Common Lisp, or ANSI Common Lisp, is a standardized version of the Lisp programming language intended for production-strength power and libraries.
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Unit test macro [on hold]
I have written a couple of macros (? and ??) for performing unit tests, but I'm having some difficulty with modifying it, so I ...
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1answer
89 views
Producing all allocations by n items from a list
I have strong feeling that the code below is ugly at least as there are 2 same "cons".
I would appreciate if you advise me ways to improve it.
The code produces all allocation by n items from list ...
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4answers
256 views
Generic sequence splitter in Common Lisp
I wrote a function split-seq-by-n which accepts a sequence and a number and splits the sequence into subsequences of length n (the last subsequence getting the ...
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2answers
41 views
“Skewed” average in Lisp
I set myself the task to calculate the average of a list, but with two conditions:
negative numbers are ignored
numbers greater than 100 are counted as if they were 100
So the "skewed" average of ...
3
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1answer
31 views
Insertion sort in Common Lisp
This is my first bit of significant code in Common Lisp, an implementation of insertion sort. Being new to Lisp in general, I'm wondering if this code follows best Lisp practices in regards to program ...
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2answers
42 views
Standard deviation of hourly temperatures of 2 days
It seems that when I program in Lisp my brain goes on auto pilot and I end up solving the problem somehow. I don't even think I just do and it works out.
That said, this is some horrible Lisp code ...
5
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1answer
36 views
Finding capitalized characters and printing their position & ASCII value
I was trying to find out if a string contained a capitalized letter and if it did I wanted to know the position of the character and its ASCII code. I might have refactored a little to much.
Given an ...
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1answer
577 views
Solving the 'Vietnamese school maths problem'
Having read Can you do the maths puzzle for Vietnamese eight-year-olds that has stumped parents and teachers?, which presented the problem of filling in numbers 1 to 9 to satisfy
$$ a + 13 ...
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77 views
Functional tree iteration in Common Lisp
I'm adding some functionality to an existing library of data structures in Common Lisp, with a view to asking the original author if I can take over maintenance and development of it. While the ...
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1answer
251 views
Determinant calculation of a matrix of any degree
My program calculates the determinant of a matrix of any degree. If you really can't understand my comments or indentifiers please let me know.
...
5
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1answer
154 views
ANFIS network based on Sugeno model I
I've been learning Common Lisp lately and I've implemented ANFIS network based on Sugeno model I.
Network layout and details can be read in these slides by Adriano Oliveira Cruz.
I use sigmoid as the ...
2
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1answer
179 views
Project Euler #35 in Common Lisp
To start with Common Lisp I am doing Project Euler using this language. Usually I manage to solve problems but I am quite sure that my code is not as efficient as it could be in Common Lisp. That is ...
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3answers
119 views
Recursion vs. iteration in Lisp macro
I've been programming Clojure for a little while and recently started learning Common Lisp. One of my favorite things about Clojure is the threading operator ->, ...
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2answers
121 views
Creating a repetitive string in Common Lisp
I needed to have a Lisp function that could produce a string of a certain length, created by repeated concatenations of a another string given as argument (so for example by giving 10 and "abc" I ...
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2answers
93 views
Using reduce twice in a row for Run Length Encoding
First of all, I'm new to Lisp (I currently use CLISP and SBCL). There probably are huge mistakes in this code so any guidelines are welcome :)
I'm very confused about how to do this. It's just about ...
6
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4answers
181 views
FizzBuzz - officially now in CLISP
I had to jump on the bandwagon for this one. The task does a great job of helping you learn a language you're unfamiliar with.
So today I present you with my version of the infamous FizzBuzz game in ...
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2answers
98 views
Written numbers to numerical representation
So I took a stab at this task to begin learning common lisp.
The idea is that you give it a written representation of a number such as "three thousand and forty nine" and it will output 3049.
I was ...
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3answers
587 views
Calculate the weekday from a date (M-D-Y)
This Common Lisp exercise is to write a program that can calculate the weekday given a string of the format "M-D-Y." It was more challenging than I expected. If you have suggestions about how to ...
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2answers
455 views
Determining if f(n) = n^2 + 3n + 5 is ever divisible by 121
Given the following problem:
It is conjectured that for any \$n > 0\$, \$n^2 + 3n + 5\$ is never
divisible by 121. Test this conjecture for \$n = 1,2,...,9999,10000\$.
I wrote the following ...
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1answer
559 views
Finding a cryptoarithmetic solution
This code is intended to find all possible solutions to a cryptoarithmetic problem. The description of the problem I was trying to solve is here:
In cryptoarithmetic problems, we are given a ...
4
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3answers
2k views
Lisp quicksort code
I would really appreciate it if someone could review my quicksort implementation. Additionally, I generated my list dynamically and wrote a couple of tests. Of course, I realize that the tests are ...
2
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2answers
1k views
Testing input integers for the palindrome property
3.23 Palindromes
A palindrome is a number that reads the same forwards
and backwards, like 12321. Write a
program that tests input integers for
the palindrome property.
Hint: This ...
2
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1answer
246 views
Compute arithmetic sum of a constant difference sequence
3.1
Write a program that computes the arithmetic sum of a constant
difference sequence:
D0 = A
Dn+1 = Cdn + B
Run the following values and compare ...
