/^                  #Match at the beginning of the string
(                   #begin $1
[a-zA-Z_)[3,]       #A character class
.*                  #Any number of characters
?                   #Minimal match the .*
)                   #End $1
:                   #Match a colon
(                   #Begin $2
.*                  #Match until end of line
)/x                 #End $2 and the match