diff --git a/Yackovlev/.gitignore b/Yackovlev/.gitignore
new file mode 100644
index 00000000..7102a822
--- /dev/null
+++ b/Yackovlev/.gitignore
@@ -0,0 +1,6 @@
+_build
+_coverage
+/_esy
+/node_modules
+/esy.lock
+/.melange.eobjs
diff --git a/Yackovlev/.ocamlformat b/Yackovlev/.ocamlformat
new file mode 100644
index 00000000..97f97080
--- /dev/null
+++ b/Yackovlev/.ocamlformat
@@ -0,0 +1,2 @@
+profile=janestreet
+version=0.26.2
diff --git a/Yackovlev/.zanuda b/Yackovlev/.zanuda
new file mode 100644
index 00000000..0f09b19b
--- /dev/null
+++ b/Yackovlev/.zanuda
@@ -0,0 +1 @@
+forward mutability_check ignore REPL.ml
diff --git a/Yackovlev/COPYING b/Yackovlev/COPYING
new file mode 100644
index 00000000..f288702d
--- /dev/null
+++ b/Yackovlev/COPYING
@@ -0,0 +1,674 @@
+ GNU 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.
+
+ Preamble
+
+ The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+ The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works. By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users. We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors. You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+ To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights. Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received. You must make sure that they, too, receive
+or can get the source code. And you must show them these terms so they
+know their rights.
+
+ Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+ For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software. For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+ Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so. This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software. The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable. Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products. If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+ Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary. To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ TERMS AND CONDITIONS
+
+ 0. Definitions.
+
+ "This License" refers to version 3 of the GNU General Public License.
+
+ "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+ "The Program" refers to any copyrightable work licensed under this
+License. Each licensee is addressed as "you". "Licensees" and
+"recipients" may be individuals or organizations.
+
+ To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy. The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+ A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+ To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy. Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+ To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies. Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+ An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License. If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+ 1. Source Code.
+
+ The "source code" for a work means the preferred form of the work
+for making modifications to it. "Object code" means any non-source
+form of a work.
+
+ A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+ The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form. A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+ The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities. However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work. For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+ The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+ The Corresponding Source for a work in source code form is that
+same work.
+
+ 2. Basic Permissions.
+
+ All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met. This License explicitly affirms your unlimited
+permission to run the unmodified Program. The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work. This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+ You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force. You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright. Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+ Conveying under any other circumstances is permitted solely under
+the conditions stated below. Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+ 3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+ No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+ When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+ 4. Conveying Verbatim Copies.
+
+ You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+ You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+ 5. Conveying Modified Source Versions.
+
+ You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+ a) The work must carry prominent notices stating that you modified
+ it, and giving a relevant date.
+
+ b) The work must carry prominent notices stating that it is
+ released under this License and any conditions added under section
+ 7. This requirement modifies the requirement in section 4 to
+ "keep intact all notices".
+
+ c) You must license the entire work, as a whole, under this
+ License to anyone who comes into possession of a copy. This
+ License will therefore apply, along with any applicable section 7
+ additional terms, to the whole of the work, and all its parts,
+ regardless of how they are packaged. This License gives no
+ permission to license the work in any other way, but it does not
+ invalidate such permission if you have separately received it.
+
+ d) If the work has interactive user interfaces, each must display
+ Appropriate Legal Notices; however, if the Program has interactive
+ interfaces that do not display Appropriate Legal Notices, your
+ work need not make them do so.
+
+ A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit. Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+ 6. Conveying Non-Source Forms.
+
+ You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+ a) Convey the object code in, or embodied in, a physical product
+ (including a physical distribution medium), accompanied by the
+ Corresponding Source fixed on a durable physical medium
+ customarily used for software interchange.
+
+ b) Convey the object code in, or embodied in, a physical product
+ (including a physical distribution medium), accompanied by a
+ written offer, valid for at least three years and valid for as
+ long as you offer spare parts or customer support for that product
+ model, to give anyone who possesses the object code either (1) a
+ copy of the Corresponding Source for all the software in the
+ product that is covered by this License, on a durable physical
+ medium customarily used for software interchange, for a price no
+ more than your reasonable cost of physically performing this
+ conveying of source, or (2) access to copy the
+ Corresponding Source from a network server at no charge.
+
+ c) Convey individual copies of the object code with a copy of the
+ written offer to provide the Corresponding Source. This
+ alternative is allowed only occasionally and noncommercially, and
+ only if you received the object code with such an offer, in accord
+ with subsection 6b.
