Add 4 new Common Lisp exercises

common-lisp/isbn-verifier/.exercism/config.json

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+{
+  "authors": [
+    "PaulT89"
+  ],
+  "files": {
+    "solution": [
+      "isbn-verifier.lisp"
+    ],
+    "test": [
+      "isbn-verifier-test.lisp"
+    ],
+    "example": [
+      ".meta/example.lisp"
+    ]
+  },
+  "blurb": "Check if a given string is a valid ISBN-10 number.",
+  "source": "Converting a string into a number and some basic processing utilizing a relatable real world example.",
+  "source_url": "https://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digit_calculation"
+}

common-lisp/isbn-verifier/.exercism/metadata.json

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+{"track":"common-lisp","exercise":"isbn-verifier","id":"15547c7317a04ba0ba72f69af94e25d7","url":"https://exercism.org/tracks/common-lisp/exercises/isbn-verifier","handle":"wsgac","is_requester":true,"auto_approve":false}

common-lisp/isbn-verifier/HELP.md

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+# Help
+
+## Running the tests
+
+Start the REPL from the directory that you downloaded the exercise to.
+
+You can run the tests by loading the test file into the REPL with `(load "exercise-test")` (replacing "exercise" with appropriate name). Then evaluate `(exercise-test:run-tests)` to run all the tests.
+
+If you write your code directly in the REPL then simply evaluate `(exercise-test:run-tests)`.
+
+If you write your code in the exercise lisp file then load it with `(load "exercise")` then evaluate `(exercise-test:run-tests)`.
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit isbn-verifier.lisp` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Common Lisp track's documentation](https://exercism.org/docs/tracks/common-lisp)
+- The [Common Lisp track's programming category on the forum](https://forum.exercism.org/c/programming/common-lisp)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+## Setup
+
+Check out [Installing Common
+Lisp][track-install] for
+instructions to get started or take a look at the guides available in
+the [track's documentation pages][track-docs].
+
+## Where to look for help
+
+Any of the resources listed in the list of [Useful Common Lisp Resources][track-resources] are good places to look for information.
+
+There are also some [Online Communities][awesome-cl-communities] which may be good places to go for help.
+
+## Formatting
+
+While Common Lisp doesn't care about indentation and layout of code,
+nor whether you use spaces or tabs, this is an important consideration
+for submissions to exercism.
+Exercism.org's code widget cannot handle mixing of tab and space characters well so using only spaces is recommended to make
+the code more readable to the human reviewers.
+Please review your editors settings on how to accomplish this.
+Below are instructions for popular editors for Common Lisp.
+
+### VIM
+
+Use the following commands to ensure VIM uses only spaces for
+indentation:
+
+```vimscript
+:set tabstop=2
+:set shiftwidth=2
+:set expandtab
+```
+
+(or as a oneliner `:set tabstop=2 shiftwidth=2 expandtab`). This can
+be added to your `~/.vimrc` file to use it all the time.
+
+### Emacs
+
+Emacs is very well suited for editing Common Lisp and has many
+powerful add-on packages available. The only thing that one needs to
+do with a stock emacs to make it work well with exercism.org is to
+evaluate the following code:
+
+`(setq-default indent-tabs-mode nil)`
+
+This can be placed in your `~/.emacs` (or `~/.emacs.d/init.el`) in
+order to have it set whenever Emacs is launched.
+
+One suggested add-on for Emacs and Common Lisp is
+[SLIME][slime] which offers tight integration
+with the REPL; making iterative coding and testing very easy.
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can ask for mentoring to help you come to the correct solution.
+
+[awesome-cl-communities]: https://github.com/GustavBertram/awesome-common-lisp-learning#online-community
+[slime]: https://github.com/slime/slime
+[track-docs]: /docs/tracks/common-lisp
+[track-install]: /docs/tracks/common-lisp/installation
+[track-resources]: /docs/tracks/common-lisp/resources

common-lisp/isbn-verifier/README.md

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+# ISBN Verifier
+
+Welcome to ISBN Verifier on Exercism's Common Lisp Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+The [ISBN-10 verification process][isbn-verification] is used to validate book identification numbers.
+These normally contain dashes and look like: `3-598-21508-8`
+
+## ISBN
+
+The ISBN-10 format is 9 digits (0 to 9) plus one check character (either a digit or an X only).
+In the case the check character is an X, this represents the value '10'.
+These may be communicated with or without hyphens, and can be checked for their validity by the following formula:
+
+```text
+(d₁ * 10 + d₂ * 9 + d₃ * 8 + d₄ * 7 + d₅ * 6 + d₆ * 5 + d₇ * 4 + d₈ * 3 + d₉ * 2 + d₁₀ * 1) mod 11 == 0
+```
+
+If the result is 0, then it is a valid ISBN-10, otherwise it is invalid.
+
+## Example
+
+Let's take the ISBN-10 `3-598-21508-8`.
+We plug it in to the formula, and get:
+
+```text
+(3 * 10 + 5 * 9 + 9 * 8 + 8 * 7 + 2 * 6 + 1 * 5 + 5 * 4 + 0 * 3 + 8 * 2 + 8 * 1) mod 11 == 0
+```
+
+Since the result is 0, this proves that our ISBN is valid.
+
+## Task
+
+Given a string the program should check if the provided string is a valid ISBN-10.
+Putting this into place requires some thinking about preprocessing/parsing of the string prior to calculating the check digit for the ISBN.
+
+The program should be able to verify ISBN-10 both with and without separating dashes.
+
+## Caveats
+
+Converting from strings to numbers can be tricky in certain languages.
+Now, it's even trickier since the check digit of an ISBN-10 may be 'X' (representing '10').
+For instance `3-598-21507-X` is a valid ISBN-10.
+
+[isbn-verification]: https://en.wikipedia.org/wiki/International_Standard_Book_Number
+
+## Source
+
+### Created by
+
+- @PaulT89
+
+### Based on
+
+Converting a string into a number and some basic processing utilizing a relatable real world example. - https://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digit_calculation

