Re: Discuss changing the behaviour of append()
- Posted by DerekParnell (admin) Jun 10, 2014
- 5045 views
I think the basic problem is that S[i] is not (fully) a sequence.
Every slice is a sequence,
S[i] has a length so it is a sequence,
Yet it can type as an atom.
It seems what you need here is an operator which 'converts' an atom to a sequence.
S[i] & {} -- would work as well as S[i..i] -- but they are fixes
Unfortunately, this is NOT the issue. I'll restate the problem using different words.
Given an object X, I want to create a sequence by adding another object Y, such that the last item in the newly created sequence is Y, and all the other items in X are unaltered.
Examples ...
X = 4 Y = {8,9} --Result is {4, {8,9}} X = {4} Y = {8,9} --Result is {4, {8,9}} X = {4,5} Y = {8,9} --Result is {4, 5, {8,9}} X = {} Y = {8,9} --Result is {{8,9}}
In all but the first case, the append() function will suffice. But with the first case I need to convert X to a sequence first. That is what I'm hoping to avoid doing; the 'manually' conversion. Instead I'd like Euphoria to do it automatically.
The only suggestion so far that works in each of the case above is the 'concatenate a sequence' trick, but that has a performance hit of creating a temporary sequence and then disposing of it after the operation has completed. Something I'd also like to avoid.
object X, Y X = 4 Y = {8,9} X &= {Y} --Result is {4, {8,9}} X = {4} Y = {8,9} X &= {Y} --Result is {4, {8,9}} X = {4,5} Y = {8,9} X &= {Y} --Result is {4, 5, {8,9}} X = {} Y = {8,9} X &= {Y} --Result is {{8,9}}
So, if the change is made to Euphoria's append()/prepend() functions to do this, programs that now currently fail in this situation will no longer fail. Is that okay?
