The Logo Programming Language, a dialect of Lisp, was designed as a tool for learning. Although there are some versions of Logo that compile, it is generally implemented as an interpreted language. The interactivity of this approach provides the user with immediate feedback on individual instructions, thus aiding in the debugging and learning process.
Error messages are descriptive.
There's no error message. Modularity and Extensibility Logo programs are usually collections of small procedures. Generally, procedures are defined by writing them in a text editor. The special word to is followed by the name of the procedure. Subsequent lines form the procedure definition.