SimpleFUN) Typechecker, Due Tuesday, February 14
PolyFUN) Typechecker, Due Wednesday, February 22
SimpleFUN) Interpreter with Small-Step Operational Semantics, Due Wednesday, March 8
mini-prolog) with Small-Step Operational Semantics, Due Friday, March 24
In general, if you want to know what sort of methods are available, along with their signatures, Googling for
scala class-of-interest will give you a lot of information.
For example, if you want to know how to use Scala's
Seq class (representing
Sequences), then Googling for
scala Seq should turn up the
scaladoc (Scala's equivalent of
This will give you the methods and method signatures on
Seq, along with its position in the inheritance hierarchy.
In general, unless we explicitly say otherwise, you may not use mutable state in your assignments.
This includes both mutable variables (i.e., those introduced with
var), along with mutable data structures (e.g., arrays, most everything in
When in doubt, ask us if something is ok to use.
Using mutable data in an unauthorized way will hurt your grade significantly.
The reason for this restriction is to intentionally force the usage of functional programming, which strongly discourages mutable state.
Without this restriction, you are basically writing Java in Scala, and not really learning Scala or functional programming.
It is not necessary to look at any of these books to understand the course material. These links are here only for those who are interested in learning more about Prolog. I own all the books listed, and I would be happy to let you take a look at them.
Prolog, and logic programming overall, behaves very differently from other programming languages.
It is expected to be challenging to pick it up, because in many respects you'll be learning programming all over again.
trace clause is your friend here, which will give you a whole lot of debugging information.
For example, if you do
trace, foo(X)., this will show all the steps taken while calling
foo with the parameter
X, which is extremely valuable.
This includes information regarding values passed back and forth, which is more than what one usually gets with a stack trace.
To keep things simple, I advise against the use of metaprogramming and extra-logical features, including, but not limited to:
You may use the above features without penalty, but there is no assignment which requires you to do so. The reason why I advise against these features is that they do not mix well with the rest of Prolog, and are really hacks which have been done to the language in order to make it more flexible. Proper use of these can lead to very clean code, but they are semantically complicated and they are all special cases in the language. To this date, I have not seen a student use any of these features correctly, and broken code was the result.
Additionally, as with the Scala assignments, you may not use mutable state in your assignments.
This includes features which dynamically modify the clause database (e.g.,
retract), as well as global mutable variables in SWI-PL (accessed through
There are no cases in which the usage of these is permitted, so using them will hurt your grade significantly.
As with Scala, we want you to learn Prolog, not to learn how to force C or Java into Prolog.
Additionally, these features are extremely error-prone, even moreso than the extra-logical features discussed previously.
Case in point, I have found bugs in SWI-PL libraries involving improper use of
nb_setval, and I have seen students use these in ways which were subtly incorrect.