diff --git a/Krivonosov/.gitignore b/Krivonosov/.gitignore
new file mode 100644
index 00000000..e6d7abd6
--- /dev/null
+++ b/Krivonosov/.gitignore
@@ -0,0 +1,7 @@
+_build
+_coverage
+/_esy
+/node_modules
+/esy.lock
+/.melange.eobjs
+check-ci.sh
diff --git a/Krivonosov/.ocamlformat b/Krivonosov/.ocamlformat
new file mode 100644
index 00000000..97f97080
--- /dev/null
+++ b/Krivonosov/.ocamlformat
@@ -0,0 +1,2 @@
+profile=janestreet
+version=0.26.2
diff --git a/Krivonosov/.zanuda b/Krivonosov/.zanuda
new file mode 100644
index 00000000..39f42da0
--- /dev/null
+++ b/Krivonosov/.zanuda
@@ -0,0 +1 @@
+forward mutability_check ignore REPL.ml
\ No newline at end of file
diff --git a/Krivonosov/COPYING b/Krivonosov/COPYING
new file mode 100644
index 00000000..f288702d
--- /dev/null
+++ b/Krivonosov/COPYING
@@ -0,0 +1,674 @@
+ GNU GENERAL PUBLIC LICENSE
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+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
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+
+ 16. Limitation of Liability.
+
+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
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+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
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+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
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+ This program is distributed in the hope that it will be useful,
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+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
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+ This is free software, and you are welcome to redistribute it
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+ You should also get your employer (if you work as a programmer) or school,
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diff --git a/Krivonosov/COPYING.CC0 b/Krivonosov/COPYING.CC0
new file mode 100644
index 00000000..0e259d42
--- /dev/null
+++ b/Krivonosov/COPYING.CC0
@@ -0,0 +1,121 @@
+Creative Commons Legal Code
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diff --git a/Krivonosov/COPYING.LESSER b/Krivonosov/COPYING.LESSER
new file mode 100644
index 00000000..0a041280
--- /dev/null
+++ b/Krivonosov/COPYING.LESSER
@@ -0,0 +1,165 @@
+ GNU LESSER GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc.
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
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+
+ This version of the GNU Lesser General Public License incorporates
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diff --git a/Krivonosov/Krivonosov.opam b/Krivonosov/Krivonosov.opam
new file mode 100644
index 00000000..0464cd06
--- /dev/null
+++ b/Krivonosov/Krivonosov.opam
@@ -0,0 +1,41 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+version: "0.1"
+synopsis: "An interpreter for mimiML"
+description:
+ "A Call-by-Value miniML interpreter featuring recursion, arithmetic, and monadic error handling"
+maintainer: ["Krivonosov Konstantin "]
+authors: ["Krivonosov Konstantin "]
+license: "LGPL-3.0-or-later WITH OCaml-LGPL-linking-exception"
+homepage: "https://github.com/Kakadu/fp25"
+doc: "https://kakadu.github.io/fp25/docs/Krivonosov"
+bug-reports: "https://github.com/Kakadu/fp25"
+depends: [
+ "dune" {>= "3.7" & = "3.19.1"}
+ "angstrom" {= "0.16.0"}
+ "base"
+ "stdio"
+ "ppx_inline_test" {with-test}
+ "ppx_expect"
+ "ppx_deriving"
+ "bisect_ppx"
+ "qcheck" {with-test}
+ "qcheck-core" {with-test}
+ "odoc" {with-doc}
+ "ocamlformat" {build & = "0.26.2"}
+]
+build: [
+ ["dune" "subst"] {dev}
+ [
+ "dune"
+ "build"
+ "-p"
+ name
+ "-j"
+ jobs
+ "@install"
+ "@runtest" {with-test}
+ "@doc" {with-doc}
+ ]
+]
+# Don't edit '*.opam' file manually. Use 'dune b @install'
diff --git a/Krivonosov/Krivonosov.opam.template b/Krivonosov/Krivonosov.opam.template
new file mode 100644
index 00000000..83c4847c
--- /dev/null
+++ b/Krivonosov/Krivonosov.opam.template
@@ -0,0 +1 @@
+# Don't edit '*.opam' file manually. Use 'dune b @install'
diff --git a/Krivonosov/Makefile b/Krivonosov/Makefile
new file mode 100644
index 00000000..04067551
--- /dev/null
+++ b/Krivonosov/Makefile
@@ -0,0 +1,49 @@
+.PHONY: repl tests test fmt lint celan
+
+all:
+ dune build
+
+repl:
+ dune build bin/REPL.exe && rlwrap _build/default/bin/REPL.exe
+
+tests: test
+test:
+ dune runtest
+
+celan: clean
+clean:
+ @$(RM) -r _build _coverage
+
+fmt:
+ dune build @fmt --auto-promote
+
+lint:
+ dune build @lint --force
+
+release:
+ dune build --profile=release
+ dune runtest --profile=release
+
+install:
+ dune b @install --profile=release
+ dune install
+
+ODIG_SWITCHES = --odoc-theme=odig.gruvbox.light
+ODIG_SWITCHES += --no-tag-index
+ODIG_SWITCHES += --no-pkg-deps
+odig:
+ odig odoc $(ODIG_SWITCHES) Lambda
+
+TEST_COV_D = /tmp/cov
+COVERAGE_OPTS = --coverage-path $(TEST_COV_D)
+
+.PHONY: test_coverage coverage
+test_coverage: coverage
+coverage:
+ $(RM) -r $(TEST_COV_D)
+ mkdir -p $(TEST_COV_D)
+ BISECT_FILE=$(TEST_COV_D)/language dune runtest --no-print-directory \
+ --instrument-with bisect_ppx --force
+ bisect-ppx-report html $(COVERAGE_OPTS)
+ bisect-ppx-report summary $(COVERAGE_OPTS)
