Here are some choice-quotes that are one of {insightful, controversial, arguable}:
Starting with my favorite quote ;):
"The ability to operate on the program as data is basic to the provision of
many desirable utilities, e.g. the Boyer-Moore theorem prover, and the program
transformation work that was based on Hope, not to mention a compiler.
It seems unfortunate that recent functional languages are heteroousian in the
sense that they are defined in the usual computer scientist's way of specifying
a syntax, and not specifying a representation of a program as a
data-structure. This is a manifestation of the besetting vice of computer
scientists - they will insist in locking up goodies in a black box..."
On Lisp:
"There is a danger that this perspective will adversely affect the design of a
language from the user's point of view. The most extreme case is that of LISP,
which may be seen as a very flawed implementation of the Lambda Calculus,
which preserves the notation rather closely."
On Haskell syntax:
"However, if the use of upper case is not permitted for
ordinary variables a conflict arises between the language conventions and the
conventions of mathematics,...."
"Haskell is also in conflict with established programming conventions in that
it it uses double colon to denote membership of a type (e.g. x::Int) rather
than the single colon that those millions of existing programmers will be
familiar with,.."
On Haskell arrays:
"The Haskell array operation is a related construct, from which a instances of
the application of the POP-11 newarray could be implemented - it does however
suffer from one practical draw-back, namely it takes an association list as
argument, which makes it inefficient as a means of memoising a function,
unless a very smart compiler is used."
On purity:
"I want a language that is not purely functional because functional
languages do not reflect the basic structure of computers. If you want to
write a matrix inversion algorithm it will be hard to do it efficiently
without assignment."
Matt