Based on (metacircular Scheme) evaluator in Structure and Interpretation of Computer Programs (SICP)
what it is
an interpreter for a lexically-scoped, minimalist-designed, dialect of lisp
it is initially nowhere close to R5RS- or R6RS-complient
the following operands (in alphabetical order) are implemented
- define (the minimalist one for now)
at the momemnt you need to implement cons, car and cdr yourself using lambda. :)
how it works
It basically works by doing two things ->
- to evaluate a combination (a compound expression other than a special form), it evaluates the subexpressions and then applies the value of the operator subexpression to the values of the operand subexpressions.
- to apply a compound procedure to a set of arguments, it evaluates the body of the procedure in a new environment. To construct this environment, it extends the environment part of the procedure object by a frame in which the formal parameters of the procedure are bound to the arguments to which the procedure is applied.
in-browser example (evaluates each keypress)