4 REPL: the “top level”

SLIME uses a custom Read-Eval-Print Loop (REPL, also known as a “top level”, or listener). The REPL user-interface is written in Emacs Lisp, which gives more Emacs-integration than the traditional comint-based Lisp interaction:

• Conditions signalled in REPL expressions are debugged with SLDB.
• Return values are distinguished from printed output by separate Emacs faces (colours).
• Emacs manages the REPL prompt with markers. This ensures that Lisp output is inserted in the right place, and doesn't get mixed up with user input.

• REPL commands
• Input Navigation
• Shortcuts