Common Lisp Sucks

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A collection of negative quotes on Common Lisp. This is originally collected in a post to comp.lang.lisp newsgroup by “WJ” 〔w_a_x_…〕 @ Source

Guy L Steele

Guy L. Steele, Jr.'s foreword in Scheme and the Art of Programming.

I think we may usefully compare the approximate number of pages in the defining standard or draft standard for several programming languages:

  Common Lisp   1000 or more
  COBOL          810
  ATLAS          790
  Fortran 77     430
  PL/I           420
  BASIC          360
  ADA            340
  Fortran 8x     300
  C              220
  Pascal         120
  DIBOL           90
  Scheme          50
  • Scheme and the Art of Programming By George Springer, Daniel P Friedman. @ amazon

Rodney A Brooks, Richard P Gabriel

Every decision of the committee can be locally rationalized as the right thing. We believe that the sum of these decisions, however, has produced something greater than its parts; an unwieldy, overweight beast, with significant costs (especially on other than micro-codable personal Lisp engines) in compiler size and speed, in runtime performance, in programmer overhead needed to produce efficient programs, and in intellectual overload for a programmer wishing to be a proficient COMMON LISP programmer.

Richard P Gabriel home page: Source

Richard Gabriel

Common Lisp is a significantly ugly language. If Guy and I had been locked in a room, you can bet it wouldn't have turned out like that.


Paul Graham

Paul Graham (computer programmer)

Historically, Lisp has been good at letting hackers have their way. The political correctness of Common Lisp is an aberration. Early Lisps let you get your hands on everything.

A hacker's language needs powerful libraries and something to hack. Common Lisp has neither. A hacker's language is terse and hackable. Common Lisp is not.

The good news is, it's not Lisp that sucks, but Common Lisp.

Do you really think people in 1000 years want to be constrained by hacks that got put into the foundations of Common Lisp because a lot of code at Symbolics depended on it in 1988?

Daniel Weinreb

Daniel Weinreb.

Having separate “value cells” and “function cells” (to use the “street language” way of saying it) was one of the most unfortuanate issues. We did not want to break pre-existing programs that had a global variable named “foo” and a global function named “foo” that were distinct. We at Symbolics were forced to insist on this, in the face of everyone's knowing that it was not what we would have done absent compatibility constraints. It's hard for me to remember all the specific things like this, but if we had had fewer compatibility issues, I think it would have come out looking more like Scheme in general.

Lisp2 means that all kinds of language primitives have to exist in two versions, or be parameterizable as to whether they are talking about the value cell or function cell. It makes the language bigger, and that's bad in and of itself.

Gilles Kahn

Gilles Kahn (1946〜2006):

To this day I have not forgotten that Common Lisp killed Lisp, and forced us to abandon a perfectly good system, LeLisp.

Jeffrey M. Jacobs

Jeffrey M. Jacobs:

I think CL is the WORST thing that could possibly happen to LISP. In fact, I consider it a language different from “true” LISP.


Common LISP is the PL/I of Lisps. Too big and too incomprehensible, with no examination of the real world of software engineering.

… The CL effort resembles a bunch of spoiled children, each insisting “include my feature or I'll pull out, and then we'll all go down the tubes”. Everybody had vested interests, both financial and emotional.

CL is a nightmare; it has effectively killed LISP development in this country. It is not commercially viable and has virtually no future outside of the traditional academic/defense/research arena.


One of the key issues that I consider distinguishes “Real LISP” from Common LISP is indeed the strong committment to the equivalence of data (meaning list structures) and code. I consider this idea one of the foundations of “Real LISP”, and Common LISP intent is vague at best. InterLISP, for example, still makes a declaration of this philosophy in the manual, and it is still one of the keystones in the teaching of LISP (although whether it should be when teaching Common LISP is open to question).

Chez Bernard Lang

Chez Bernard Lang:

Common Lisp did kill Lisp. Period. (just languages take a long time dying …) It is to Lisp what C++ is to C. A monstrosity that totally ignores the basics of language design, simplicity and orthogonality to begin with.

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