common-lisp/isbn-verifier/isbn-verifier-test.lisp

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+;; Ensures that isbn-verifier.lisp and the testing library are always loaded
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (load "isbn-verifier")
+  (quicklisp-client:quickload :fiveam))
+
+;; Defines the testing package with symbols from isbn-verifier and FiveAM in scope
+;; The `run-tests` function is exported for use by both the user and test-runner
+(defpackage :isbn-verifier-test
+  (:use :cl :fiveam)
+  (:export :run-tests))
+
+;; Enter the testing package
+(in-package :isbn-verifier-test)
+
+;; Define and enter a new FiveAM test-suite
+(def-suite* isbn-verifier-suite)
+
+(test valid-isbn
+    (let ((isbn "3-598-21508-8"))
+      (is-true (isbn-verifier:validp isbn))))
+
+(test invalid-isbn-check-digit
+    (let ((isbn "3-598-21508-9"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test valid-isbn-with-a-check-digit-of-10
+    (let ((isbn "3-598-21507-X"))
+      (is-true (isbn-verifier:validp isbn))))
+
+(test check-digit-is-a-character-other-than-x
+    (let ((isbn "3-598-21507-A"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test invalid-check-digit-in-isbn-is-not-treated-as-zero
+    (let ((isbn "4-598-21507-B"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test invalid-character-in-isbn-is-not-treated-as-zero
+    (let ((isbn "3-598-P1581-X"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test x-is-only-valid-as-a-check-digit
+    (let ((isbn "3-598-2X507-9"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test valid-isbn-without-separating-dashes
+    (let ((isbn "3598215088"))
+      (is-true (isbn-verifier:validp isbn))))
+
+(test isbn-without-separating-dashes-and-x-as-check-digit
+    (let ((isbn "359821507X"))
+      (is-true (isbn-verifier:validp isbn))))
+
+(test isbn-without-check-digit-and-dashes
+    (let ((isbn "359821507"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test too-long-isbn-and-no-dashes
+    (let ((isbn "3598215078X"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test too-short-isbn
+    (let ((isbn "00"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test isbn-without-check-digit
+    (let ((isbn "3-598-21507"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test check-digit-of-x-should-not-be-used-for-0
+    (let ((isbn "3-598-21515-X"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test empty-isbn
+    (let ((isbn ""))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test input-is-9-characters
+    (let ((isbn "134456729"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test invalid-characters-are-not-ignored-after-checking-length
+    (let ((isbn "3132P34035"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test invalid-characters-are-not-ignored-before-checking-length
+    (let ((isbn "3598P215088"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(test input-is-too-long-but-contains-a-valid-isbn
+    (let ((isbn "98245726788"))
+      (is-false (isbn-verifier:validp isbn))))
+
+(defun run-tests (&optional (test-or-suite 'isbn-verifier-suite))
+  "Provides human readable results of test run. Default to entire suite."
+  (run! test-or-suite))

common-lisp/isbn-verifier/isbn-verifier.lisp

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+(defpackage :isbn-verifier
+  (:use :cl)
+  (:export :validp))
+
+(in-package :isbn-verifier)
+
+(define-condition invalid-character (error)
+  ())
+
+(defun char-to-number (c i)
+  (cond
+    ((char<= #\0 c #\9)
+     (- (char-code c) (char-code #\0)))
+    ((and (char-equal c #\x) (= i 10)) 10)
+    ((char-equal c #\-) nil)
+    (t (error 'invalid-character))))
+
+(defun validp (isbn)
+  (handler-case (loop
+		  with i = 1
+		  for c in (coerce isbn 'list)
+		  for cc = (char-to-number c i)
+		  if cc
+		    do (incf i)
+		    and collect cc into digits
+		  finally (return (and (= 10 (length digits))
+				       (zerop (mod (loop
+						     for d in digits
+						     for i from 10 downto 1
+						     sum (* d i)) 11)))))
+    (invalid-character ()
+      nil)))

common-lisp/matching-brackets/.exercism/config.json

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+{
+  "authors": [
+    "PaulT89"
+  ],
+  "contributors": [
+    "verdammelt"
+  ],
+  "files": {
+    "solution": [
+      "matching-brackets.lisp"
+    ],
+    "test": [
+      "matching-brackets-test.lisp"
+    ],
+    "example": [
+      ".meta/example.lisp"
+    ]
+  },
+  "blurb": "Make sure the brackets and braces all match.",
+  "source": "Ginna Baker"
+}

common-lisp/matching-brackets/.exercism/metadata.json

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+{"track":"common-lisp","exercise":"matching-brackets","id":"4a62f984a53c42ea8d6e4ab6ed08a8a1","url":"https://exercism.org/tracks/common-lisp/exercises/matching-brackets","handle":"wsgac","is_requester":true,"auto_approve":false}