PTQL

PTQL (Plain Text Query Language) is an exercise project that I'm using to help me in learning Common Lisp. PTQL implements an SQL like dialect in Lisp that is can be used to query plain text files (currently only CSV files are supported). This project is a work in progress.

Running the program

To run the program, use the SBCL implementation (There's a warning suppression macro which uses SBCL specific stuff, apart from that the program should run fine on any other implementation). I`ll try to make it portable some other time.

sudo pacman -Sy sbcl

Also, you must install ASDF. It may come installed with your implementation.

I recommend installing quicklisp. Their site contains precise instructions.

Clone the repo, then run Make on the repo main folder.

I also recommend installing rlwrap, because the default input sucks. This is optional, but the program is pretty lame without it.

cd <your-folder>/ptql
make
cd bin
rlwrap ptql

Querying text files

Suppose we had this file:

id,field,extra
1,joe,4
2,moe,4
3,doe,5

Import text files using import-table:

import-table #p"/home/user/file.csv" table

The file header column names will be used to refer to the columns.

Then, you may select from the table:

select * :from table

The results will be printed on the terminal.

Current, only where, order-by and limit are supported:

select (id field) :from table :where (> (length field) 5) :order-by (extra) :limit 10

You can use any valid Lisp expression on the where clause. On the order-by, use a list with the column names. You may order by descending as well:

select (field) :from table :order-by (name (extra desc))

Column names may also have white space. If it is so, refer to them by enclosing the name with |:

select (|person name|) :from some-other-table :where (= 90 |person weight|)

Other commands

There are no other commands (yet). Enter help to get a tip of the syntax. I'll be adding new stuff from time to time, although the current focus is to make the basic querying functionality as robust as possible.