Support Table Functions

[tshauck]

It'd be nice for exon to support table functions, e.g. SELECT * FROM read_fasta('./path/to/file.fasta.gz'). It should support taking 0 or more arguments.

At least two things are needed to support table functions:

1. Support in query planner to recognize the case when a table function is used. This likely builds off: https://github.com/apache/arrow-datafusion/tree/master/datafusion/sql
2. Based on the recognition of table function, convert it into the appropriate scan execution.

Start with a read_fasta and move onto other functions.

[tshauck]

Datafusion plans to add support for this, so wait for its release: apache/datafusion#7926

[tshauck]

Scan Functions

• BAM - A BAM file.
• BCF - A BCF file.
• BED - A BED file.
• FASTA - A FASTA file.
• FASTQ - A FASTQ file.
• FCS - An FCS file.
• GENBANK - A GenBank file.
• GFF - A GFF file.
• GTF - A GTF file.
• HMMDOMTAB - A HMMER DOMTAB file.
• MZML - An mzML file.
• SAM - A SAM file.
• VCF - A VCF file.

Indexed

• INDEXED_BAM - A BAM file with an associated index file.
• INDEXED_VCF - A VCF file with an associated index file.

Misc

• Docs