LPL

Many programming applications, e.g., symbolic and algebraic manipulation applications and artificial intelligence applications, require the use of list structures. Several list processing languages or languages that provide for list processing have been developed, e.g. LISP 1.5, LISP 2, SLIP, PL/1, ALGOL 68, etc. With the exception of ALGOL 68 and LISP 2, none of these languages provide the user with the capability to define the cell size and/or the configuration of the list cell at runtime (PL/1 attempts to do this with BASED structures but falls short because only one component in a BASED structure can have its dimension altered at runtime). ALGOL 68 has the disadvantage that it is not yet readily available for most users, and it suffers from list tracing complexities during garbage collection. LISP 2 was an attempt to allow variable cell configurations, but the project was aborted.