The first few questions for
ChatGPT
I finally opened an account to beta-test ChatGPT. I must say, I am
quite impressed. I asked it a few questions that I could have asked
during an interview. To my surprise, the answer given was, while wrong,
believable enough to kind of sneak the answer as right up to some
imprecision. Like if you squint enough, it could pass, but if you pay
attention it is clearly false.
So yes, mainly ChatGPT in this interaction was quite good at being
convincing. This is the same kind of impression you have from looking at
AI generated images. At first sight everything seems fine, but if you
start looking to the details, many things are off.
So here is the full interaction, I'll let the attentive reader find
the technical problems:
Can
you write a clojure function that will reverse any string provided to
it.
ChatGPT: Sure, here's a possible implementation of a
function that reverses a string in Clojure:
(defn reverse-string [s]
(apply str (reverse (seq s))))
This function takes a strings as input, converts it to a sequence of
characters using the seq function, reverses this sequence
using the reverse function, and then converts the resulting sequence
back to a string using the apply and str
functions.
Here's an example of how you can use this function:
user=> (reverse-string "hello world")
"dirow olleh"
Note that this function only works for strings that contain
characters in the Unicode Basic Multilingual Plane (BMP), since the
seq function only works on strings that contain characters
in this range. If you need to reverse strings that contain characters
outside of the BMP, you can use the string-seq function
instead of seq to convert the string to a sequence of
characters.
How
would this function react if instead of string you provide an
integer?
ChatGPT: If you provide an integer as input to the
reverse-string function instead of a string, the function
will fail with a ClassCastException because the
seq function only works on strings, and you cannot convert
an integer to a string in a straightforward way in Clojure. The
seq function expects its input to be a string or a
collection, such as a vector or a list, and when you try to pass an
integer to it, it will try to convert the integer to a string by calling
the str function on it. However, since str
only works on strings and collections, and not on numbers, this will
result in a ClassCastException.
Here's an example of what will happen if you try to pass an integer
to the reverse-string function:
user=> (reverse-string 12345)
ClassCastException clojure.lang. Numbers cannot be cast to
clojure.lang. IFn clojure.core/seq (core.clj:136)
To avoid this error, you can either make sure that the input to the
reverse-string function is always a string, or you can
modify the function to handle other types of input, such as integers, by
first converting them to strings using the str function.
For example, you could write the reverse-string function
like this to handle both strings and integers as input:
(defn reverse-string [s]
(let [s (if (string? s) s (str s))]
(apply str (reverse (seq s)))))
With this version of the function, if you pass an integer as input,
the function will convert it to a string using the str
function before calling the seq function on it, so the
seq function will be able to work with the input. Here's an
example of how you can use this modified version of the
reverse-string function:
user-> (reverse-string "hello world")
"dlrow olleh"
user=> (reverse-string 12345)
"54321"
Note that the modified version of the function will also work for
other types of input that can be converted to strings using the
str function, such as floats and booleans.
How
would you use the concept of the Maybe monad in Haskell in this clojure
function?
ChatGPT: The Maybe monad in Haskell is a way to
represent computations that may or may not have & p a result, and it
provides a way to compose these computations in a safe and predictable
way. In Clojure, the Maybe monad is usually implemented as a
Option type, which has two possible values:
Some and None
In the context of the reverse-string function, you could
use the Option type to represent the possibility that the
input to the function might not be a string, in which case the function
would return None instead of a reversed string. Here's an
example of how you could use the Option type to modify the
reverse-string function to handle the case where the input
is not a string:
(defn reverse-string [s]
(if (string? s)
(Some (apply str (reverse (seq s))))
None))
With this version of the reverse-string function, if the
input is a string, the function will return a Some value
containing the reversed string, and if the input is not a string, the
function will return a None value. This allows the caller
of the function to handle the case where the input is not a string in a
predictable and safe way.
Here's an example of how you can use this modified version of the
reverse-string function:
user=> (reverse-string "hello world")
Some "dlrow olleh"
user=> (reverse-string 12345)
None
Note that the Option type in Clojure does not provide the same
syntactic sugar for composing computations as the Maybe monad in
Haskell, so you cannot use the >>= operator to chain
calls to the reverse-string function in the same way you
can in Haskell. However, you can still use the Option type
to represent computations that may or may not have a result, and you can
use the match or case forms to pattern match
on the Option values and handle the different cases in a
predictable and safe way.
How
would you implement Option in clojure?
ChatGPT: In Clojure, the Option type is
typically implemented as a sealed protocol, which is a type of
polymorphic type that defines a set of concrete types that implement the
protocol.
The Option protocol typically defines two concrete
types: Some, which represents a computation that has a
result, and None, which represents a computation that does
not have a result.
Here's an example of how you could define the Option
protocol and the Some and None types in
Clojure:
(defprotocol Option
(map [o f])
(flat-map [o f]))
(deftype Some [x]
Option
(map [o f] (Some (f x)))
(flat-map [o f] (f x)))
(deftype None [])
Option
(map [o f] None)
(flat-map [o f] None))
The Option protocol defines two methods:
map and flat-map The map method
takes a function f as input and applies it to the value
contained in the Some type, f it exists, or
returns a None value f the Option
type is None The flat-map method is similar to
map but it allows the function f to return an
Option value, which is then flattened into the outer
Option value.
The Some type implements the Option
protocol by providing concrete implementations f the map
and flat-map methods. The 'map method applies the function
f to the value x contained in the
Some type, and returns a new Some value
containing the result f the function. The
flat-map method applies the function f to the
value x contained in the Some type, and then flattens the
resulting Option value into the outer Option
value.
The None type also implements the Option protocol by
providing concrete implementations of the map and
flat-map methods. The map and
flat-map methods simply return a None value in
this case, since there is no value to apply the function to.
Here's an example of how you can use the Option protocol
and the Some and None types:
user=> (def some-value (Some 12345))
#' user/some-value
user=> (map some-value inc)
Some 12346
user=> (flat-map some-value (fn [x] (Some (* × 2))))
Some 24690
user=> (map some-value (comp (partial * 2) inc))
Some 24690
user=> (def none-value None)
#'user/none-value
user=> (map none-value inc)
None
user=> (flat-map none-value (fn [x] (Some (* × 2))))
None
user=> (map none-value (comp (partial * 2) inc))
None
In this example, the some-value variable is defined as a
Some value containing the integer 12345, and the
none-value variable is defined as a None
value. The map and flat-map functions are then
used to apply different functions to the values contained in the
Option types, and the…