4,875
students have developed their Common Lisp skills on Exercism.

Students
4,875
Submissions
86,734
Mentoring Discussions
2,262

The Common Lisp track needs attention ⚠️

Building

Build

Use your knowledge to build the Common Lisp track itself

Create the Common Lisp syllabus

Learn More

Help create the track syllabus: is a set of concepts and learning exercises put together to teach foundational elements of the programming language.

Next goal: Create a complete syllabus with at least 30 concepts. Find out more.

Usage statistics

27 concepts being taught
Co
Comments
1,078 learnt
Co
Cons
1,078 learnt
Ex
Expressions
1,078 learnt
Sy
Symbols
1,078 learnt
Eq
Equality
179 learnt
Ar
Arithmetic
825 learnt
Fl
Floating Point Numbers
825 learnt
In
Integers
825 learnt
Li
Lists
648 learnt
Co
Conditionals
496 learnt
Tr
Truthy And Falsy
496 learnt
Fu
Functions
464 learnt
Ke
Keyword Parameters
268 learnt
La
Lambda List
268 learnt
Op
Optional Parameters
268 learnt
Re
Rest-Parameters
268 learnt
St
Strings
281 learnt
Ch
Characters
236 learnt
Ar
Arrays
231 learnt
Ve
Vectors
231 learnt
Ha
Hash Tables
220 learnt
Fi
Filtering
210 learnt
Ma
Mapping
210 learnt
Da
Date and Time
233 learnt
Mu
Multiple Values
233 learnt
Re
Reducing
151 learnt
Fo
Format - Basics
148 learnt
15 active learning exercises
Started
Attempts
Completions
Mentoring requests
Sorting Socks and Sexprs Sorting Socks and Sexprs
1,610
9,044 (avg. 5.6)
1,078 (67.0%)
7 (0.4%)
The Key to Comparison The Key to Comparison
188
1,100 (avg. 5.9)
179 (95.2%)
1 (0.5%)
Pizza Pi Pizza Pi
918
9,785 (avg. 10.7)
825 (89.9%)
11 (1.2%)
Leslie's Lengthy Lists Leslie's Lengthy Lists
695
5,543 (avg. 8.0)
648 (93.2%)
9 (1.3%)
Pal Picker Pal Picker
531
5,140 (avg. 9.7)
496 (93.4%)
6 (1.1%)
Lilly's Lasagna Lilly's Lasagna
477
2,642 (avg. 5.5)
464 (97.3%)
2 (0.4%)
Lilly's Lasagna Leftovers Lilly's Lasagna Leftovers
294
3,433 (avg. 11.7)
268 (91.2%)
5 (1.7%)
Log Levels Log Levels
299
2,146 (avg. 7.2)
281 (94.0%)
4 (1.3%)
Character Study Character Study
244
1,198 (avg. 4.9)
236 (96.7%)
1 (0.4%)
Larry's Winning Checker Larry's Winning Checker
257
3,531 (avg. 13.7)
231 (89.9%)
6 (2.3%)
High Scores High Scores
235
1,473 (avg. 6.3)
220 (93.6%)
1 (0.4%)
Lucy's Magnificent Mapper Lucy's Magnificent Mapper
217
870 (avg. 4.0)
210 (96.8%)
2 (0.9%)
Gigasecond Anniversary Gigasecond Anniversary
262
1,965 (avg. 7.5)
233 (88.9%)
1 (0.4%)
Logan's Numeric Partition Logan's Numeric Partition
170
1,834 (avg. 10.8)
151 (88.8%)
3 (1.8%)
Reporting for Duty Reporting for Duty
157
967 (avg. 6.2)
148 (94.3%)
1 (0.6%)

Build Test Runners

Learn More

Create Test Runners that have the single responsibility of taking a solution, running all tests and returning a standardized output.

Next goal: Get Test Runners to Version 3. Common Lisp is currently utilising a Version 2 Test Runner. Find out more.

Usage statistics

Total Test Runner Runs
79,702
Test Run Pass Rate
21.1% (16847)
Test Run Fail Rate
68.6% (54681)
Test Run Error Rate
10.3% (8174)

Build Analyzers

Learn More

Build an Analyzer for Common Lisp: Exercism's analyzers automatically assess student's submissions and provide mentor-style commentary.

Usage statistics

Total Analyzer Runs
14,333
Total Analysis Comments Made
0
Feedback Given Frequency
0.0%

Build Representers

Learn More

Build a Representer: a bit of code that has the single responsibility of taking a solution and returning a normalized representation of it.

Usage statistics

Total Representer Runs
14,359
Total Representation Comments Made
2,161
Feedback Given Frequency
15.0%

Create Practice Exercises

Learn More

Practice Exercises are exercises designed to allow students to solve an arbitrary problem, with the aim of them making use of the concepts they have learned so far.

Next goal: Implement 121 practice exercises. Find out more.

