[racket] read of numbers with decimal point default to exact?

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Fri Jul 23 10:19:57 EDT 2010

On Jul 23, 2010, at 8:40 AM, Neil Van Dyke wrote:

> To support programmers who want to use exact numbers by default, such as some financial programmers, without making that the default for Racket, let's say we define a new Racket variant for these programmers ("#lang numbers-racket", heh).  In this case, I'm wondering whether there is a problem with any Racket *libraries* confusing these programmers when the numbers they get out of the libraries can quietly become inexact.  Perhaps the solution here is simply that authors of numerical libraries should provide multiple two versions of certain of operations: a version that preserves exactness, and a version that is fast?

I have been thinking about this issue a bit for the SEC issue (Python for waterfall finance models). This may indeed require a different library interaction, possibly with coercions inserted that express interval guarantees. Let's put it on our list of things to discuss -- Matthias

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