PPLISP

this is a set of 45 macros that allow for lisp-like preprocessor meta programming.

USAGE

to use PPLISP in your project just include PPLISP.h

#include "PPLISP.h"

including PPLISP.h a second time will undefine all of the PPLISP macros.

to evaluate a PPLISP:TM: expression use the following

EXP( EVAL ( /*expr*/ ) )

the EXP macro applies 3^10 or so scans of the preprocessor and the EVAL macro does all of the hard work of figuring out what your expression means.

expressions

a pplisp expression has the following format (MACRO, EXPR1, EXPR2, ..., EXPRN) the result of evaluating EXPR1, ..., EXPRN are passed to MACRO as ARG1, ... ARGN

primitives

the following macros are defined for use as PPLISP primitives

QUOTE ($) evaluates to the list of its unevaluated arguments

the $ macro appends QUOTE to the front of its argument list EX: $(a, b, c) => (QUOTE, a, b, c)
CONCAT concatenates arrays passed to ARG1 and ARG2 and returns the result
IF if ARG1 evaluates to (T) then return the result of evaluating ARG2

if ARG2 evaluates to (F) then return the result of evaluting ARG3
FST returns the first element of the list passed to ARG1
RST returns all but the first of the elements passed to ARG2
IS_NIL if the list passed to ARG1 is empty evaluates to (T) otherwise it evaluates to (F)

defining additional PPLISP primitives

to define additional primitives simply make a macro like so

#define M_MACRONAME MACRONAME
#define MACRONAME(ARG1, ARG2, ..., ARGN)EVAL( /*expr*/ )

recursive primitives are totally allowed, feel free to experiment!

examples

here is an example of a NOT macro

#define M_NOT NOT

/* the trailing \ tells the preprocessor to delete the newline allowing for multiline macro definitions*/
#define NOT(a) EVAL\
((IF,$ a,\
	$(F),\
	$(T)))

/*without the $() EVAL will attempt to evaluate T or F which doesn't make any sense*/

EXP(
EVAL(
    (NOT, $(T)) /*evaluates to (F)*/
)
EVAL(
    (NOT, $(F)) /*evaluates to (T)*/)
)
)

cospplredman / PPLISP