feat(hogql): better handling of known types for function calls

[thmsobrmlr]

Problem

HogQL doesn't know about the return types of functions, preventing us from having a fully-typed experience.

This can be seen in the generated ClickHouse SQL e.g. 2 = 1 + 1 currently becomes:

SELECT ifNull(equals(2, plus(1, 1)), 0)

After this PR it becomes the expected:

SELECT equals(2, plus(1, 1))

Further down the line we can add better auto-complete etc.

Todos

• Investigate errors
• would be great to have signatures for comparision functions e.g. greaterOrEquals, as they are used much
• would be great to have signatures for transform
• there seems to be some kind of issue with the timezone param - see error message

Changes

This PR adds signatures for most supported HogQL functions, as well as handling for the return types in HogQL.

How did you test this code?

CI run

select 2 = 1 + 1
select (1,2) = (1,2)
select [1,2] = [1,2]
select now() = now()

[posthog-bot]

This PR hasn't seen activity in a week! Should it be merged, closed, or further worked on? If you want to keep it open, post a comment or remove the stale label – otherwise this will be closed in another week. If you want to permanentely keep it open, use the waiting label.

[posthog-bot]

This PR hasn't seen activity in a week! Should it be merged, closed, or further worked on? If you want to keep it open, post a comment or remove the stale label – otherwise this will be closed in another week. If you want to permanentely keep it open, use the waiting label.