+ @echo "Use 'xdg-open _coverage/index.html' to see coverage report"
diff --git a/Krivonosov/bin/REPL.ml b/Krivonosov/bin/REPL.ml
new file mode 100644
index 00000000..7561258d
--- /dev/null
+++ b/Krivonosov/bin/REPL.ml
@@ -0,0 +1,59 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Base
+open Stdio
+open Lambda_lib
+open Lambda_lib.Interpret
+
+(** Parse command line arguments*)
+let parse_args args =
+ let rec parse max_steps = function
+ | [] -> Some max_steps
+ | "-max-steps" :: n :: rest ->
+ (match Stdlib.int_of_string_opt n with
+ | Some steps -> parse steps rest
+ | None ->
+ eprintf "Error: Invalid value for -max-steps: %s\n" n;
+ None)
+ | arg :: _ ->
+ eprintf "Error: Unknown argument: %s\n" arg;
+ None
+ in
+ match parse 10000 args with
+ | Some max_steps -> max_steps
+ | None -> Stdlib.exit 1
+;;
+
+let () =
+ let max_steps = parse_args (List.tl_exn (Array.to_list (Sys.get_argv ()))) in
+ let input = In_channel.input_all In_channel.stdin |> String.strip in
+ match Parser.parse input with
+ | Error e ->
+ let msg = Stdlib.Format.asprintf "%a" Parser.pp_error e in
+ eprintf "Error: %s\n" msg;
+ Stdlib.exit 1
+ | Result.Ok ast ->
+ (match eval_expr ~max_steps ast with
+ | Result.Ok (VInt n) -> printf "%d\n" n
+ | Result.Ok (VClosure _) -> printf "\n"
+ | Result.Ok (VBuiltin (name, _)) -> printf "\n" name
+ | Result.Ok VUnit -> printf "()\n"
+ | Result.Error (UnknownVariable name) ->
+ eprintf "Unbound variable: %s\n" name;
+ Stdlib.exit 1
+ | Result.Error DivisionByZero ->
+ eprintf "Division by zero\n";
+ Stdlib.exit 1
+ | Result.Error TypeMismatch ->
+ eprintf "Type error\n";
+ Stdlib.exit 1
+ | Result.Error StepLimitExceeded ->
+ eprintf "Step limit exceeded\n";
+ Stdlib.exit 1)
+;;
diff --git a/Krivonosov/bin/REPL.mli b/Krivonosov/bin/REPL.mli
new file mode 100644
index 00000000..8fff234c
--- /dev/null
+++ b/Krivonosov/bin/REPL.mli
@@ -0,0 +1,7 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
diff --git a/Krivonosov/bin/dune b/Krivonosov/bin/dune
new file mode 100644
index 00000000..b61cc285
--- /dev/null
+++ b/Krivonosov/bin/dune
@@ -0,0 +1,10 @@
+(executable
+ (name REPL)
+ (public_name REPL)
+ (modules REPL)
+ (libraries lambda_lib base stdio)
+ (instrumentation
+ (backend bisect_ppx)))
+
+(cram
+ (deps ./REPL.exe %{bin:REPL}))
diff --git a/Krivonosov/dune b/Krivonosov/dune
new file mode 100644
index 00000000..98e54536
--- /dev/null
+++ b/Krivonosov/dune
@@ -0,0 +1,7 @@
+(env
+ (dev
+ (flags
+ (:standard -alert @deprecated -warn-error -A -w -3-9-32-34-58)))
+ (release
+ (flags
+ (:standard -alert @deprecated -warn-error +A -w +A-4-40-42-44-70))))
diff --git a/Krivonosov/dune-project b/Krivonosov/dune-project
new file mode 100644
index 00000000..6dea837a
--- /dev/null
+++ b/Krivonosov/dune-project
@@ -0,0 +1,44 @@
+(lang dune 3.7)
+
+(generate_opam_files true)
+
+(cram enable)
+
+(license "LGPL-3.0-or-later WITH OCaml-LGPL-linking-exception")
+
+(authors "Krivonosov Konstantin ")
+
+(maintainers "Krivonosov Konstantin ")
+
+(bug_reports "https://github.com/Kakadu/fp25")
+
+(homepage "https://github.com/Kakadu/fp25")
+
+(package
+ (name Krivonosov)
+ (synopsis "An interpreter for mimiML")
+ (description
+ "A Call-by-Value miniML interpreter featuring recursion, arithmetic, and monadic error handling")
+ (documentation "https://kakadu.github.io/fp25/docs/Krivonosov")
+ (version 0.1)
+ (depends
+ (dune
+ (= "3.19.1"))
+ (angstrom
+ (= "0.16.0"))
+ base
+ stdio
+ (ppx_inline_test :with-test)
+ ppx_expect
+ ppx_deriving
+ bisect_ppx
+ (qcheck :with-test)
+ (qcheck-core :with-test)
+ (odoc :with-doc)
+ (ocamlformat
+ (and
+ :build
+ (= "0.26.2")))
+ ; base
+ ; After adding dependencies to 'dune' files add the same dependecies here too
+ ))
diff --git a/Krivonosov/lib/ast.mli b/Krivonosov/lib/ast.mli
new file mode 100644
index 00000000..606d38e9
--- /dev/null
+++ b/Krivonosov/lib/ast.mli
@@ -0,0 +1,34 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+type name = string
+
+(** Binary operators *)
+type binop =
+ | Add (** [+] *)
+ | Sub (** [-] *)
+ | Mul (** [*] *)
+ | Div (** [/] *)
+ | Mod (** [%] *)
+ | Eq (** [=] *)
+ | Neq (** [<>] *)
+ | Lt (** [<] *)
+ | Gt (** [>] *)
+ | Leq (** [<=] *)
+ | Geq (** [>=] *)
+
+(** The main type for our AST *)
+type 'name t =
+ | Var of 'name (** Variable [x] *)
+ | Abs of 'name * 'name t (** Abstraction [λx.t] *)
+ | App of 'name t * 'name t (** Application [f g ] *)
+ | Int of int (** Integer literal [42] *)
+ | BinOp of binop * 'name t * 'name t (** Binary operation [e1 + e2] *)
+ | If of 'name t * 'name t * 'name t option (** Conditional [if cond then e1 else e2] *)
+ | Let of bool * 'name * 'name t * 'name t
+ (** Let binding [let (rec) x = e1 in e2]. bool indicates recursion *)
diff --git a/Krivonosov/lib/dune b/Krivonosov/lib/dune
new file mode 100644
index 00000000..c8dc6c2f
--- /dev/null
+++ b/Krivonosov/lib/dune
@@ -0,0 +1,10 @@
+(library
+ (name lambda_lib)
+ (public_name Krivonosov.Lib)
+ (modules Ast Interpret Parser Print)
+ (modules_without_implementation ast)
+ (libraries base stdio angstrom)
+ (preprocess
+ (pps ppx_deriving.show))
+ (instrumentation
+ (backend bisect_ppx)))
diff --git a/Krivonosov/lib/interpret.ml b/Krivonosov/lib/interpret.ml