+
+ d) Convey the object code by offering access from a designated
+ place (gratis or for a charge), and offer equivalent access to the
+ Corresponding Source in the same way through the same place at no
+ further charge. You need not require recipients to copy the
+ Corresponding Source along with the object code. If the place to
+ copy the object code is a network server, the Corresponding Source
+ may be on a different server (operated by you or a third party)
+ that supports equivalent copying facilities, provided you maintain
+ clear directions next to the object code saying where to find the
+ Corresponding Source. Regardless of what server hosts the
+ Corresponding Source, you remain obligated to ensure that it is
+ available for as long as needed to satisfy these requirements.
+
+ e) Convey the object code using peer-to-peer transmission, provided
+ you inform other peers where the object code and Corresponding
+ Source of the work are being offered to the general public at no
+ charge under subsection 6d.
+
+ A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+ A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling. In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage. For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product. A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+ "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source. The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+ If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information. But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+ The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed. Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+ Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+ 7. Additional Terms.
+
+ "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law. If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+ When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it. (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.) You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+ Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+ a) Disclaiming warranty or limiting liability differently from the
+ terms of sections 15 and 16 of this License; or
+
+ b) Requiring preservation of specified reasonable legal notices or
+ author attributions in that material or in the Appropriate Legal
+ Notices displayed by works containing it; or
+
+ c) Prohibiting misrepresentation of the origin of that material, or
+ requiring that modified versions of such material be marked in
+ reasonable ways as different from the original version; or
+
+ d) Limiting the use for publicity purposes of names of licensors or
+ authors of the material; or
+
+ e) Declining to grant rights under trademark law for use of some
+ trade names, trademarks, or service marks; or
+
+ f) Requiring indemnification of licensors and authors of that
+ material by anyone who conveys the material (or modified versions of
+ it) with contractual assumptions of liability to the recipient, for
+ any liability that these contractual assumptions directly impose on
+ those licensors and authors.
+
+ All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10. If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term. If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+ If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+ Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+ 8. Termination.
+
+ You may not propagate or modify a covered work except as expressly
+provided under this License. Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+ However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+ Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+ Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License. If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+ 9. Acceptance Not Required for Having Copies.
+
+ You are not required to accept this License in order to receive or
+run a copy of the Program. Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance. However,
+nothing other than this License grants you permission to propagate or
+modify any covered work. These actions infringe copyright if you do
+not accept this License. Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+ 10. Automatic Licensing of Downstream Recipients.
+
+ Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License. You are not responsible
+for enforcing compliance by third parties with this License.
+
+ An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations. If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+ You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License. For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+ 11. Patents.
+
+ A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based. The
+work thus licensed is called the contributor's "contributor version".
+
+ A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version. For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+ Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+ In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement). To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+ If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients. "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+ If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+ A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License. You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+ Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+ 12. No Surrender of Others' Freedom.
+
+ If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all. For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+ 13. Use with the GNU Affero General Public License.
+
+ Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work. The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+ 14. Revised Versions of this License.
+
+ The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation. If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+ If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+ Later license versions may give you additional or different
+permissions. However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+ 15. Disclaimer of Warranty.
+
+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+ 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
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+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
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+
+ Copyright (C)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see .
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ Copyright (C)
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+.
diff --git a/Yackovlev/COPYING.CC0 b/Yackovlev/COPYING.CC0
new file mode 100644
index 00000000..0e259d42
--- /dev/null
+++ b/Yackovlev/COPYING.CC0
@@ -0,0 +1,121 @@
+Creative Commons Legal Code
+
+CC0 1.0 Universal
+
+ CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
+ LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
+ ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
+ INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
+ REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
+ PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
+ THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
+ HEREUNDER.
+
+Statement of Purpose
+
+The laws of most jurisdictions throughout the world automatically confer
+exclusive Copyright and Related Rights (defined below) upon the creator
+and subsequent owner(s) (each and all, an "owner") of an original work of
+authorship and/or a database (each, a "Work").
+
+Certain owners wish to permanently relinquish those rights to a Work for
+the purpose of contributing to a commons of creative, cultural and
+scientific works ("Commons") that the public can reliably and without fear
+of later claims of infringement build upon, modify, incorporate in other
+works, reuse and redistribute as freely as possible in any form whatsoever
+and for any purposes, including without limitation commercial purposes.
+These owners may contribute to the Commons to promote the ideal of a free
+culture and the further production of creative, cultural and scientific
+works, or to gain reputation or greater distribution for their Work in
+part through the use and efforts of others.
