SICP is Under Attack

Why not write a python(subset) interpreter in scheme?

The point is once you scan,tokenize and parse you get an AST. You already got a language that works on AST. I don't think python's AST is gonna differ a lot from scheme's.

The problem is that Python's AST looks different than Python. In Scheme there is no such intermediate step.

They don't write a scheme(subset) interpreter in scheme. They write a scheme interpreter in scheme.

If you make a degree a prerequisite to getting a specific job, or even a specific job at a specific (higher) pay scale, you always end up with people treating traditional four-year programs like trade schools. Especially if you also make people think of trade schools as where you go if you only barely passed high school, or if you failed high school and wound up with a GED. (And we could recurse and talk about how one-size-fits-all high schools aren't the only option, either, but we won't.)

Now you have four-year programs becoming the only option. This leads to a mix of philosophies, and by 'mix of philosophies' I mean 'raucous all-out war between two different groups punctuated by useless tracts calling for peace like this one.' The two different groups are the people who want to understand the theory at a respectable university level and the people who are on a fetch quest to get the paper to get the best ending (uh, job).

Neither group is wrong, but one group would be much better served by a non-stigmatized trade school system.

This fight invariably leads to the airing of two philosophies:

One, the student-as-customer philosophy, says that as long as tuition costs money the schools damned well better dance to the students' tune chop chop. They're more sympathetic than that once you realize how eager companies are to shitcan anyone who doesn't have enough letters after their name, which might actually be the real problem.

The other, the university-as-noble-institution philosophy, says that universities are places apart from the world where real research can be done and grants can be funded and, incidentally, there are these undergrad things running around that the exterminators refuse to extirpate so we might as well rope some researchers into making them the next generation of people educated enough to further our culture and, incidentally, keep our technical society from collapsing. In this model, the students don't get to influence pedagogy and coursework and so on because they, as per hypothesis, aren't educated enough to know what they want: If they were they could teach themselves and save everyone a lot of money.

Like I said, neither philosophy is wrong. It's just that one of them should be in a completely different set of institutions.

Python has things they call closures but they aren't what Scheme (or Lisp, or Perl, or Ruby, or Smalltalk, or JavaScript, or C#...) would call a closure. I think it's fair to say that Python is the odd language out here. The scoping rules are different unless you use the relatively recent "nonlocal" keyword.

http://stackoverflow.com/questions/141642/what-limitations-h...

And Guido has said that he intentionally crippled the lambda keyword.

http://www.artima.com/weblogs/viewpost.jsp?thread=147358

Anyway, why are you getting offended? Python is a great language.

Some people just think Scheme teaches certain aspects of programming better for various reasons. For instance, in Scheme, the program listing is a representation of the parse tree. Python will construct a similar tree, but this is not revealed to the programmer as much. So if you learn Scheme you can imagine how what Python is really doing (and writing parsers is much simpler because you have an intuitive sense of how they work).

And the ability to manipulate code as data is exclusive to s-expression based languages. This enables (for instance) truly hygienic macros. You don't get that in Python.

On the other hand, object-oriented programming in Scheme is pretty terrible. The part in SICP where they try to simulate it in Scheme is a travesty. Although it is somewhat illustrative of what's "really" going on, without the syntactic support it just looks ridiculous. So that's a win for Python.

Similarly, whipping up a complex data structure takes far fewer keystrokes, and is more transparent, in Pythonic syntax. Just as Scheme benefits from having built-in lists, Python wins even bigger for having lists and dictionaries everywhere. And overall Python is objectively more practical, with its vast array of libraries and ease of use.

I honestly don't know if you're trolling or are just being partisan. Not all languages are the same and there isn't any one "winner" language.