2.7 KiB
cons-lists
A Javascript1 implementation of Lisp-like cons(), using vectors
1Technically, Coffeescript, but it's just Javascript.
Purpose
I kinda got tired of my broken list implementations that I was working with in each and every variant of Lisp I wrote while working my way through List In Small Pieces, so I decided to break it out into its own managed repo.
API
A cons is a singly-link list consisting of pairs, two-position objects. In a true cons list, the leftmost cell (the "car") contains a data object of interest, and the rightmost cell (the "cdr") contains a pointer to the next pair. Cons lists traditionally end with a cdr object pointing to an empty list. The following functions are provided to create, identify, traverse, and modify cons lists.
nil
: An empty list, used as a static sentinelcons()
: Construct an empty listcons(obj)
: Create a new list of one objectcons(obj, lst)
: Append an object to the head of an existing listcar(lst)
: Return the contents of the current cell, or nil.cdr(lst)
: Return a reference to the next item in the list, or nil.nilp(lst)
: (Boolean) is list an empty list?pairp(obj)
: (Boolean) is this a object a pair?listp(obj)
: (Boolean) is this object a list?list(a, b, ...)
: Construct a list out of the argumentsvectorToList(v)
: Return a cons list given a vector. Recursive: if a vector is encountered inside v, it will be converted to a cons list.listToVector(l)
: Return a vector given a cons list. Recursive: if car(l) is itself a cons list, the returned vector will contain an internal vector at that position.setcar(obj, l)
: Replace the contents of car(l) with objsetcdr(obj, l)
: Replace the contents of cdr(l) with objcadr(lst), cddr(lst), cdar(lst), caar(lst), caddr(lst), cdddr(lst), cadar(lst), cddar(lst), caadr(lst), cdadr(lst)
: Common lisp functions that extend standard list addressing.metacadr(string)
: For more complex addressing, metacadr() can be provided with a string that describes the address desired, and returns the qualifying function. For example, this library does not provide caddddr(), but it can easily be generated: metacadr("caddddr") will return a function to get the data content of the fifth cell.
Requirements
coffee-script
to compile the library.chai
,mocha
,coffeelint
,mocha-jenkins-reporter
for development.
See package.json
for details.
Installation
npm install https://github.com/elfsternberg/cons-lists.git
Credits
Elf M. Sternberg elf.sternberg@gmail.com
LICENSE AND COPYRIGHT NOTICE: NO WARRANTY GRANTED OR IMPLIED
Copyright (c) 2015 Elf M. Sternberg
Licensed under the MIT License. See the LICENSE
file for full text.