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*To*: lucier@xxxxxxxxxxxxxxx*Subject*: Re: linear -> affine and shapes are immutable*From*: Jussi Piitulainen <jpiitula@xxxxxxxxxxxxxxxx>*Date*: 13 Nov 2001 09:22:05 +0200*Cc*: srfi-25@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*Delivered-to*: srfi-25@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*In-reply-to*: lucier@xxxxxxxxxxxxxxx's message of "Mon, 12 Nov 2001 18:26:30 -0500 (EST)"*References*: <200111122326.fACNQUX12643@xxxxxxxxxxxxxxxxxxxxxx>*Sender*: jpiitula@xxxxxxxxxxxxxxxx

lucier@xxxxxxxxxxxxxxx writes: > I would suggest that "affine" would be a better name than > "linear" for the properties of the access functions. Linear > is OK (as in linear as opposed to quadratic polynomials), but in > this context with all the "vector"s and "array"s, I think affine > would be better. Interesting. A book on Java 2D graphics defines affine transformation as "one in which parallel lines are still parallel after ...". I cannot judge which is better. I don't want to put in anything about parallel lines. Does "each index is a sum of multiples" match "affine" at least as well as it matches "linear"? > Also, instead of saying > > It is an error to store anything in an element of a shape. > > can one just say that "Shapes are immutable"? We might indeed want to specify the latter. It is not so now: any array of the right form can be used as a shape, `make-array' just stores it into the new record, the _shape_ remains happily mutable - it is only the array that breaks horribly if you mutate its shape. Choices are to specify that `array-shape' returns an immutable array (copy if needed) or to leave it as an implementation quality issue. -- Jussi

**Follow-Ups**:**Re: linear -> affine and shapes are immutable***From:*Brad Lucier

**References**:**linear -> affine and shapes are immutable***From:*lucier

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