| There are a bunch of things to learn from Lisp: * list processing -> model data as lists and process those * list processing applied to Lisp -> model programs as lists and process those -> EVAL and COMPILE * EVAL, the interpreter as a Lisp program * write programs to process programs -> code generators, macros, ... * write programs in a more declarative way -> a code generator transforms the description into working code -> embedded domain specific language * interactive software development -> bottom up programming, prototyping, interactive error handling, evolving programs, ... and so on... The pioneering things of Lisp from the end 50s / early 60s: list processing, automatic memory management (garbage collection), symbol expressions, programming with recursive procedures, higher order procedures, interactive development with a Read Eval Print Loop, the EVAL interpreter for Lisp in Lisp, the compiler for Lisp in Lisp, native code generation and code loading, saving/starting program state (the "image"), macros for code transformations, embedded languages, ... That's was a lot of stuff, which has found its way into many languages and is now a part of what many people use. Example: Garbage Collection now is naturally a part of infrastructure, like .net or languages like Java and JavaScript. It had its roots in Lisp, because the need arose to process dynamic lists in complex programs, getting rid of the burden of manual memory management. Lisp got a mark & sweep garbage collector. That's why we say Lisp is not invented but discovered. Similar the first Lisp source interpreter. John McCarthy came up with the idea of EVAL, but thought it only to be a mathematical idea. His team picked up the idea and implemented it. The result was the first Lisp source interpreter. Alan Kay said about this: "Yes, that was the big revelation to me when I was in graduate school—when I finally understood that the half page of code on the bottom of page 13 of the Lisp 1.5 manual was Lisp in itself. These were “Maxwell’s Equations of Software!. EVAL is the E in REPL. Then Lisp had s-expressions (symbol expressions -> nested lists of "atoms"), which could be read (R) and printed. This is the "REP" part of the REPL. Looping it was easy, then. People then hooked up Lisp to early terminals. In 1963 an 17 year old kid ( https://de.wikipedia.org/wiki/L_Peter_Deutsch ) wrote a Lisp interpreter and attached it to a terminal: the interactive REPL. A really good, but large, book to teach the larger picture of Lisp programming is PAIP, Paradigms of Artificial Intelligence Programming, Case Studies in Common Lisp by Peter Norvig ( -> https://github.com/norvig/paip-lisp ). A beginner/mid-level book, for people with some programming experience, on the practical side is: PCL, Practical Common Lisp by Peter Seibel ( -> https://gigamonkeys.com/book/ ) Both are available online at no cost. |