> The ability to evaluate code interactively without recompilation
SBCL and other implementations compile code to machine code then execute it. That is to say, when a form is submitted to the REPL, the form is not interpreted, but first compiled then executed. The reason execution finishes quickly is because compilation finishes quickly.
There are some implementations, like CCL, with a special interpreter mode exclusively for REPL-usage.[1] However, at least SBCL and ECL will compile code, not interpret.
SBCL and other implementations compile code to machine code then execute it. That is to say, when a form is submitted to the REPL, the form is not interpreted, but first compiled then executed. The reason execution finishes quickly is because compilation finishes quickly.
There are some implementations, like CCL, with a special interpreter mode exclusively for REPL-usage.[1] However, at least SBCL and ECL will compile code, not interpret.
[1] https://github.com/Clozure/ccl/blob/v1.13/level-1/l1-readloo...