SQL list of all the user defined functions in a database

You could use a CTE:

with functions(routine_name) as 
  (SELECT ROUTINE_NAME FROM information_schema.routines WHERE routine_type = 'function')
select 
  OBJECT_DEFINITION(OBJECT_ID(routine_name)) AS [Object Definition] 
from 
  functions

SELECT name, definition, type_desc 
  FROM sys.sql_modules m 
INNER JOIN sys.objects o 
        ON m.object_id=o.object_id
WHERE type_desc like '%function%'