On Sat, 28 Nov 2009, Frank Barknecht wrote:
I encountered this in the SICP as well which is from 1984, so probably knows its Smalltalk as well, although the index only mentions Smalltalk once in a footnote. Here's the intro to selectors: http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-14.html#%_idx_1290
This is not the same meaning of selector. We have to be careful about that. In mainstream OO vocabulary, this would be called «reader», «getter», or «accessor» (or half of an accessor), although in your example, they define these as plain functions because there is no OO in Scheme.
In Scheme, the concept of selector we are talking about does not exist. In CommonLISP, it would be called «the symbol of a generic-function» because when CommonLISP integrated the notion of OO it turned it quite inside-out.
I don't know about other OOP frameworks for LISP and Scheme but you can assume that there are as many as there are for Tcl. In those systems you may find a more ordinary concept of selector. Or not.
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