LISP, Little Insignificant Stupid Parentheses.
LISP has been jokingly maligned for much of my life. Others write praises and dub it Alien Technology or a Secret Weapon.
LISP is a customizable compiler/interpreter where the source code modifies the compiler at run time.
Generally, the model a compiler/interpreter in these four phases:
- Lexical analysis - scan for token
- Syntax analysis - build Abstract Syntax Tree, the AST.
- Optimization - analyze and refine the AST
- Machine Coding - Excutute the AST or encode the AST for later execution.
In LISP the syntax is simple paren encoded lists called s-expressions. LISP source code is a paren encoded AST. The lexical READER strips away the parens under control of LISP functions and macros and a LISP data form, an s-expression, is produced. Because this data form is an AST of the program the AST can be optimized before it is converted to executable code. The data form is evaluated under LISP rules which are in many places customized by LISP function and macros from the LISP program source. The LISP PRINTER adds the parens format to output result form where necessary under the control of LISP functions and macros.