If you are curious of namespaces existing in your q process, use key function with ` as parameter.
Let’s check which namespaces exist when the process is started:
q) key`
`q`Q`h`o
Moreover, you can use key to list the content of namespace:
q) key `.foo
`init`func`c
Note that in this way we get everything what resides in the namespace but we cannot distinguish between tables, functions and variables. If you need to list only one of these, use \a, \f or \v, e.g.,
q) tab:([] a:1 2 3; b:`a`b`c)
q)\a
,`tab
me, q and kdb+ 
good info thank you!
I’m hitting the constants error for q session.
Is it possible to list all the variables and their values, possibly even by namespace where the variable type is not a table?