PL/pgSQL, PL/Perl, and PL/Python ship with WarehousePG and don't require a separate install. Enable them with CREATE EXTENSION in the target database.
The following procedural languages require a separate package install on each host:
Installing PL/Java
Enables writing functions in the Java programming language.Installing PL/R
Enables writing functions in the R programming language.
Installing PL/R also gives you access to the R Data Science Library. See R Data Science Library for details.