Design: filter and find/search as functions and parameters on functions

[Affie]

Whats necessary to close this ticket:

• Work session on verbs
  • filter
  • find
  • search
  • list,
• Link the design artifact
• Ensure definitions exist in verbNoun dictionary

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Details

This issue is to discuss filters and find/search as functions and parameters on functions such as listVariables and getVariables

We can retrieve the objects or the labels with (We currently have filters on some get and list functions)

• get[Plural] returns a vector of object with optional filter
• list returns a vector of labels with optional filter

find[all] can be aliased to list if we wanted
findfirst can be used for a more efficient list()[1] (but list is not that expensive)

The main difference in findfirst and list will be the return type and error behaviour. list always returns a vector while with findfirst you would want the first element in the vector and nothing (julia way) if empty.

Then there is also search as an option, but I see that more for a bigger scope such as searching across all graphs in the DB.

What I think is still missing is an efficient and clear findfirst then get
We can just use get[Plural][1] to retrieve the first match with potentially bad performance.

We currently have getBlobEntryFirst that takes a filter on the label and returns the first match, similar to findfirst followed by a get or getBlobEntries[1] (with a filter)

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Maybe use verb retrieve for findfirst + get verb combination.

With findall returning labels of matches and findfirst returning the first match or nothing.
From julia docs:

findfirst(A) Return the index or key of the first true value in A. Return nothing if no such value is found.

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tasks:

• extra parameter / new verb / adjective
• list + filter vs findall - no find, aliased, or no filter in ls.
• get[Plural] + filter vs new verb
• findfirst + get with get[Plural] or new verb

xref #1085

[dehann]

Conditional +1 if good definition for list vs filter vs find?

retrieve = (find + get)

Sounds like both list and find do the same thing?

Knee jerk reaction:

find = list + filter

Does that mean we should change DFG.list_ to not have any filters, and rather change to findVariables(dfg, tags=[:Disco;])?

[dehann]

Also in bash list is not filter:

$ ls | grep -i "disco"

[Affie]

Sounds like both list and find do the same thing?

If we take inspiration from julia:

• list will be equivalent to findall
• we don't currently have findfirst (other than ls()[1]), but do have get...First, I think a verb may help

find = list + filter

That sound right to me.

Also in bash list is not filter

I think it's important to be able to combine list and get(plural) with filters for performance.

Also see edit on first comment

[Affie]

good definition for list vs filter vs find?

For filter I've just being using julia and see it as acting on a vector (ie. Vector{Symbol}).
list returns a vector of symbols from a graph for example.
findall = list + filter