Compiling will not change READ into PARSE. READ is still there. > Most CL implementations compile before calling eval Many or a lot, but I'm not sure actually

Compiling will not change READ into PARSE. READ is still there. > Most CL implementations compile before calling eval Many or a lot, but I'm not sure actually most. There are quite a lot which use an Interpreter in the REPL, but where one can compile on demand. SBCL by default compiles. LispWorks for example does not. > After it's reader is done with it, the code is represented with CL data structures. Right, but the data structures carry no syntactic information. If you write (1 2 +) the reader accepts it and does not know that this is invalid syntax. > AST and IR are all CL data structures. True, but not necessarily like s-expressions... See for example data structures the SBCL compiler uses: https://github.com/sbcl/sbcl/blob/master/src/compiler/node.lisp https://github.com/sbcl/sbcl/blob/master/src/compiler/node.l... > Saving the image and exiting the runtime is like compiling in normal languages. Working with images is optional - the Common Lisp standard says nothing about images at all.