Linq Query Support about fsharp.cosmosdb

[albert-du]

Currently I'm looking to support built in F# functions by replacing them with the BCL equivalents

Math operations are supported normally but not the F# versions

Math functions: Supports translation from .NET Abs, Acos, Asin, Atan, Ceiling, Cos, Exp, Floor, Log, Log10, Pow, Round, Sign, Sin, Sqrt, Tan, and Truncate to the equivalent built-in mathematical functions.
https://docs.microsoft.com/en-us/azure/cosmos-db/sql/sql-query-linq-to-sql

For example, trying to use the "abs" function in a query ce with Cosmos fails, but the equivalent "System.Math.Abs" method works.

This query builder is just to show extending the operations available by mapping F# functions to BCL methods.

[bartelink]

I know it's only an example, but can you clarify what sort of stuff you're intending to handle in your query support ?

I've not read or stretched it but I believe Microsoft.Azure.Cosmos has prerry complete LINQ support - are you intending to do some fixups in front of that, or replace the the whole engine?

If you're leaning towards the replacing the whole thing, it may also be worthwhile to peruse https://github.com/fsprojects/FSharp.AWS.DynamoDB (obviously it has a different query syntax, but there are lots of aspects of it which have been implemented very cleanly)

[aaronpowell]

I'll admit that I'm somewhat torn here - I like the idea of having a strongly-typed query engine, such as you get with LINQ, so that you can have more confidence in the queries that you write, but at the same time I ponder it relative to the analyzer part of this project (and which was one of the key motivations in building it). I want to explore a bit more how they play together, can we get better analysis of the query-to-generate by using LINQ, to maybe suggest where your projections are not valid for the database you're working with? I'm not sure, but it's something to explore.

[albert-du]

I believe Linq could be leveraged to provide greater insight with the analyzer. For instance, the Cosmos Linq provider allows for translation of strongly typed queries directly into sql which could be a basis for providing autocomplete suggestions or additional code linting.

[aaronpowell]

Yes, it does allow for strongly typed query creation because you're working off the in/out types, but I have to look at the analyzer and see if the type information is available - Last time I looked you were really only working with strings (as you're working on the tokens in the AST), but that might be outdated.