New Issue: Range slicing syntax

17132, “vasslitvinov”, “Range slicing syntax”, “2021-02-09T08:17:53Z”

This issue asks whether we can improve the way range slicing is written.

In our range module review on 2/04 a few of us noted that the current way to slice a range unintuitive:


Here are our considerations:

  • The obvious alternative is to introduce a slicing method, ex. expr1.slice(expr2)
    especially that we already have localSlice methods.

  • Slicing is particularly useful on domains and arrays. Some prefer to write it with square brackets, as in expr1[expr2], although Chapel treats it the same as parens.
    Having to write A.slice[x..y] instead of A[x..y] can be seen as a step backwards.

  • We could potentially support both the paren form and a method.
    Although this goes against the principle that there should not be two ways of doing the same thing.

  • Whatever we do, it should be consistent between ranges, domains, and arrays.

  • If expr1 is range and expr2 is an integer,expr1(expr2) should be a valid “element access” (by analogy to indexing into an array), perhaps meaning orderToIndex #14884