DSL's or Domain Specific Languages

I saw this at Adobe MAX last year and I finally got a chance to try it out. DSL or Domain Specifically Languages are languages that only reside in a domain, in our case the web app we are developing. A good example of where DSLs are used is in gMail in the search box. If you haven't noticed it yet they are really handy, but they only work in gMail. Another good one is MS Outlook, they support crazy operators. Here is what one would look like:



I grabbed this one from gMail. The convention seems to use a keyword followed by a ":". In the case above it's "from:". I have only found DSLs helpfully for search boxes. If you are going to use DSLs you need to have legend so your users know what keys are available. You need to support it everywhere or tell the user where it is supported. If you are going to use them you should do whatever it takes in the keys and language to make it easier for the user. DSLs should be quick to use. Some advanced DSLs might look like this "from:(name:*joe)" or something like that or if operators are involved.

Once the user enters the DSLs you need to parse the string and do something with it. I create a query criteria snippet for sql or orm queries to allow the user to search across other things in the search box.

DSLs aren't really user friendly that's why I would recommend "search areas". Search areas are much easier to read, but less flexible. I posted on it early tonight here.