new file mode 100644
index 00000000..7fe3743c
--- /dev/null
+++ b/Krivonosov/lib/interpret.ml
@@ -0,0 +1,146 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Base
+open Base.Result.Monad_infix
+
+type error =
+ | UnknownVariable of string
+ | DivisionByZero
+ | TypeMismatch
+ | StepLimitExceeded
+
+(** Values in our interpreter *)
+type value =
+ | VInt of int
+ | VClosure of string * string Ast.t * environment
+ | VBuiltin of string * (value -> (value, error) Result.t)
+ | VUnit
+
+and environment = (string * value) list
+
+(** Lookup variable in environment *)
+let lookup env name =
+ match List.Assoc.find ~equal:String.equal env name with
+ | Some v -> Ok v
+ | None -> Error (UnknownVariable name)
+;;
+
+(** Evaluate binary operation *)
+let eval_binop op v1 v2 =
+ match op, v1, v2 with
+ | Ast.Add, VInt a, VInt b -> Ok (VInt (a + b))
+ | Ast.Sub, VInt a, VInt b -> Ok (VInt (a - b))
+ | Ast.Mul, VInt a, VInt b -> Ok (VInt (a * b))
+ | Ast.Div, VInt _, VInt 0 -> Error DivisionByZero
+ | Ast.Div, VInt a, VInt b -> Ok (VInt (a / b))
+ | Ast.Mod, VInt _, VInt 0 -> Error DivisionByZero
+ | Ast.Mod, VInt a, VInt b -> Ok (VInt (a % b))
+ | Ast.Eq, VInt a, VInt b -> Ok (VInt (if a = b then 1 else 0))
+ | Ast.Neq, VInt a, VInt b -> Ok (VInt (if a <> b then 1 else 0))
+ | Ast.Lt, VInt a, VInt b -> Ok (VInt (if a < b then 1 else 0))
+ | Ast.Gt, VInt a, VInt b -> Ok (VInt (if a > b then 1 else 0))
+ | Ast.Leq, VInt a, VInt b -> Ok (VInt (if a <= b then 1 else 0))
+ | Ast.Geq, VInt a, VInt b -> Ok (VInt (if a >= b then 1 else 0))
+ | _ -> Error TypeMismatch
+;;
+
+(** Main evaluation function with step counter *)
+let rec eval steps_remaining env expr =
+ if steps_remaining <= 0
+ then Error StepLimitExceeded
+ else (
+ let steps = steps_remaining - 1 in
+ match expr with
+ | Ast.Int n -> Ok (VInt n)
+ | Ast.Var name -> lookup env name
+ | Ast.Abs (param, body) -> Ok (VClosure (param, body, env))
+ | Ast.BinOp (op, l, r) ->
+ eval steps env l >>= fun vl -> eval steps env r >>= fun vr -> eval_binop op vl vr
+ | Ast.If (cond, then_branch, else_branch_opt) ->
+ eval steps env cond
+ >>= (function
+ | VInt 0 ->
+ (match else_branch_opt with
+ | Some else_branch -> eval steps env else_branch
+ | None -> Ok (VInt 0))
+ | VInt _ -> eval steps env then_branch
+ | _ -> Error TypeMismatch)
+ | Ast.Let (is_rec, name, binding, body) ->
+ if is_rec
+ then (
+ match binding with
+ | Ast.Abs (param, func_body) ->
+ (* Recursive environment: function references itself *)
+ let rec new_env = (name, VClosure (param, func_body, new_env)) :: env in
+ eval steps new_env body
+ | _ ->
+ eval steps env binding
+ >>= fun value ->
+ let new_env = (name, value) :: env in
+ eval steps new_env body)
+ else
+ eval steps env binding
+ >>= fun value ->
+ let new_env = (name, value) :: env in
+ eval steps new_env body
+ | Ast.App (f, arg) ->
+ eval steps env f
+ >>= (function
+ | VClosure (param, body, closure_env) ->
+ eval steps env arg
+ >>= fun varg ->
+ let new_env = (param, varg) :: closure_env in
+ eval steps new_env body
+ | VBuiltin (_, builtin_fn) -> eval steps env arg >>= builtin_fn
+ | _ -> Error TypeMismatch))
+;;
+
+(** Create initial environment with built-in functions *)
+let initial_env () =
+ let print_builtin =
+ VBuiltin
+ ( "print"
+ , fun v ->
+ (match v with
+ | VInt n -> Stdio.printf "%d\n%!" n
+ | VClosure _ -> Stdio.printf "\n%!"
+ | VBuiltin (name, _) -> Stdio.printf "\n%!" name
+ | VUnit -> Stdio.printf "()\n%!");
+ Ok VUnit )
+ in
+ let rec fix_apply f =
+ VBuiltin
+ ( "fix_partial"
+ , fun x ->
+ match f with
+ | VClosure _ | VBuiltin _ ->
+ let fix_f = fix_apply f in
+ apply f fix_f >>= fun partial -> apply partial x
+ | _ -> Error TypeMismatch )
+ and apply fn arg =
+ match fn with
+ | VClosure (param, body, closure_env) ->
+ let new_env = (param, arg) :: closure_env in
+ eval 10000 new_env body
+ | VBuiltin (_, builtin_fn) -> builtin_fn arg
+ | _ -> Error TypeMismatch
+ in
+ let fix_builtin =
+ VBuiltin
+ ( "fix"
+ , fun f ->
+ match f with
+ | VClosure _ | VBuiltin _ -> Ok (fix_apply f)
+ | _ -> Error TypeMismatch )
+ in
+ [ "print", print_builtin; "fix", fix_builtin ]
+;;
+
+(** Public function to evaluate an AST expression *)
+let eval_expr ?(max_steps = 10000) ast = eval max_steps (initial_env ()) ast
diff --git a/Krivonosov/lib/interpret.mli b/Krivonosov/lib/interpret.mli
new file mode 100644
index 00000000..09bf81ff
--- /dev/null
+++ b/Krivonosov/lib/interpret.mli
@@ -0,0 +1,26 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+(** Error types for interpreter *)
+type error =
+ | UnknownVariable of string
+ | DivisionByZero
+ | TypeMismatch
+ | StepLimitExceeded
+
+(** Values in our interpreter *)
+type value =
+ | VInt of int
+ | VClosure of string * string Ast.t * environment
+ | VBuiltin of string * (value -> (value, error) Base.Result.t)
+ | VUnit
+
+and environment = (string * value) list
+
+(** Evaluate an AST expression with optional step limit *)
+val eval_expr : ?max_steps:int -> string Ast.t -> (value, error) Base.Result.t
diff --git a/Krivonosov/lib/parser.ml b/Krivonosov/lib/parser.ml
new file mode 100644
index 00000000..32d2e9ee
