Common Lisp Training

Exercises from a functional programming course in Common Lisp: recursion over lists, closures, higher-order functions, macros, CLOS state machines and a small expression parser.

Year: 2020 · Language: Common Lisp (SBCL) · Context: university coursework (KPI)

What's inside

Folder names are kept exactly as committed (some contain spaces and parentheses, so quote them in a shell).

Folder	What it does
lecture-1/	my-flatten, compose (two implementations)
lecture-6/	Convert a string to a hash table and back
lecture-9(awhen aif..)/	Anaphoric macros awhen, aif and a cut macro (partial application with _ placeholders)
home-task-1/	List basics: sum, inc-list, tail-recursive my-reverse, my-delete-repeats
home-task-2/	Bubble, selection and insertion sort, imperative and recursive versions
home-task-3/	Sets as predicate closures: create-set, my-union, my-intersect, my-difference
home-task-4/	merge-strings (interleave), archieve-string (run-length encoding, aaaab -> a4b)
home-task-5/	Mini SQL-like select over three text tables (table1-3.txt: people, buses, links) with make-select, in list and hash-table versions; results in res1-3.txt
home-task-6/	Lexer + recursive parser + printer for arithmetic expressions
practice-1/	my-remove, find-best-element, make-mapcar-if, assoc-member, my-reduce with :key, :test, :from-end, :initial-value
practice-2/	n-way merge-strings, greatest common substring, shortest path down a number triangle (res.txt is a generated triangle), greatest palindrome
practice-4(CLOS)/	State-machine framework in CLOS; instances: conditioner, hair drier, coffee machine
practice-5 (our-let my-or...)/	Macros our-let, our-let*, my-or, alambda
practice-6(with-gensyms, aand...)/	Macros with-gensyms, aand, acond, mv-let*
control-task/	Control work: n-ary tree (defstruct node), traversals, map-tree, expression evaluation

Interesting bits

• home-task-6/task6.lisp parses arithmetic with nested helper functions inside labels; tests show it drops redundant parentheses ("((3 - 2)) - 1" prints as "3 - 2 - 1").
• control-task/control-task-ivanenko.lisp builds a tree from a Lisp form ((+ 1 2 (* 3 4 5))), offers pre-order, post-order and breadth-first walks with :key and :mod callbacks, and evaluates the tree by apply-ing the node symbol to its evaluated children.
• practice-4(CLOS)/task.lisp (about 640 lines) uses :before / :after methods on nextstate and send, and generic handle-signal dispatch on state and signal classes; its default method reports unsupported signals.
• lecture-9(awhen aif..)/task.lisp cut expands (cut lst a (_ (_)) d _) into a lambda with one gensym per _.

Run

Verified with SBCL 2.2.9: each file loads cleanly. The test functions print only on failure; with them all were silent (no mismatch):

sbcl --noinform --non-interactive --load control-task/control-task-ivanenko.lisp --eval "(tests)"
cd home-task-1 && sbcl --noinform --non-interactive --load work.lisp --eval "(test-all)"

Test entry points differ by file (tests, test-all, all-tests); check the end of each file. home-task-5 reads and writes its .txt files in the current directory, so run it from inside that folder.

Note

Written in 2020, before AI coding assistants. Kept as-is for history.