abstract over, as they show up in many similarly defined functions.|# > (match-define (cell row-pos col-pos) a-cell) > > (define cell-size (grid-plane->cell-size a-grid-plane)) > > (match-define (size cell-w cell-h) cell-size) > > (+ cell-w > (* col-pos cell-w)))) > > (define top-right-y > (lambda (a-grid-plane a-cell) > > (match-define (cell row-pos col-pos) a-cell) > > (define cell-size (grid-plane->cell-size a-grid-plane)) > > (match-define (size cell-w cell-h) cell-size) > > (* row-pos cell-w))) > > #|How should I approach this? are my options parameters, leaving as is, a with- macro? </div></div>1. Define a higher-order function that computes these things: (define (vertical-horizontal body) (lambda (a-grid-plane a-cell) ... defines ... (body cell-w col-pos row-pos))) ;; you may need additional parameters (define top-right-x (vertical-horizontal (lambda (cell-w col-pos row-pos) (+ cell-w (* col-pos cell-w))) ... That's the best solution. 2. Define a macro for the entire function, not just the three auxiliaries. See 1, but perhaps less notation. 3. If the above is only a hint at how complex your definitions may get, read up on units. Units are modules abstracted over context, i.e., bundles over definitions abstracted over other definitions, possibly mutually recursive. -- Matthias </blockquote></div>