--- /dev/null
+++ b/Krivonosov/lib/parser.ml
@@ -0,0 +1,174 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Angstrom
+
+let is_space = function
+ | ' ' | '\t' | '\n' | '\r' -> true
+ | _ -> false
+;;
+
+let spaces = skip_while is_space
+
+(* Keyword filtering *)
+let is_keyword = function
+ | "let" | "rec" | "if" | "then" | "else" | "in" | "fun" -> true
+ | _ -> false
+;;
+
+let is_ident_char = function
+ | 'a' .. 'z' | 'A' .. 'Z' | '0' .. '9' | '_' | '\'' -> true
+ | _ -> false
+;;
+
+(* Word boundary — next char must not be part of an identifier *)
+let word_boundary =
+ peek_char
+ >>= function
+ | Some c when is_ident_char c -> fail "expected word boundary"
+ | _ -> return ()
+;;
+
+(* Keyword parser: matches exact word and skips trailing spaces *)
+let keyword w = string w *> word_boundary *> spaces
+
+(* Multi-character identifier parser *)
+let identifier =
+ let first_char_parser =
+ satisfy (function
+ | 'a' .. 'z' | '_' -> true
+ | _ -> false)
+ in
+ lift2
+ (fun fc rest -> String.make 1 fc ^ rest)
+ first_char_parser
+ (take_while is_ident_char)
+ >>= fun ident ->
+ if is_keyword ident
+ then fail ("Keyword '" ^ ident ^ "' cannot be used as identifier")
+ else return ident
+;;
+
+type error = Parsing_error of string
+
+let pp_error ppf = function
+ | Parsing_error s -> Format.fprintf ppf "%s" s
+;;
+
+(* Integer literal parser *)
+let pinteger =
+ take_while1 (function
+ | '0' .. '9' -> true
+ | _ -> false)
+ >>| int_of_string
+ >>| fun n -> Ast.Int n
+;;
+
+(* Chainl1: left-associative infix operator parser *)
+let chainl1 p op =
+ let rec go acc = op >>= (fun f -> p >>= fun x -> go (f acc x)) <|> return acc in
+ p >>= go
+;;
+
+(* Main parser using single fix point *)
+let pexpr =
+ fix (fun pexpr ->
+ (* Atomic expressions: integers, variables and parenthesized expressions *)
+ let patom =
+ spaces
+ *> choice
+ [ char '(' *> pexpr <* char ')' <* spaces "Parentheses expected"
+ ; pinteger <* spaces
+ ; (identifier <* spaces >>| fun name -> Ast.Var name)
+ ]
+ in
+ (* Lambda abstractions: fun x y z -> body *)
+ let plambda =
+ keyword "fun" *> many1 (identifier <* spaces)
+ <* string "->"
+ <* spaces
+ >>= fun params ->
+ pexpr
+ >>| fun body ->
+ (* Desugar: fun x y z -> body becomes fun x -> fun y -> fun z -> body *)
+ List.fold_right (fun param acc -> Ast.Abs (param, acc)) params body
+ in
+ (* If-then-else expression *)
+ let pif =
+ keyword "if" *> pexpr
+ >>= fun cond ->
+ spaces *> keyword "then" *> pexpr
+ >>= fun then_branch ->
+ option None (spaces *> keyword "else" *> pexpr >>| Option.some)
+ >>| fun else_branch -> Ast.If (cond, then_branch, else_branch)
+ in
+ (* Let expression *)
+ let plet =
+ keyword "let" *> option false (keyword "rec" *> return true)
+ >>= fun is_rec ->
+ identifier
+ <* spaces
+ <* char '='
+ <* spaces
+ >>= fun name ->
+ pexpr
+ >>= fun binding ->
+ spaces *> keyword "in" *> pexpr >>| fun body -> Ast.Let (is_rec, name, binding, body)
+ in
+ (* Application: sequence of atoms *)
+ let papp =
+ patom
+ >>= fun first ->
+ many patom >>| fun rest -> List.fold_left (fun acc e -> Ast.App (acc, e)) first rest
+ in
+ (* Binary operators with precedence *)
+ (* Comparison operators: =, <>, <, >, <=, >= (lowest precedence) *)
+ let pcmp_op =
+ spaces
+ *> choice
+ [ string "<=" *> return (fun l r -> Ast.BinOp (Ast.Leq, l, r))
+ ; string ">=" *> return (fun l r -> Ast.BinOp (Ast.Geq, l, r))
+ ; string "<>" *> return (fun l r -> Ast.BinOp (Ast.Neq, l, r))
+ ; char '<' *> return (fun l r -> Ast.BinOp (Ast.Lt, l, r))
+ ; char '>' *> return (fun l r -> Ast.BinOp (Ast.Gt, l, r))
+ ; char '=' *> return (fun l r -> Ast.BinOp (Ast.Eq, l, r))
+ ]
+ <* spaces
+ in
+ (* Additive operators: +, - *)
+ let padd_op =
+ spaces
+ *> choice
+ [ char '+' *> return (fun l r -> Ast.BinOp (Ast.Add, l, r))
+ ; char '-' *> return (fun l r -> Ast.BinOp (Ast.Sub, l, r))
+ ]
+ <* spaces
+ in
+ (* Multiplicative operators: *, /, % (higher precedence) *)
+ let pmul_op =
+ spaces
+ *> choice
+ [ char '*' *> return (fun l r -> Ast.BinOp (Ast.Mul, l, r))
+ ; char '/' *> return (fun l r -> Ast.BinOp (Ast.Div, l, r))
+ ; char '%' *> return (fun l r -> Ast.BinOp (Ast.Mod, l, r))
+ ]
+ <* spaces
+ in
+ (* Precedence levels: mul > add > cmp > app > lambda *)
+ let pmul = chainl1 papp pmul_op in
+ let padd = chainl1 pmul padd_op in
+ let pcmp = chainl1 padd pcmp_op in
+ (* Top level: try let, if, lambda first, then comparison *)
+ spaces *> choice [ plet; pif; plambda; pcmp ] <* spaces)
+;;
+
+let parse str =
+ match Angstrom.parse_string ~consume:Angstrom.Consume.All pexpr str with
+ | Result.Ok x -> Result.Ok x
+ | Error er -> Result.Error (Parsing_error er)
+;;
diff --git a/Krivonosov/lib/parser.mli b/Krivonosov/lib/parser.mli
new file mode 100644
index 00000000..52f3a2a1
--- /dev/null
+++ b/Krivonosov/lib/parser.mli
@@ -0,0 +1,14 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+type error = Parsing_error of string
+
+val pp_error : Format.formatter -> error -> unit
+
+(** Main entry of parser *)
+val parse : string -> (Ast.name Ast.t, error) result
diff --git a/Krivonosov/lib/print.ml b/Krivonosov/lib/print.ml
new file mode 100644
index 00000000..e98be96f
--- /dev/null