+
+For these and/or other purposes and motivations, and without any
+expectation of additional consideration or compensation, the person
+associating CC0 with a Work (the "Affirmer"), to the extent that he or she
+is an owner of Copyright and Related Rights in the Work, voluntarily
+elects to apply CC0 to the Work and publicly distribute the Work under its
+terms, with knowledge of his or her Copyright and Related Rights in the
+Work and the meaning and intended legal effect of CC0 on those rights.
+
+1. Copyright and Related Rights. A Work made available under CC0 may be
+protected by copyright and related or neighboring rights ("Copyright and
+Related Rights"). Copyright and Related Rights include, but are not
+limited to, the following:
+
+ i. the right to reproduce, adapt, distribute, perform, display,
+ communicate, and translate a Work;
+ ii. moral rights retained by the original author(s) and/or performer(s);
+iii. publicity and privacy rights pertaining to a person's image or
+ likeness depicted in a Work;
+ iv. rights protecting against unfair competition in regards to a Work,
+ subject to the limitations in paragraph 4(a), below;
+ v. rights protecting the extraction, dissemination, use and reuse of data
+ in a Work;
+ vi. database rights (such as those arising under Directive 96/9/EC of the
+ European Parliament and of the Council of 11 March 1996 on the legal
+ protection of databases, and under any national implementation
+ thereof, including any amended or successor version of such
+ directive); and
+vii. other similar, equivalent or corresponding rights throughout the
+ world based on applicable law or treaty, and any national
+ implementations thereof.
+
+2. Waiver. To the greatest extent permitted by, but not in contravention
+of, applicable law, Affirmer hereby overtly, fully, permanently,
+irrevocably and unconditionally waives, abandons, and surrenders all of
+Affirmer's Copyright and Related Rights and associated claims and causes
+of action, whether now known or unknown (including existing as well as
+future claims and causes of action), in the Work (i) in all territories
+worldwide, (ii) for the maximum duration provided by applicable law or
+treaty (including future time extensions), (iii) in any current or future
+medium and for any number of copies, and (iv) for any purpose whatsoever,
+including without limitation commercial, advertising or promotional
+purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each
+member of the public at large and to the detriment of Affirmer's heirs and
+successors, fully intending that such Waiver shall not be subject to
+revocation, rescission, cancellation, termination, or any other legal or
+equitable action to disrupt the quiet enjoyment of the Work by the public
+as contemplated by Affirmer's express Statement of Purpose.
+
+3. Public License Fallback. Should any part of the Waiver for any reason
+be judged legally invalid or ineffective under applicable law, then the
+Waiver shall be preserved to the maximum extent permitted taking into
+account Affirmer's express Statement of Purpose. In addition, to the
+extent the Waiver is so judged Affirmer hereby grants to each affected
+person a royalty-free, non transferable, non sublicensable, non exclusive,
+irrevocable and unconditional license to exercise Affirmer's Copyright and
+Related Rights in the Work (i) in all territories worldwide, (ii) for the
+maximum duration provided by applicable law or treaty (including future
+time extensions), (iii) in any current or future medium and for any number
+of copies, and (iv) for any purpose whatsoever, including without
+limitation commercial, advertising or promotional purposes (the
+"License"). The License shall be deemed effective as of the date CC0 was
+applied by Affirmer to the Work. Should any part of the License for any
+reason be judged legally invalid or ineffective under applicable law, such
+partial invalidity or ineffectiveness shall not invalidate the remainder
+of the License, and in such case Affirmer hereby affirms that he or she
+will not (i) exercise any of his or her remaining Copyright and Related
+Rights in the Work or (ii) assert any associated claims and causes of
+action with respect to the Work, in either case contrary to Affirmer's
+express Statement of Purpose.
+
+4. Limitations and Disclaimers.
+
+ a. No trademark or patent rights held by Affirmer are waived, abandoned,
+ surrendered, licensed or otherwise affected by this document.
+ b. Affirmer offers the Work as-is and makes no representations or
+ warranties of any kind concerning the Work, express, implied,
+ statutory or otherwise, including without limitation warranties of
+ title, merchantability, fitness for a particular purpose, non
+ infringement, or the absence of latent or other defects, accuracy, or
+ the present or absence of errors, whether or not discoverable, all to
+ the greatest extent permissible under applicable law.
+ c. Affirmer disclaims responsibility for clearing rights of other persons
+ that may apply to the Work or any use thereof, including without
+ limitation any person's Copyright and Related Rights in the Work.
+ Further, Affirmer disclaims responsibility for obtaining any necessary
+ consents, permissions or other rights required for any use of the
+ Work.