Usage statistics

68 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
3,270
4,343 (avg. 1.3)
2,606 (79.7%)
8 (0.2%)
Two Fer Two Fer
558
1,503 (avg. 2.7)
452 (81.0%)
241 (43.2%)
Hamming Hamming
697
2,000 (avg. 2.9)
585 (83.9%)
362 (51.9%)
RNA Transcription RNA Transcription
415
1,005 (avg. 2.4)
362 (87.2%)
184 (44.3%)
Leap Leap
592
1,507 (avg. 2.5)
557 (94.1%)
243 (41.0%)
Anagram Anagram
271
869 (avg. 3.2)
230 (84.9%)
114 (42.1%)
Beer Song Beer Song
246
1,392 (avg. 5.7)
208 (84.6%)
100 (40.7%)
Roman Numerals Roman Numerals
243
670 (avg. 2.8)
206 (84.8%)
89 (36.6%)
Word Count Word Count
224
823 (avg. 3.7)
174 (77.7%)
93 (41.5%)
Bob Bob
268
829 (avg. 3.1)
221 (82.5%)
137 (51.1%)
Twelve Days Twelve Days
93
324 (avg. 3.5)
79 (84.9%)
8 (8.6%)
Acronym Acronym
251
516 (avg. 2.1)
180 (71.7%)
47 (18.7%)
All Your Base All Your Base
387
2,018 (avg. 5.2)
167 (43.2%)
22 (5.7%)
Allergies Allergies
111
531 (avg. 4.8)
91 (82.0%)
11 (9.9%)
Armstrong Numbers Armstrong Numbers
108
272 (avg. 2.5)
93 (86.1%)
3 (2.8%)
Binary Search Binary Search
82
469 (avg. 5.7)
68 (82.9%)
5 (6.1%)
Collatz Conjecture Collatz Conjecture
278
1,322 (avg. 4.8)
224 (80.6%)
30 (10.8%)
Difference of Squares Difference of Squares
280
1,124 (avg. 4.0)
241 (86.1%)
13 (4.6%)
ETL ETL
141
414 (avg. 2.9)
110 (78.0%)
17 (12.1%)
Grains Grains
364
1,005 (avg. 2.8)
343 (94.2%)
55 (15.1%)
Isogram Isogram
105
261 (avg. 2.5)
90 (85.7%)
14 (13.3%)
Nucleotide Count Nucleotide Count
127
378 (avg. 3.0)
101 (79.5%)
19 (15.0%)
Pascal's Triangle Pascal's Triangle
144
703 (avg. 4.9)
101 (70.1%)
11 (7.6%)
Perfect Numbers Perfect Numbers
120
412 (avg. 3.4)
101 (84.2%)
9 (7.5%)
Raindrops Raindrops
162
370 (avg. 2.3)
134 (82.7%)
28 (17.3%)
Scrabble Score Scrabble Score
101
226 (avg. 2.2)
84 (83.2%)
8 (7.9%)
Sieve Sieve
115
377 (avg. 3.3)
95 (82.6%)
28 (24.3%)
Space Age Space Age
194
657 (avg. 3.4)
163 (84.0%)
26 (13.4%)
Strain Strain
108
194 (avg. 1.8)
95 (88.0%)
11 (10.2%)
Sublist Sublist
278
1,147 (avg. 4.1)
171 (61.5%)
32 (11.5%)
Triangle Triangle
117
370 (avg. 3.2)
94 (80.3%)
14 (12.0%)
Atbash Cipher Atbash Cipher
90
294 (avg. 3.3)
74 (82.2%)
5 (5.6%)
Grade School Grade School
131
396 (avg. 3.0)
97 (74.0%)
23 (17.6%)
Phone Number Phone Number
127
261 (avg. 2.1)
107 (84.3%)
20 (15.7%)
Prime Factors Prime Factors
100
216 (avg. 2.2)
76 (76.0%)
12 (12.0%)
Robot Name Robot Name
185
532 (avg. 2.9)
157 (84.9%)
60 (32.4%)
Robot Simulator Robot Simulator
75
219 (avg. 2.9)
51 (68.0%)
4 (5.3%)
Crypto Square Crypto Square
79
335 (avg. 4.2)
60 (75.9%)
8 (10.1%)
Meetup Meetup
83
378 (avg. 4.6)
59 (71.1%)
8 (9.6%)
Luhn Luhn
181
431 (avg. 2.4)
131 (72.4%)
24 (13.3%)
Book Store Book Store
29
459 (avg. 15.8)
19 (65.5%)
2 (6.9%)
ISBN Verifier ISBN Verifier
31
159 (avg. 5.1)
28 (90.3%)
0 (0.0%)
Sum of Multiples Sum of Multiples
58
219 (avg. 3.8)
47 (81.0%)
2 (3.4%)
Matching Brackets Matching Brackets
57
352 (avg. 6.2)
53 (93.0%)
0 (0.0%)
Run-Length Encoding Run-Length Encoding
22
180 (avg. 8.2)
18 (81.8%)
1 (4.5%)
Largest Series Product Largest Series Product
22
137 (avg. 6.2)
21 (95.5%)
0 (0.0%)
Queen Attack Queen Attack
28
93 (avg. 3.3)