+++ b/Krivonosov/lib/print.ml
@@ -0,0 +1,77 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Ast
+
+(** Structural printing for debugging *)
+let rec print_ast = function
+ | Int n -> Printf.sprintf "Int %d" n
+ | Var x -> Printf.sprintf "Var %S" x
+ | BinOp (op, l, r) ->
+ let op_str =
+ match op with
+ | Add -> "Add"
+ | Sub -> "Sub"
+ | Mul -> "Mul"
+ | Div -> "Div"
+ | Mod -> "Mod"
+ | Eq -> "Eq"
+ | Neq -> "Neq"
+ | Lt -> "Lt"
+ | Gt -> "Gt"
+ | Leq -> "Leq"
+ | Geq -> "Geq"
+ in
+ Printf.sprintf "BinOp (%s, %s, %s)" op_str (print_ast l) (print_ast r)
+ | If (c, t, None) -> Printf.sprintf "If (%s, %s, None)" (print_ast c) (print_ast t)
+ | If (c, t, Some e) ->
+ Printf.sprintf "If (%s, %s, Some %s)" (print_ast c) (print_ast t) (print_ast e)
+ | Let (is_rec, x, e, b) ->
+ Printf.sprintf
+ "Let (%s, %S, %s, %s)"
+ (if is_rec then "true" else "false")
+ x
+ (print_ast e)
+ (print_ast b)
+ | Abs (param, body) -> Printf.sprintf "Abs (%S, %s)" param (print_ast body)
+ | App (f, a) -> Printf.sprintf "App (%s, %s)" (print_ast f) (print_ast a)
+;;
+
+(** Human-readable printing *)
+let rec print_expr = function
+ | Int n -> string_of_int n
+ | Var s -> s
+ | BinOp (op, l, r) ->
+ let op_str =
+ match op with
+ | Add -> "+"
+ | Sub -> "-"
+ | Mul -> "*"
+ | Div -> "/"
+ | Mod -> "%"
+ | Eq -> "="
+ | Neq -> "<>"
+ | Lt -> "<"
+ | Gt -> ">"
+ | Leq -> "<="
+ | Geq -> ">="
+ in
+ Printf.sprintf "(%s %s %s)" (print_expr l) op_str (print_expr r)
+ | If (c, t, None) -> Printf.sprintf "(if %s then %s)" (print_expr c) (print_expr t)
+ | If (c, t, Some e) ->
+ Printf.sprintf "(if %s then %s else %s)" (print_expr c) (print_expr t) (print_expr e)
+ | Let (is_rec, name, value, body) ->
+ Printf.sprintf
+ "(let %s%s = %s in %s)"
+ (if is_rec then "rec " else "")
+ name
+ (print_expr value)
+ (print_expr body)
+ | Abs (param, body) -> Printf.sprintf "(fun %s -> %s)" param (print_expr body)
+ | App (f, a) -> Printf.sprintf "(%s %s)" (print_expr f) (print_expr a)
+;;
diff --git a/Krivonosov/lib/print.mli b/Krivonosov/lib/print.mli
new file mode 100644
index 00000000..9ff93b1a
--- /dev/null
+++ b/Krivonosov/lib/print.mli
@@ -0,0 +1,15 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+(** Print AST in structural form for debugging
+ Example: [Int 42], [Var "x"], [BinOp (Add, Int 1, Int 2)] *)
+val print_ast : string Ast.t -> string
+
+(** Print AST in human-readable form
+ Example: [42], [x], [(1 + 2)] *)
+val print_expr : string Ast.t -> string
diff --git a/Krivonosov/tests/.gitignore b/Krivonosov/tests/.gitignore
new file mode 100644
index 00000000..26685e79
--- /dev/null
+++ b/Krivonosov/tests/.gitignore
@@ -0,0 +1 @@
+lam*.txt
\ No newline at end of file
diff --git a/Krivonosov/tests/dune b/Krivonosov/tests/dune
new file mode 100644
index 00000000..e50bc26f
--- /dev/null
+++ b/Krivonosov/tests/dune
@@ -0,0 +1,12 @@
+(cram
+ (applies_to interpret_tests)
+ (deps ../bin/REPL.exe))
+
+(library
+ (name tests)
+ (modules tests)
+ (libraries lambda_lib qcheck)
+ (preprocess
+ (pps ppx_expect ppx_deriving.show))
+ (instrumentation
+ (backend bisect_ppx)))
diff --git a/Krivonosov/tests/interpret_tests.t b/Krivonosov/tests/interpret_tests.t
new file mode 100644
index 00000000..f47cfa8e
--- /dev/null
+++ b/Krivonosov/tests/interpret_tests.t
@@ -0,0 +1,349 @@
+Copyright 2021-2026, Kakadu and contributors
+SPDX-License-Identifier: CC0-1.0
+
+Cram tests here. They run and compare program output to the expected output
+https://dune.readthedocs.io/en/stable/tests.html#cram-tests
+Use `dune promote` after you change things that should runned
+
+miniML Interpreter tests
+========================
+
+Basic arithmetic
+ $ ../bin/REPL.exe < 2 + 3
+ 5
+ $ ../bin/REPL.exe < 10 - 4
+ 6
+ $ ../bin/REPL.exe < 3 * 4
+ 12
+ $ ../bin/REPL.exe < 15 / 3
+ 5
+ $ ../bin/REPL.exe < 17 % 5
+ 2
+
+Comparison operators
+ $ ../bin/REPL.exe < 5 = 5
+ 1
+ $ ../bin/REPL.exe < 5 = 3
+ 0
+ $ ../bin/REPL.exe < 5 <> 3
+ 1
+ $ ../bin/REPL.exe < 5 <> 5
+ 0
+ $ ../bin/REPL.exe < 3 < 5
+ 1
+ $ ../bin/REPL.exe < 5 < 3
+ 0
+ $ ../bin/REPL.exe < 5 > 3
+ 1
+ $ ../bin/REPL.exe < 3 > 5
+ 0
+ $ ../bin/REPL.exe < 5 <= 5
+ 1
+ $ ../bin/REPL.exe < 6 <= 5
+ 0
+ $ ../bin/REPL.exe < 5 >= 5
+ 1
+ $ ../bin/REPL.exe < 4 >= 5
+ 0
+
+Conditional expressions
+ $ ../bin/REPL.exe < if 1 then 100 else 200
+ 100
+ $ ../bin/REPL.exe < if 0 then 100 else 200
+ 200
+ $ ../bin/REPL.exe < if (3 > 2) then 42 else 0
+ 42
+ $ ../bin/REPL.exe < if 1 then 42
+ 42
+ $ ../bin/REPL.exe < if 0 then 42
+ 0
+
+Let bindings
+ $ ../bin/REPL.exe < let x = 10 in x + 5
+ 15
+ $ ../bin/REPL.exe < let x = 5 in let y = 10 in x * y
+ 50
+ $ ../bin/REPL.exe < let rec x = 42 in x
+ 42
+
+Factorial with let rec
+ $ ../bin/REPL.exe < let rec fact = fun n -> if n <= 1 then 1 else n * fact (n - 1) in fact 0
+ 1
+ $ ../bin/REPL.exe < let rec fact = fun n -> if n <= 1 then 1 else n * fact (n - 1) in fact 1
+ 1
+ $ ../bin/REPL.exe < let rec fact = fun n -> if n <= 1 then 1 else n * fact (n - 1) in fact 5
+ 120
+ $ ../bin/REPL.exe < let rec fact = fun n -> if n <= 1 then 1 else n * fact (n - 1) in fact 10
+ 3628800
+
+Fibonacci with let rec
+ $ ../bin/REPL.exe < let rec fib = fun n -> if n <= 1 then n else fib (n - 1) + fib (n - 2) in fib 0