+ d. Affirmer understands and acknowledges that Creative Commons is not a
+ party to this document and has no duty or obligation with respect to
+ this CC0 or use of the Work.
diff --git a/Yackovlev/COPYING.LESSER b/Yackovlev/COPYING.LESSER
new file mode 100644
index 00000000..0a041280
--- /dev/null
+++ b/Yackovlev/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.
+
+
+ This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+ 0. Additional Definitions.
+
+ As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
+ "The Library" refers to a covered work governed by this License,
+other than an Application or a Combined Work as defined below.
+
+ An "Application" is any work that makes use of an interface provided
+by the Library, but which is not otherwise based on the Library.
+Defining a subclass of a class defined by the Library is deemed a mode
+of using an interface provided by the Library.
+
+ A "Combined Work" is a work produced by combining or linking an
+Application with the Library. The particular version of the Library
+with which the Combined Work was made is also called the "Linked
+Version".
+
+ The "Minimal Corresponding Source" for a Combined Work means the
+Corresponding Source for the Combined Work, excluding any source code
+for portions of the Combined Work that, considered in isolation, are
+based on the Application, and not on the Linked Version.
+
+ The "Corresponding Application Code" for a Combined Work means the
+object code and/or source code for the Application, including any data
+and utility programs needed for reproducing the Combined Work from the
+Application, but excluding the System Libraries of the Combined Work.
+
+ 1. Exception to Section 3 of the GNU GPL.
+
+ You may convey a covered work under sections 3 and 4 of this License
+without being bound by section 3 of the GNU GPL.
+
+ 2. Conveying Modified Versions.
+
+ If you modify a copy of the Library, and, in your modifications, a
+facility refers to a function or data to be supplied by an Application
+that uses the facility (other than as an argument passed when the
+facility is invoked), then you may convey a copy of the modified
+version:
+
+ a) under this License, provided that you make a good faith effort to
+ ensure that, in the event an Application does not supply the
+ function or data, the facility still operates, and performs
+ whatever part of its purpose remains meaningful, or
+
+ b) under the GNU GPL, with none of the additional permissions of
+ this License applicable to that copy.
+
+ 3. Object Code Incorporating Material from Library Header Files.
+
+ The object code form of an Application may incorporate material from
+a header file that is part of the Library. You may convey such object
+code under terms of your choice, provided that, if the incorporated
+material is not limited to numerical parameters, data structure
+layouts and accessors, or small macros, inline functions and templates
+(ten or fewer lines in length), you do both of the following:
+
+ a) Give prominent notice with each copy of the object code that the
+ Library is used in it and that the Library and its use are
+ covered by this License.
+
+ b) Accompany the object code with a copy of the GNU GPL and this license
+ document.
+
+ 4. Combined Works.
+
+ You may convey a Combined Work under terms of your choice that,
+taken together, effectively do not restrict modification of the
+portions of the Library contained in the Combined Work and reverse
+engineering for debugging such modifications, if you also do each of
+the following:
+
+ a) Give prominent notice with each copy of the Combined Work that
+ the Library is used in it and that the Library and its use are
+ covered by this License.
+
+ b) Accompany the Combined Work with a copy of the GNU GPL and this license
+ document.
+
+ c) For a Combined Work that displays copyright notices during
+ execution, include the copyright notice for the Library among
+ these notices, as well as a reference directing the user to the
+ copies of the GNU GPL and this license document.
+
+ d) Do one of the following:
+
+ 0) Convey the Minimal Corresponding Source under the terms of this
+ License, and the Corresponding Application Code in a form
+ suitable for, and under terms that permit, the user to
+ recombine or relink the Application with a modified version of
+ the Linked Version to produce a modified Combined Work, in the
+ manner specified by section 6 of the GNU GPL for conveying
+ Corresponding Source.
+
+ 1) Use a suitable shared library mechanism for linking with the
+ Library. A suitable mechanism is one that (a) uses at run time
+ a copy of the Library already present on the user's computer
+ system, and (b) will operate properly with a modified version
+ of the Library that is interface-compatible with the Linked
+ Version.
+
+ e) Provide Installation Information, but only if you would otherwise
+ be required to provide such information under section 6 of the
+ GNU GPL, and only to the extent that such information is
+ necessary to install and execute a modified version of the
+ Combined Work produced by recombining or relinking the
+ Application with a modified version of the Linked Version. (If
+ you use option 4d0, the Installation Information must accompany
+ the Minimal Corresponding Source and Corresponding Application
+ Code. If you use option 4d1, you must provide the Installation
+ Information in the manner specified by section 6 of the GNU GPL
+ for conveying Corresponding Source.)
