[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

name an array function

From: Daniel Llorens
Subject: name an array function
Date: Mon, 21 Nov 2016 11:32:28 +0100


version 2.2 of Guile will (I hope) include rank-polymorphic versions of 
array-ref, array-set! and array-for-each. What this means is that instead of 
requiring as many indices as the rank of the array, with these functions you 
can give fewer indices and get a subarray (a ‘prefix slice’). If you give all 
the indices, they behave just as the current versions.

My original intention was for these functions to replace array-ref and 
array-set!. That's how a number of array languages/libraries do it (numpy, to 
mention a popular one. You don't need to say A[i, :, :], you can just say 
A[i].). However, the maintainers spoke against this, so these functions need 
different names.

The names I chose are array-from, array-amend! and array-for-each-cell. These 
names are taken from the J docs 
(,, because the behavior is 
based on J and I consider J to be ‘the source’ when it comes to these concepts.

civodul has proposed array-slice instead of array-from. However, array-from 
only returns a slice when the rank of the result would be positive. wingo has 
pointed out that it is unusual to have a function name ending in a preposition. 

What do *you* think should be the names of these functions?



PS: The justification for these functions is given in the documentation, but in 
short: 1) other than the creation of the subarray descriptors, they don't cost 
any more than the rank-strict versions, 2) the only way to reproduce them in 
current Guile is with make-shared-array, which is very slow and cumbersome, 3) 
they recover a functionality that used to be part of Guile but was removed 
(‘enclosed arrays’). 

PPS: You can check out the functions at;a=shortlog;h=refs/heads/lloda-squash1.
 I rebase this branch on master periodically. The maintainers have reviewed it, 
but any extra reviews would of course be appreciated, especially of the doc.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]