+ 0
+ $ ../bin/REPL.exe < let rec fib = fun n -> if n <= 1 then n else fib (n - 1) + fib (n - 2) in fib 1
+ 1
+ $ ../bin/REPL.exe < let rec fib = fun n -> if n <= 1 then n else fib (n - 1) + fib (n - 2) in fib 7
+ 13
+ $ ../bin/REPL.exe < let rec fib = fun n -> if n <= 1 then n else fib (n - 1) + fib (n - 2) in fib 10
+ 55
+
+Fix combinator (Z-combinator) — recursion without let rec on the function itself
+ $ ../bin/REPL.exe < let rec fix = fun f x -> f (fix f) x in let fac1 = fun self n -> if n <= 1 then 1 else n * self (n - 1) in fix fac1 5
+ 120
+ $ ../bin/REPL.exe < let rec fix = fun f x -> f (fix f) x in let fib1 = fun self n -> if n <= 1 then n else self (n - 1) + self (n - 2) in fix fib1 10
+ 55
+
+Builtin fix combinator — recursion without let rec at all
+ $ ../bin/REPL.exe < let fac = fun self n -> if n <= 1 then 1 else n * self (n - 1) in fix fac 5
+ 120
+ $ ../bin/REPL.exe < let fib = fun self n -> if n <= 1 then n else self (n - 1) + self (n - 2) in fix fib 10
+ 55
+ $ ../bin/REPL.exe < fix
+
+ $ ../bin/REPL.exe < fix 42
+ Type error
+ [1]
+
+Multi-parameter syntax sugar
+ $ ../bin/REPL.exe < (fun x y -> x + y) 2 3
+ 5
+ $ ../bin/REPL.exe < (fun x y z -> x + y + z) 1 2 3
+ 6
+
+Print function
+ $ ../bin/REPL.exe < print 42
+ 42
+ ()
+ $ ../bin/REPL.exe < print (5 + 3)
+ 8
+ ()
+ $ ../bin/REPL.exe < let x = print 10 in print 20
+ 10
+ 20
+ ()
+ $ ../bin/REPL.exe < print (fun x -> x)
+
+ ()
+ $ ../bin/REPL.exe < print print
+
+ ()
+ $ ../bin/REPL.exe < print (print 42)
+ 42
+ ()
+ ()
+
+Returning closures and builtins
+ $ ../bin/REPL.exe < fun x -> x
+
+ $ ../bin/REPL.exe < print
+
+
+Error handling - Division by zero
+ $ ../bin/REPL.exe < 10 / 0
+ Division by zero
+ [1]
+
+Error handling - Modulo by zero
+ $ ../bin/REPL.exe < 10 % 0
+ Division by zero
+ [1]
+
+Error handling - Unknown variable
+ $ ../bin/REPL.exe < x + 5
+ Unbound variable: x
+ [1]
+
+Error handling - Type mismatch
+ $ ../bin/REPL.exe < (fun x -> x) + 5
+ Type error
+ [1]
+ $ ../bin/REPL.exe < 5 + (fun x -> x)
+ Type error
+ [1]
+ $ ../bin/REPL.exe < 42 10
+ Type error
+ [1]
+ $ ../bin/REPL.exe < if (fun x -> x) then 1 else 0
+ Type error
+ [1]
+
+Step limit - Infinite loop with let rec
+ $ ../bin/REPL.exe -max-steps 100 < let rec loop = fun x -> loop x in loop 0
+ Step limit exceeded
+ [1]
+
+Step limit - Factorial completes within limit
+ $ ../bin/REPL.exe -max-steps 200 < let rec fact = fun n -> if n <= 1 then 1 else n * fact (n - 1) in fact 5
+ 120
+
+REPL argument parsing edge cases
+=================================
+
+Invalid -max-steps value (non-numeric)
+ $ ../bin/REPL.exe -max-steps invalid < 42
+ Error: Invalid value for -max-steps: invalid
+ [1]
+
+Unknown argument
+ $ ../bin/REPL.exe -unknown-arg < 42
+ Error: Unknown argument: -unknown-arg
+ [1]
+
+
+Syntax error - unmatched parenthesis
+ $ ../bin/REPL.exe < (5 + 3
+ Error: : no more choices
+ [1]
+
+Syntax error - missing closing paren with complex expr
+ $ ../bin/REPL.exe < (fun x -> x + 1
+ Error: : no more choices
+ [1]
+
+Operator precedence
+ $ ../bin/REPL.exe < 1 + 2 * 3
+ 7
+ $ ../bin/REPL.exe < (1 + 2) * 3
+ 9
+
+If with non-zero condition (not just 1)
+ $ ../bin/REPL.exe < if 42 then 1 else 0
+ 1
+ $ ../bin/REPL.exe < if 5 + 3 then 1 else 0
+ 1
+
+Closure captures outer variable
+ $ ../bin/REPL.exe < let x = 5 in (fun y -> x + y) 3
+ 8
+ $ ../bin/REPL.exe < let x = 10 in let f = fun y -> x + y in f 5
+ 15
+
+Variable shadowing
+ $ ../bin/REPL.exe < let x = 5 in let x = 10 in x
+ 10
+ $ ../bin/REPL.exe < let x = 5 in let x = 10 in x + x
+ 20
+
+Partial application
+ $ ../bin/REPL.exe < let f = (fun x y -> x + y) 2 in f 3
+ 5
+ $ ../bin/REPL.exe < let f = (fun x y z -> x + y + z) 1 2 in f 3
+ 6
+
+Type error - applying number as function
+ $ ../bin/REPL.exe < let f = 5 in f 3
+ Type error
+ [1]
+
+Fused keywords must be rejected
+ $ ../bin/REPL.exe < letrec f = fun x -> x in f 1
+ Error: : end_of_input
+ [1]
+ $ ../bin/REPL.exe < letx = 5 in x
+ Error: : end_of_input
+ [1]
+ $ ../bin/REPL.exe < ifthen 42
+ Unbound variable: ifthen
+ [1]
+ $ ../bin/REPL.exe < funx -> x
+ Error: : end_of_input
+ [1]
+ $ ../bin/REPL.exe < if 1 then42 else 0
+ Error: : no more choices
+ [1]
+ $ ../bin/REPL.exe < if 1 then 42 else0
+ Type error
+ [1]
+ $ ../bin/REPL.exe < let x = 5 inx
+ Error: : no more choices
+ [1]
+
+Keywords without space before parens/digits (word boundary, not whitespace)
+ $ ../bin/REPL.exe < let x = 5 in(x)
+ 5
+ $ ../bin/REPL.exe < if 1 then(42) else 0
+ 42
+ $ ../bin/REPL.exe < let x = 5 in(x + 1)
+ 6
diff --git a/Krivonosov/tests/tests.ml b/Krivonosov/tests/tests.ml
new file mode 100644
index 00000000..ac28d384
--- /dev/null
+++ b/Krivonosov/tests/tests.ml
@@ -0,0 +1,322 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+(** ***** UNIT TESTS COULD GO HERE (JUST AN EXAMPLE) *)
+let rec fact n = if n = 1 then 1 else n * fact (n - 1)
+
+let%test _ = fact 5 = 120
+
+(* These is a simple unit test that tests a single function 'fact'
+ If you want to test something large, like interpretation of a piece
+ of a minilanguge, it is not longer a unit tests but an integration test.
