Added a section about meta-commands to developer documentation.

1 files changed, 31 insertions, 3 deletions

diff --git a/DEVELOP.rst b/DEVELOP.rst
index 42667fd1..2d163a4f 100644
--- a/DEVELOP.rst
+++ b/DEVELOP.rst
@@ -38,9 +38,14 @@ It is highly recommended to use virtualenv for development. If you don't know
 what a virtualenv is, this `guide <http://docs.python-guide.org/en/latest/dev/virtualenvs/#virtual-environments>`_
 will help you get started.
 
-Create a virtualenv (let's call it pgcli-dev). Once the virtualenv is activated
-`cd` into the local clone of pgcli folder and install pgcli using pip as
-follows:
+Create a virtualenv (let's call it pgcli-dev). Activate it:
+
+::
+
+    source ./pgcli-dev/bin/activate
+
+Once the virtualenv is activated, `cd` into the local clone of pgcli folder
+and install pgcli using pip as follows:
 
 ::
 
@@ -56,3 +61,26 @@ we've linked the pgcli installation with the working copy. So any changes made
 to the code is immediately available in the installed version of pgcli. This
 makes it easy to change something in the code, launch pgcli and check the
 effects of your change. 
+
+Adding PostgreSQL Special (Meta) Commands
+-----------------------------------------
+
+If you want to work on adding new meta-commands (such as `\dp`, `\ds`, `dy`),
+you'll be changing the code of `packages/pgspecial.py`. Search for the
+dictionary called `CASE_SENSITIVE_COMMANDS`. The special command us used as
+the dictionary key, and the value is a tuple.
+
+The first item in the tuple is either a string (sql statement) or a function.
+The second item in the tuple is a list of strings which is the documentation
+for that special command. The list will have two items, the first item is the
+command itself with possible options and the second item is the plain english
+description of that command.
+
+For example, `\l` is a meta-command that lists all the databases. The way you
+can see the SQL statement issued by PostgreSQL when this command is executed
+is to launch `psql -E` and entering `\l`.
+
+That will print the results and also print the sql statement that was executed
+to produce that result. In most cases it's a single sql statement, but sometimes
+it's a series of sql statements that feed the results to each other to get to
+the final result.
\ No newline at end of file