Implement hasKey resource

[czerwinskilukasz1]

I wanted to write a piece of code that in Javascript looks like this:

if (!(a in leftMostPosition)) {
   leftMostPosition[a] = i;
}

Alas, I couldn't find any way to express it, because I didn't find a resource for it.
Please note that comparing leftMostPosition[a] with any value would not work as there is no undefined value in AskScript, only null, which could be a legitimate value of leftMostPosition[a].

[czerwinskilukasz1]

@mhagmajer

[mhagmajer]

@czerwinskilukasz1 would the following make sense? We would need a hasKey resource for that

if (not(leftMostPosition:hasKey('a'))) {
   leftMostPosition[a] = i;
}

[czerwinskilukasz1]

hasKey sounds good to me. Renaming the task.

[czerwinskilukasz1]

Task:

Implement a hasKey resource. All list-related resources live in src/askvm/resources/list directory. Check other resources from the directory to grasp how they work.

[cpelican]

Hi, I would be interested in submitting a pr for this issue, is it fine with you? Thanks!

[czerwinskilukasz1]

Hello @cpelican , it sounds awesome!

[czerwinskilukasz1]

@cpelican, the issue is yours.
In addition to creating code to hasKey, please write also a test file (or a couple) in AskScript language in src/askscript/__tests__/07-arrays.
Let me know if you have any questions. We would love to hear feedback, e.g. if we are missing some documentation or guides for new contributors.

[cpelican]

Hi @czerwinskilukasz1, @mhagmajer, I would have 2 questions:

• I just added tests in src/askscript/__tests__/07-arrays, but before that i had noticed there were tests in askvm/resources/list/, so i had added some tests also there. Would you prefer if all tests were in the same directory or do these both places have different purposes?
• The place where the code belongs indicates me this resource should apply to a list or array. But the use case of this issue made me think that this could be used for objects as well. Would you like it to work only on arrays or also on objects?
  Thanks!

[czerwinskilukasz1]

Hi @cpelican ,

Hi @czerwinskilukasz1, @mhagmajer, I would have 2 questions:

• I just added tests in src/askscript/__tests__/07-arrays, but before that i had noticed there were tests in askvm/resources/list/, so i had added some tests also there. Would you prefer if all tests were in the same directory or do these both places have different purposes?

So, tests in src/askscript/__tests__ are testing AskScript language, while tests in src/askvm/**/__tests__ test more low-level AskVM resources and the code is written in AskCode. Think of AskCode as an "assembler" for AskVM, while AskScript is a user-facing language (like C# or Javascript). Here is a diagram showing how different they look:

Also, tests in AskCode we write are usually much much shorter, limited to just one expression, while tests in AskScript tend to be a complete program.

• The place where the code belongs indicates me this resource should apply to a list or array.

This is a good remark. I would save the resource in src/askvm/resources/list for now, but be prepared @mhagmajer might propose a better place after you create your PR.

But the use case of this issue made me think that this could be used for objects as well. Would you like it to work only on arrays or also on objects?

Great question. Yeah, I should have be more clear. I meant both arrays and objects.

[cpelican]

@czerwinskilukasz1 ok, thank you for your answer!