+ Read about dune's cram tests and put the test into `demos/somefile.t`.
+*)
+
+open Lambda_lib
+open Lambda_lib.Interpret
+open QCheck
+
+let parse_optimistically str = Result.get_ok (Parser.parse str)
+let pp = Lambda_lib.Print.print_ast
+
+let%expect_test "parse simple application" =
+ Format.printf "%s" (pp (parse_optimistically "x y"));
+ [%expect {| App (Var "x", Var "y") |}]
+;;
+
+let%expect_test "parse application with parens" =
+ Format.printf "%s" (pp (parse_optimistically "(x y)"));
+ [%expect {| App (Var "x", Var "y") |}]
+;;
+
+(* Test all binary operators *)
+let%expect_test "parse division" =
+ Format.printf "%s" (pp (parse_optimistically "10 / 2"));
+ [%expect {| BinOp (Div, Int 10, Int 2) |}]
+;;
+
+let%expect_test "parse modulo" =
+ Format.printf "%s" (pp (parse_optimistically "10 % 3"));
+ [%expect {| BinOp (Mod, Int 10, Int 3) |}]
+;;
+
+let%expect_test "parse equality" =
+ Format.printf "%s" (pp (parse_optimistically "5 = 5"));
+ [%expect {| BinOp (Eq, Int 5, Int 5) |}]
+;;
+
+let%expect_test "parse not equal" =
+ Format.printf "%s" (pp (parse_optimistically "5 <> 3"));
+ [%expect {| BinOp (Neq, Int 5, Int 3) |}]
+;;
+
+let%expect_test "parse less than" =
+ Format.printf "%s" (pp (parse_optimistically "3 < 5"));
+ [%expect {| BinOp (Lt, Int 3, Int 5) |}]
+;;
+
+let%expect_test "parse greater than" =
+ Format.printf "%s" (pp (parse_optimistically "5 > 3"));
+ [%expect {| BinOp (Gt, Int 5, Int 3) |}]
+;;
+
+let%expect_test "parse less or equal" =
+ Format.printf "%s" (pp (parse_optimistically "3 <= 5"));
+ [%expect {| BinOp (Leq, Int 3, Int 5) |}]
+;;
+
+let%expect_test "parse greater or equal" =
+ Format.printf "%s" (pp (parse_optimistically "5 >= 3"));
+ [%expect {| BinOp (Geq, Int 5, Int 3) |}]
+;;
+
+let%expect_test "parse if without else" =
+ Format.printf "%s" (pp (parse_optimistically "if 1 then 42"));
+ [%expect {| If (Int 1, Int 42, None) |}]
+;;
+
+let%expect_test "parse if with else" =
+ Format.printf "%s" (pp (parse_optimistically "if 1 then 42 else 0"));
+ [%expect {| If (Int 1, Int 42, Some Int 0) |}]
+;;
+
+let%expect_test "parse let without rec" =
+ Format.printf "%s" (pp (parse_optimistically "let x = 5 in x"));
+ [%expect {| Let (false, "x", Int 5, Var "x") |}]
+;;
+
+let%expect_test "parse let rec" =
+ Format.printf "%s" (pp (parse_optimistically "let rec f = fun x -> x in f"));
+ [%expect {| Let (true, "f", Abs ("x", Var "x"), Var "f") |}]
+;;
+
+(* ========================================================================== *)
+(* ADDITIONAL COVERAGE TESTS *)
+(* ========================================================================== *)
+
+let%expect_test "parse multi-param fun syntax" =
+ Format.printf "%s" (pp (parse_optimistically "fun x y -> x"));
+ [%expect {| Abs ("x", Abs ("y", Var "x")) |}]
+;;
+
+(* Interpreter: Recursive binding tests *)
+let%expect_test "eval recursive function - factorial" =
+ let ast =
+ parse_optimistically
+ "let rec fact = fun n -> if n <= 1 then 1 else n * fact (n - 1) in fact 5"
+ in
+ (match eval_expr ast with
+ | Result.Ok (VInt n) -> Format.printf "%d" n
+ | Result.Ok (VClosure _) -> Format.printf ""
+ | Result.Ok _ -> Format.printf ""
+ | Result.Error (UnknownVariable s) -> Format.printf "UnknownVariable: %s" s
+ | Result.Error DivisionByZero -> Format.printf "DivisionByZero"
+ | Result.Error TypeMismatch -> Format.printf "TypeMismatch"
+ | Result.Error StepLimitExceeded -> Format.printf "StepLimitExceeded");
+ [%expect {| 120 |}]
+;;
+
+let%expect_test "eval if-then-else with 0 condition (false)" =
+ let ast = parse_optimistically "if 0 then 42 else 99" in
+ (match eval_expr ast with
+ | Result.Ok (VInt n) -> Format.printf "%d" n
+ | Result.Ok (VClosure _) -> Format.printf ""
+ | Result.Ok _ -> Format.printf ""
+ | Result.Error _ -> Format.printf "");
+ [%expect {| 99 |}]
+;;
+
+let%expect_test "eval if-then without else (non-zero)" =
+ let ast = parse_optimistically "if 1 then 42" in
+ (match eval_expr ast with
+ | Result.Ok (VInt n) -> Format.printf "%d" n
+ | Result.Ok (VClosure _) -> Format.printf ""
+ | Result.Ok _ -> Format.printf ""
+ | Result.Error _ -> Format.printf "");
+ [%expect {| 42 |}]
+;;
+
+let%expect_test "eval if-then without else (zero - no else)" =
+ let ast = parse_optimistically "if 0 then 42" in
+ (match eval_expr ast with
+ | Result.Ok (VInt n) -> Format.printf "%d" n
+ | Result.Ok (VClosure _) -> Format.printf ""
+ | Result.Ok _ -> Format.printf ""
+ | Result.Error _ -> Format.printf "");
+ [%expect {| 0 |}]
+;;
+
+let%expect_test "eval unknown variable error" =
+ let ast = parse_optimistically "unknown_var" in
+ (match eval_expr ast with
+ | Result.Ok _ -> Format.printf ""
+ | Result.Error (UnknownVariable s) -> Format.printf "UnknownVariable: %s" s
+ | Result.Error _ -> Format.printf "");
+ [%expect {| UnknownVariable: unknown_var |}]
+;;
+
+let%expect_test "eval division by zero" =
+ let ast = parse_optimistically "10 / 0" in
+ (match eval_expr ast with
+ | Result.Ok (VInt n) -> Format.printf "%d" n
