Vector operations in SKILL

Hi,

geGetSelSet() does not return an array of points, it returns a list (technically a singly linked list) of the currently selected figures. A "figure" in turn has a bounding box that is defined in terms of a lower left and an upper right point.If you want for example the x-coordinates of the lower left points of all selected figures you need to go like this:

(mapcar (lambda (bBox) (xCoord (lowerLeft bBox))) (geGetSelSet)~>bBox)

SKILL does support arrays though - for example

(declare vector[100])

creates an array (named vector) with one 100 elements which provides true random access to it's elements in terms of an index. It is important to understand the difference between lists and arrays, like I said a list in SKILL is a linked list where each element has a pointer to the next element in the list. So to get to an element somewhere in the middle you need to iterate over the list element by element - this can slow down the performance of a SKILL script if you deal with very long lists.

To follow on from what Max said, SKILL is a LISP which means it has numerous functions for processing lists - for example mapping functions to transform lists.

So for example, if you want to find the xCoord of all selected origins:

mapcar('xCoord geGetSelSet()~>xy)

If you had two lists of numbers, and wanted to add the corresponding number of each list together you could do:

mapcar('plus listA listB)

The idea is that mapcar iterates over the list(s) and then calls the function given as the first argument with the corresponding element of each list (one or more lists). If there is one list, it passes one argument to the function; if there were 10 lists, it would pass 10 arguments and so on.

There are several other mapping functions which do various other types of processing (e.g. map, mapc, mapcar, mapcan, maplist - and a few others).

Note that the function passed as the first argument can either be a named function, or a function object created on the fly (Max used lambda to create an anonymous function). 

There's also a convenience form, that you can do (using Max's example):

xCoords=foreach(mapcar bBox geGetSelSet()~>bBox
  xCoord(lowerLeft(bBox))
)

This is equivalent - the foreach form takes the argument list from the argument after the mapping function name, and the body from within the foreach to produce an anonymous function:

So it's not really a matter of SKILL keeping up with the times here - these have always existed in SKILL. Sure it's different from Python, but then again all languages are different. In fact Python has a number of concepts which have been inspired by LISP - and we have (here and there) added features to SKILL which were inspired by Python!

Andrew

Thank you! Will definitely help me out.

Is there a marketplace where one can find SKILL-code freelancers?