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1answer
317 views
Abstract the (duplicate?) behavior between “sort” and “replace”
I have written these two functions that have a similar process. The first is meant to "split" a string on a given character and the second is meant to "replace-all" instances of a character in a ...
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1answer
92 views
Tabulate k = 2^n minimizing multiplication
Given the following problem:
;3.3 Tabulate the function k = 2^n for n = 1..50.
;Do this for the fewest possible multiplications.[3]
I wrote this answer:
...
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1answer
170 views
Machine epsilon - find epsi
4.2 Machine Epsilon
Find the floating point number epsi that has
the the following properties:
1.0+epsi is greater than 1.0 and
Let m b e any number less than epsi. Then 1.0+m is ...
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2answers
2k views
Print an integer and its digits reversed
This Common Lisp program is an exercise to print an integer and its digits reversed to the screen:
...
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1answer
96 views
Rewrite apply function to use recursion instead
Probably the hardest part of learning lisp has been to think in the "lisp way" which is elegant and impressive, but not always easy. I know that recursion is used to solve a lot of problems, and I am ...
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1answer
134 views
First Common Lisp vector math code
I'm studying Common Lisp on my own. Coming from C++, Common Lisp feels kind of strange sometimes. I'd like to get some feedback on what I understood so far.
For learning purposes, I wrote this simple ...
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1answer
152 views
Generating hard to guess session tokens
Does this code create sufficiently hard-to-guess session tokens, assuming the server and client are communicating over HTTPS?
Take 2 (thanks to this crypto.SE answer):
...
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4answers
1k views
Finding the sum of all the multiples of 3 or 5 below 1000
As a Lisp (and functional programming) newbie, I wrote the following code that finds the sum of all the multiples of 3 or 5 below 1000, and I suspect that it is lousy:
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1answer
166 views
Did I convert this C++ class to Common Lisp correctly?
Here is the original C++ class I converted to Lisp at the very bottom of this post.
...
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1answer
432 views
Simple octal reader macro in Common Lisp
As an exercise, I've implemented a simple reader macro in Common Lisp (using SBCL). It converts Octal (unsigned integers only) into numbers.
Usage:
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1answer
53 views
Finding optimal row sequence for a melody on 5-row Bayan Accordion, v2.0
Another try at this problem in LISP. This time rather than generating every possible row combination for the melody I tried to calculate the best combination directly. Unfortunately there's a problem ...
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232 views
iterative copy-tree in lisp
The common lisp function copy-tree is often implemented in a recursive way,
and thus is prone to stack overflow.
Here is my attempt at writing an iterative version, one-pass, no stack,
no ...
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2answers
63 views
Calculating series of rows to use to play a melody on 5-row Bayan Accordion
This was my first attempt at writing a program in LISP. Can anyone give any guides as to how it could be improved? The multiple loops in best-pattern seem awkward (I'd normally do that in just one ...
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2answers
65 views
Is using defvar for a non-global variable ok?
I am calling defvar in the middle of a function definition. And so far I've always seen its use, with defparameter for global ...
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1answer
165 views
common lisp: nested loop beautification (checkboard texture generator)
I've written a small code snippet that generates checkboard texture using cl-opengl.
...
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4answers
2k views
Finite State Machine code
I have been making this FSM today. However, as this is probably the biggest practical program I have ever written in CL, I don't know if there are some things that could be improved, or if using a ...
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1answer
386 views
Prime test - style and correct idiom review please
Below is some code I've created to generate and use a list of prime numbers. This is some of the first common lisp code I've written, and I'd be grateful for any comments regarding style and its use ...
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5answers
828 views
Determine type of triangle in LISP
This is a simple LISP program to read in three sides of a triangle and report what kind of triangle it is (or isn't). Any feedback would be much appreciated.
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1answer
200 views
LISP - Modify string
I have to write a program that changes a string's vowels, consonants and other symbols into C, V respectively 0. I've done this but I wonder if there is a more efficient and elegant way to do it. ...
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2answers
325 views
Improving readability of non-recursive depth first search function in Lisp
As a free-time activity in order to learn some Lisp I had to implement depth first directed graph search. Due to large graph size (800K nodes, 5M arcs) recursion-based approach I could devise didn't ...
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1answer
285 views
Proper use of reduce, nested loops
Below is an implementation of Dijkstra's shortest path algorithm. It's input graph is represented as an association list of source nodes to assoc of target node and ...
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1answer
124 views
How to improve readability of a big lisp function
My main method (remove-random-edge) looks quite difficult to read. I'm new to list, so would appreciate any advice on how to improve the code.
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1answer
147 views
Seeking advice on lispiness of style and approach
I'm new to Lisp and I'm yet to wrap my head around the Lisp way of writing programs. Any comments regarding approach, style, missed opportunities appreciated:
In particular, please advice if I build ...
2
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1answer
310 views
Simplify complex hash-table manipulations in Common Lisp
I'm trying to write a simple triplestore in Common Lisp that will store triples in the form subject-predicate-object. The code is inspired by the book "Programming the Semantic Web".
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1answer
222 views
Sundaram's sieve in Common Lisp
I have this Sundaram's sieve to generate prime numbers up to limit in Common Lisp.
...
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2answers
193 views
2
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1answer
226 views
Message queues in Common Lisp
General advice for a change. This is an implementation of message queues that I'm going to use for some work on an actors model library.
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