25 (89.3%)
0 (0.0%)
Nth Prime Nth Prime
53
211 (avg. 4.0)
39 (73.6%)
0 (0.0%)
Knapsack Knapsack
19
129 (avg. 6.8)
18 (94.7%)
0 (0.0%)
Rail Fence Cipher Rail Fence Cipher
18
130 (avg. 7.2)
14 (77.8%)
0 (0.0%)
Pig Latin Pig Latin
17
217 (avg. 12.8)
15 (88.2%)
0 (0.0%)
Protein Translation Protein Translation
22
133 (avg. 6.0)
19 (86.4%)
0 (0.0%)
Saddle Points Saddle Points
24
93 (avg. 3.9)
19 (79.2%)
0 (0.0%)
Matrix Matrix
20
102 (avg. 5.1)
17 (85.0%)
0 (0.0%)
Palindrome Products Palindrome Products
24
207 (avg. 8.6)
18 (75.0%)
0 (0.0%)
Pythagorean Triplet Pythagorean Triplet
25
177 (avg. 7.1)
19 (76.0%)
1 (4.0%)
Affine Cipher Affine Cipher
18
242 (avg. 13.4)
15 (83.3%)
0 (0.0%)
Say Say
20
37 (avg. 1.9)
17 (85.0%)
0 (0.0%)
Two Bucket Two Bucket
19
160 (avg. 8.4)
13 (68.4%)
2 (10.5%)
Flatten Array Flatten Array
23
67 (avg. 2.9)
23 (100.0%)
0 (0.0%)
Spiral Matrix Spiral Matrix
20
94 (avg. 4.7)
18 (90.0%)
0 (0.0%)
Diamond Diamond
14
114 (avg. 8.1)
13 (92.9%)
0 (0.0%)
Rotational Cipher Rotational Cipher
27
66 (avg. 2.4)
24 (88.9%)
0 (0.0%)
Pangram Pangram
25
83 (avg. 3.3)
24 (96.0%)
0 (0.0%)
Secret Handshake Secret Handshake
32
128 (avg. 4.0)
30 (93.8%)
0 (0.0%)
Darts Darts
78
337 (avg. 4.3)
71 (91.0%)
0 (0.0%)
Proverb Proverb
21
88 (avg. 4.2)
21 (100.0%)
0 (0.0%)
Food Chain Food Chain
15
106 (avg. 7.1)
12 (80.0%)
0 (0.0%)
3 deprecated practice exercises
Started
Attempts
Completions
Mentoring requests
Binary Binary
71
138 (avg. 1.9)
56 (78.9%)
12 (16.9%)
Gigasecond Gigasecond
176
227 (avg. 1.3)
147 (83.5%)
40 (22.7%)
Trinary Trinary
59
85 (avg. 1.4)
47 (79.7%)
8 (13.6%)
53 unimplemented practice exercises
Alphametics Alphametics
Binary Search Tree Binary Search Tree
Bottle Song Bottle Song
Bowling Bowling
Change Change
Circular Buffer Circular Buffer
Clock Clock
Complex Numbers Complex Numbers
Connect Connect
Custom Set Custom Set
D&D Character D&D Character
DOT DSL DOT DSL
Dominoes Dominoes
Error Handling Error Handling
Forth Forth
Go Counting Go Counting
Grep Grep
Hangman Hangman
High Scores High Scores
House House
Killer Sudoku Helper Killer Sudoku Helper
Kindergarten Garden Kindergarten Garden
Ledger Ledger
Markdown Markdown
Micro Blog Micro Blog
Minesweeper Minesweeper
OCR Numbers OCR Numbers
POV POV
PaaS I/O PaaS I/O
Poker Poker
REST API REST API
Rational Numbers Rational Numbers
React React
Rectangles Rectangles
Resistor Color Resistor Color
Resistor Color Duo Resistor Color Duo
Resistor Color Trio Resistor Color Trio
SGF Parsing SGF Parsing
Satellite Satellite
Scale Generator Scale Generator
Series Series
Simple Cipher Simple Cipher
Square Root Square Root
State of Tic-Tac-Toe State of Tic-Tac-Toe
Tournament Tournament
Transpose Transpose
Tree Building Tree Building
Variable Length Quantity Variable Length Quantity
Word Search Word Search
Wordy Wordy
Yacht Yacht
Zebra Puzzle Zebra Puzzle
Zipper Zipper
8 foregone practice exercises
Accumulate Accumulate
Bank Account Bank Account
Lens Person Lens Person
Linked List Linked List
List Ops List Ops
Parallel Letter Frequency Parallel Letter Frequency
Reverse String Reverse String
Simple Linked List Simple Linked List