+ | Result.Ok (VClosure _) -> Format.printf ""
+ | Result.Ok (VBuiltin (name, _)) -> Format.printf "" name
+ | Result.Ok VUnit -> Format.printf "()"
+ | Result.Error DivisionByZero -> Format.printf "DivisionByZero"
+ | Result.Error _ -> Format.printf "");
+ [%expect {| DivisionByZero |}]
+;;
+
+let%expect_test "eval modulo by zero" =
+ let ast = parse_optimistically "10 % 0" in
+ (match eval_expr ast with
+ | Result.Ok (VInt n) -> Format.printf "%d" n
+ | Result.Ok (VClosure _) -> Format.printf ""
+ | Result.Ok (VBuiltin (name, _)) -> Format.printf "" name
+ | Result.Ok VUnit -> Format.printf "()"
+ | Result.Error DivisionByZero -> Format.printf "DivisionByZero"
+ | Result.Error _ -> Format.printf "");
+ [%expect {| DivisionByZero |}]
+;;
+
+(* ========================================================================== *)
+(* QuickCheck Generators and Property-Based Tests *)
+(* ========================================================================== *)
+
+(** Generator for variable names *)
+let gen_name =
+ Gen.(
+ oneof_list [ "x"; "y"; "z"; "f"; "g"; "h"; "n"; "m"; "a"; "b"; "foo"; "bar"; "baz" ])
+;;
+
+(** Generator for binary operators *)
+let gen_binop = Gen.oneof_list Ast.[ Add; Sub; Mul; Div; Mod; Eq; Neq; Lt; Gt; Leq; Geq ]
+
+(** Generator for AST expressions with bounded depth
+ @param max_depth Maximum depth of the generated AST tree *)
+let gen_ast max_depth =
+ let open Gen in
+ let rec gen_ast_sized depth =
+ if depth <= 0
+ then
+ (* At max depth, generate only leaf nodes *)
+ oneof
+ [ map (fun n -> Ast.Int n) (int_range 0 100)
+ ; map (fun name -> Ast.Var name) gen_name
+ ]
+ else
+ (* Generate all kinds of expressions *)
+ oneof_weighted
+ [ (* Leaf nodes - higher weight for simpler expressions *)
+ 3, map (fun n -> Ast.Int n) (int_range 0 100)
+ ; 3, map (fun name -> Ast.Var name) gen_name (* Binary operations *)
+ ; ( 2
+ , map3
+ (fun op l r -> Ast.BinOp (op, l, r))
+ gen_binop
+ (gen_ast_sized (depth - 1))
+ (gen_ast_sized (depth - 1)) )
+ (* Abstraction (lambda) *)
+ ; ( 2
+ , map2
+ (fun param body -> Ast.Abs (param, body))
+ gen_name
+ (gen_ast_sized (depth - 1)) )
+ (* Application *)
+ ; ( 2
+ , map2
+ (fun f arg -> Ast.App (f, arg))
+ (gen_ast_sized (depth - 1))
+ (gen_ast_sized (depth - 1)) )
+ (* If-then-else *)
+ ; ( 1
+ , map3
+ (fun c t e -> Ast.If (c, t, Some e))
+ (gen_ast_sized (depth - 1))
+ (gen_ast_sized (depth - 1))
+ (gen_ast_sized (depth - 1)) )
+ (* Let binding (non-recursive only to avoid complexity) *)
+ ; ( 1
+ , map3
+ (fun name binding body -> Ast.Let (false, name, binding, body))
+ gen_name
+ (gen_ast_sized (depth - 1))
+ (gen_ast_sized (depth - 1)) )
+ ]
+ in
+ gen_ast_sized max_depth
+;;
+
+(** QuickCheck test: parse and print are inverses (round-trip property)
+ Property: for any AST, parsing the printed representation should yield the same AST *)
+let test_roundtrip_property =
+ Test.make
+ ~name:"parse-print roundtrip"
+ ~count:1000
+ (make (gen_ast 3))
+ (fun ast ->
+ let printed = Lambda_lib.Print.print_expr ast in
+ match Parser.parse printed with
+ | Result.Ok reparsed -> ast = reparsed
+ | Result.Error _ ->
+ (* If parsing fails, this is also acceptable since our printer might produce
+ expressions that are syntactically valid but the parser doesn't handle *)
+ true)
+;;
+
+(** QuickCheck test: printer always produces parseable output
+ Property: for any AST, the printed representation should be parseable *)
+let test_printer_produces_parseable =
+ Test.make
+ ~name:"printer produces parseable output"
+ ~count:1000
+ (make (gen_ast 3))
+ (fun ast ->
+ let printed = Lambda_lib.Print.print_expr ast in
+ match Parser.parse printed with
+ | Result.Ok _ -> true
+ | Result.Error _ -> false)
+;;
+
+(** QuickCheck test: print is deterministic
+ Property: printing the same AST twice should produce the same string *)
+let test_printer_deterministic =
+ Test.make
+ ~name:"printer is deterministic"
+ ~count:1000
+ (make (gen_ast 3))
+ (fun ast ->
+ let printed1 = Lambda_lib.Print.print_expr ast in
+ let printed2 = Lambda_lib.Print.print_expr ast in
+ printed1 = printed2)
+;;
+
+(** QuickCheck test: parser is deterministic
+ Property: parsing the same string twice should produce the same result *)
+let test_parser_deterministic =
+ Test.make
+ ~name:"parser is deterministic"
+ ~count:1000
+ (make Gen.(string_small_of printable))
+ (fun str ->
+ let result1 = Parser.parse str in
+ let result2 = Parser.parse str in
+ result1 = result2)
+;;
+
+(* Run QuickCheck tests *)
+let () =
+ let open QCheck_base_runner in
+ run_tests
+ [ test_roundtrip_property
+ ; test_printer_produces_parseable
+ ; test_printer_deterministic
+ ; test_parser_deterministic
+ ]
+ |> Stdlib.exit
+;;
diff --git a/Krivonosov/tests/tests.mli b/Krivonosov/tests/tests.mli
new file mode 100644
index 00000000..17727c97
--- /dev/null
+++ b/Krivonosov/tests/tests.mli
@@ -0,0 +1,9 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and contributors *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+(* This file is intentionally empty *)