Support complex predicates for IF function in PPL

[LantaoJin]

Description

The predicate of function if(predicate, arg1, arg2) in PPL should support complex expression.
The current implementation only supports TrueLiteral and FalseLiteral, just like the example given in doc. Query such as |eval test=if(pgs > 2, "yes", "no") will fail with "details": "Failed to parse query due to offending symbol [>] at:

This PR aims to support complex predicate expression, following cases will be supported:

• if(a > 2, arg1, arg2)
• if(a != 2, arg1, arg2)
• if(isnull(a), arg1, arg2)
• if(not a>2, arg1, arg2)
• if(not a in (0, 1), arg1, arg2)"
• if(not a in (0, 1) OR isnull(a), arg1, arg2)
• if(like(a, 'a%b%c_d'), arg1, arg2)
• and more

Issues Resolved

Resolves #2600 and #2653

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[penghuo]

Thx!

[dai-chen]

Thanks for the changes!

[LantaoJin]

None of current build issues caused by this PR.

[penghuo]

could u merge latest change from main and re-run test.

[LantaoJin]

Gently ping @penghuo @vamsi-amazon @YANG-DB

[penghuo]

Thx!

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/sql/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/sql/backport-2.x
# Create a new branch
git switch --create backport/backport-2756-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 593ffabbbdc6d6a9529ef3d6c233785e29fedb07
# Push it to GitHub
git push --set-upstream origin backport/backport-2756-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/sql/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-2756-to-2.x.