cons

Function: cons

file: job.t
package: muf
status: alpha

The cons function takes two values and constructs a List cell containing them as it's car and cdr:

Stack:
"a" "d" cons -> cell
Stack: 
cell car   cell cdr
Stack: "a" "d"

The name is short for "construct", since it constructs a cons cell, the basic unit of storage in classical lisp systems.

List cells are often called "cons cells", since they are constructed by cons, or simply "conses", and the process of constructing them is often called "consing".

It is possible to implement arbitrary programs using only cons to modify memory; This train of thought leads to the pure-functional programming community. If this intrigues you, you might grab a Haskell implementation from cs.yale.edu or join the mailing list via haskell-request@cs.yale.edu.

You may sometimes wish to allocate a cons cell on the stack instead of on the heap: The function ephemeralCons will do this. For brevity, it is also available under the synonym econs. The usual cautions pertaining to ephemerals apply: See section ]makeEphemeralVector.

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