The lambda character λ, always struck a awe in me, as with other mathematical symbols. In my mind, i imagine that those obscure math symbolism are etched in stone by god. A salient example is the book cover Concrete Mathematics by Ronald Graham et al. amazon
Here we see the summation sign ∑ etched in stone. The summation sign happens to be my favorite math symbol. (chosen as my website signet: )
These symbols are not to be trifled with. If anyone puffs in as much half a snicker, i wish god strikes a thunder upon their impudence.
The Greek lambda symbol is used in a branch of logic called lambda calculus. The theories of lambda calculus is what functional languages are based on, thus many functional language's logo feature the lambda. Here is a collection of functional language's logos involving the lambda.
MIT Scheme is a grand daddy of Scheme lisp. Its logo features a recursive shield with lambda. http://www.swiss.ai.mit.edu/projects/scheme/
This logo has a modern look. It is a simple lambda inside a O figuration. Though, i was told this “O” is supposed to be a pair of parenthesis.
PLT Scheme's logo, notable is the red/white/blue coloring scheme. PLT Scheme changed its name to Racket in 2010-06. Home page: racket-lang.org.
MzScheme is part of PLT Scheme. The logo features a lambda besides a Chinese character 文 (wen2). The character means written language.
It is made of 5 math symbols revolving around a big lambda. The symbols are: right arrow →, inverted A ∀, double right-pointing angle bracket ≫, double colon ::, double right arrow ⇒, and lambda λ. The right arrow → signifies transformation. The inverted A ∀ signifies “for all”. The double angle ≫ signifies free from disorder. The double colon :: signifies exactitude. The double right arrow ⇒ signifies generality. Finally, the lambda λ signifies functionality.
This logo's concept is based on ASCII art by Darrin Thompson, and interpreted by Jeff Wheeler. It is a result of public logo contest. For detail, and many quality logo entries, see http://www.haskell.org/haskellwiki/Haskell_logos/New_logo_ideas.
I love these lambda-featuring logos. However, i have a complaint. As most of you know, lisp languages are not purely functional languages. Subroutines in lisps easily have side-effects, and sometimes non-functional programing methodologies such as OOP are actually encouraged in lisp. As most of you know, the lambda symbol chosen by functional languages is to signify no side-effects. In this respect, i find the lisp languages not totally deserving the use of lambda in their logo. As i have expressed before, mathematical symbols are not to be trifled with, and the Schemers have tainted my mathematics, strictly speaking.
Although i have this minor objection with lispers using the lambda symbol, but overall i think the lispers and i share a more important common goal. That is, to kill all imperative programing ignoramuses of the world. Once the unix and C and Perl and otherwise idiots are all dead, then i'll formally raise my objection about Lisper's unfit borrowing of the lambda symbol.
Addendum, 2003-05, …, 2010-09-25
The PFP library for Haskell features a lambda disguised as a histogram. One of the most well-designed among lambda logos. (“A Probabilistic Functional Programming Library for Haskell” by Martin Erwig and Steve Kollmansberger, 2005. http://web.engr.oregonstate.edu/~erwig/pfp/).
Someone has written a C++ library for functional programing, called FC++. (by Brian McNamara and Yannis Smaragdakis, 2003) Website: http://cgi.di.uoa.gr/~smaragd/fc++/
Chicken Scheme features a logo that is a lambda inside a hen silhouette. (by Felix L Winkelmann, at call-cc.org).
This is getting silly and disrespectful.
I prefer the original yellow hen logo. This new modern-looking logo lost its soul. You can't easily tell what bird it is, and the funky lambda takes some tech geeking to recognize. The original logo of the fat hen signifies birth, with lambda right in its tummy, and fits well with the project's comical name Chicken Scheme. This is a example where logo with elegant artwork is not necessarily the best.
For some history of CHICKEN scheme's logo, see
Here's some collection of lisp logos that does not involve lambda.
CLforJava is a Common Lisp implementation on Java Virtual Machine. Home page: clforjava.org.
Clozure Common Lisp is formally OpenMCL, which is derived from Macintosh Common Lisp (MCL). Home page is at: