(SECD machine) The first abstract machine for reducing

lambda-calculus expressions, invented by P. J. Landin. The

machine has four registers holding pointers to linkedlists operated as push-down stacks which hold the

information required for the evaluation of an expression. The

registers point to (1) Stack which holds the arguments of

partially evaluated expressions and results of completely

evaluated ones, (2) Environment where the current expression

being evaluated is stored, (3) Control which holds the machine

instructions that manipulate the contents of the four

registers that represent the expression being evaluated, (4)

Dump on which the state of the machine is temporarily saved

during the evaluation of expressions. See also Lispkit.