I would like Phoenix to recognize casts to varchars that specify lengths, e.g. cast(x as varchar(10)). It is not an immediate goal to enforce the length, but at least to recongize the syntax.
(the reason I'm running into this is because I have sql generated by Optiq which uses these kinds of constructs)
I can easily hack the grammar to add this to the CAST grammar, but then I realize that the data type specification one can put in a cast is the same as what you can put in a column definition. Therefore, it would make more sense to introduce a separate rule to parse the data type and reuse that in the cast and column_def rules.
For arrays, the specification is currently not consistent:
- in column_def it is: ar=ARRAY? (lsq=LSQUARE (a=NUMBER)? RSQUARE)?
- in casts it is: ar=(ARRAY | (LSQUARE RSQUARE))? RPAREN
I assume this is not on purpose and can be aligned.
So in summary, what I'd like to do:
- introduce some object to hold the data type information, e.g. "DataTypeDef", which splits of the pure data type parts from ColumnDef, ColumnDef would then contain a DataTypeDef
- introduce a separate parser rule to match the data type specification, and which returns this new DataTypeDef object
- reuse this parser rule in the column_def and cast rules
- functionally, casts would stay the same for now
Alternatively, I can just add "(LPAREN l=NUMBER (COMMA s=NUMBER)? RPAREN)?" to the cast rule and be done with it.