We got a cool feature request to support gzip decode which has me excited for additional binary string features like, • base64 encode/decode • gzip/lz4/zstd/snappy Are there other features in this domain that people are excited about or have wanted? 🧵

i saw your comments on the issue specifically

# decode as "gzip" or return NULL on failure

col("my_bytes").try_decode("gzip")

in another issue/PR you mentioned the need for

try_cast

An expression that I really want to add is a

try

expression, instead of individual

try_

methods.

This could be pretty cool to flesh out alongside the existing SQL control-flow operations: coalesce, case-when, nullif

I also wonder if our casts should be more appropriately defined under the hood... e.g. • str to int cast should call out to a

stoi

expression or similar • int to string cast should call a

to_string

expression • string to date should call a

strptime

expression • date to string can call a

strftime

expression, with a default setting (e.g.

YYYY-MM-DDTHH-MM-SS

) etc etc This would make our casting docs easier (we can call out exactly which expression we call out to under the hood for various cast operations) and also allow people to be more explicit when moving between different datatypes...

Named cast methods are quite nice and are common in some SQL dialects too. The named cast methods can also be nice when you want a cast that has different semantics and optional parameters which differ than an SQL CAST which is highly prescriptive in the standard. The only thing to solve would be argument handling, but this plays well with the receiver comment I just made 🙂

class Expr:
   def to_str(self):
       # a cast with no type args

   def to_decimal(self, precision, scale):
        # cast with args

# daft.functions

def to_str(expr): ...

def to_decimal(expr, precision, scale): ...

All great ideas!

I love language design 😄

Just left a review, Functionally it looks fine, but I did leave some comments about performance concerns.

I'll update because I'd like to improve my contributions here. I followed precedent from the previous functions which, applying your feedback, could also be improved.