Handling a list of variable assignments to be used with `With`

Question

Is there a way to use With as follows?

variables := {a = 2, b = 3};
With[variables, a^b]

Desired output

Obviously the above code will actually just output

With[variables, a^b]

I know I can do something similar to this by defining a list of rules and using the operator form of ReplaceAll, I just like the way the With syntax looks and would prefer to use it if possible.

Hmm… I don't think it's a good idea, once the variables is executed somewhere, a and b will be polluted. — xzczd, Nov 08 '19 at 07:57
@Alexey do you think that one should be marked as a duplicate too? Is With/Block distinct enough to keep it separate from (24036)? — Mr.Wizard, Nov 08 '19 at 13:01
@Mr.Wizard In principle, yes, it should be market as a duplicate too. — Alexey Popkov, Nov 08 '19 at 15:00
@AlexeyPopkov Thanks! Yes this is a duplicate. Actually can I ask how you found that question? It was very difficult for me to successfully search for this question just because With is a common preposition. — Diffycue, Nov 08 '19 at 19:22
@Diffycue Heh, it was simple: I answered that question and simply remembered this when saw your question. But generally when searching it is helps to use appropriate tag(s): we are doing hard work on assigning appropriate tags for questions and it really helps a lot when you need to find somthing specific. In this case the tag scoping would help. — Alexey Popkov, Nov 08 '19 at 19:27
@AlexeyPopkov thanks so much! Btw I will be using your answer to that question since it best matches the kind of syntax I am after — Diffycue, Nov 08 '19 at 19:30

score 4 · Answer 1 · answered Nov 08 '19 at 08:16

4

A quick idiomatic approach is to do

Unevaluated[explicitExpression] /. OwnValues[variableWithSetDelayedDefinition]

You can find it in 76917 together with alternatives. See linked topics as well.

So here:

variables := {a = 2, b = 3};

With[variables, a^b] // Unevaluated // ReplaceAll @ OwnValues @ variables

8

answered Nov 08 '19 at 08:16

Kuba

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Linked topic or related ones do not seem to be close enough to be a duplicate but there is probably a duplicate somewhere. – Kuba Nov 08 '19 at 08:17
1

I reviewed the related questions and found a couple that I think work; let me know if you agree. Incidentally I reopened one of them, despite the fact that I was the one who closed it, because it really doesn't seem like a duplicate to me now. shrug – Mr.Wizard Nov 08 '19 at 09:05

Handling a list of variable assignments to be used with `With`

1 Answers1