+
+ 5. Combined Libraries.
+
+ You may place library facilities that are a work based on the
+Library side by side in a single library together with other library
+facilities that are not Applications and are not covered by this
+License, and convey such a combined library under terms of your
+choice, if you do both of the following:
+
+ a) Accompany the combined library with a copy of the same work based
+ on the Library, uncombined with any other library facilities,
+ conveyed under the terms of this License.
+
+ b) Give prominent notice with the combined library that part of it
+ is a work based on the Library, and explaining where to find the
+ accompanying uncombined form of the same work.
+
+ 6. Revised Versions of the GNU Lesser General Public License.
+
+ The Free Software Foundation may publish revised and/or new versions
+of the GNU Lesser General Public License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the
+Library as you received it specifies that a certain numbered version
+of the GNU Lesser General Public License "or any later version"
+applies to it, you have the option of following the terms and
+conditions either of that published version or of any later version
+published by the Free Software Foundation. If the Library as you
+received it does not specify a version number of the GNU Lesser
+General Public License, you may choose any version of the GNU Lesser
+General Public License ever published by the Free Software Foundation.
+
+ If the Library as you received it specifies that a proxy can decide
+whether future versions of the GNU Lesser General Public License shall
+apply, that proxy's public statement of acceptance of any version is
+permanent authorization for you to choose that version for the
+Library.
diff --git a/Yackovlev/Makefile b/Yackovlev/Makefile
new file mode 100644
index 00000000..3889c476
--- /dev/null
+++ b/Yackovlev/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) --expect lib/ --expect tests/
+
+.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/Yackovlev/Yackovlev.opam b/Yackovlev/Yackovlev.opam
new file mode 100644
index 00000000..159f8353
--- /dev/null
+++ b/Yackovlev/Yackovlev.opam
@@ -0,0 +1,41 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+version: "0.1"
+synopsis: "A simple interpreter for educational purposes"
+description:
+ "An educational implementation of an interpreter for a small programming language"
+maintainer: ["Yackovlev Nickolay "]
+authors: ["Yackovlev Nickolay "]
+license: "LGPL-3.0-or-later WITH OCaml-LGPL-linking-exception"
+homepage: "https://github.com/Kakadu/fp25"
+doc: "https://kakadu.github.io/fp25/docs/Lambda"
+bug-reports: "https://github.com/Kakadu/fp25"
+depends: [
+ "dune" {>= "3.7" & = "3.19.1"}
+ "angstrom" {= "0.16.0"}
+ "base"
+ "ppx_inline_test" {with-test}
+ "ppx_expect"
+ "ppx_deriving"
+ "bisect_ppx"
+ "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}
+ ]
+]
+pin-depends: [
+ ["ppx_deriving_qcheck.0.6" "git+https://github.com/c-cube/qcheck.git#42429bf06ba12373cad02b1404f50d0ad6238af5"]
+]
+# Don't edit '*.opam' file manually. Use 'dune b @install'
diff --git a/Yackovlev/Yackovlev.opam.template b/Yackovlev/Yackovlev.opam.template
new file mode 100644
index 00000000..480da691
--- /dev/null
+++ b/Yackovlev/Yackovlev.opam.template
@@ -0,0 +1,4 @@
+pin-depends: [
+ ["ppx_deriving_qcheck.0.6" "git+https://github.com/c-cube/qcheck.git#42429bf06ba12373cad02b1404f50d0ad6238af5"]
+]
+# Don't edit '*.opam' file manually. Use 'dune b @install'
diff --git a/Yackovlev/bin/REPL.ml b/Yackovlev/bin/REPL.ml
new file mode 100644
index 00000000..6e142921
--- /dev/null
+++ b/Yackovlev/bin/REPL.ml
@@ -0,0 +1,23 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Lambda_lib
+
+let main () =
+ let input = In_channel.input_all In_channel.stdin in
+ match Parser.parse input with
+ | Error (Parser.Parsing_error err) -> Format.printf "Error: %s\n%!" err
+ | Ok ast ->
+ Format.printf "%a\n%!" Printast.pp_named ast;
+ let fuel = 100_000 in
+ (match Interpret.eval Interpret.initial_env fuel ast with
+ | Ok (v, _fuel_left) -> Format.printf "%s\n%!" (Interpret.string_of_value v)
+ | Error err -> Format.printf "Error: %s\n%!" (Interpret.string_of_error err))
+;;
+
+let () = main ()
diff --git a/Yackovlev/bin/REPL.mli b/Yackovlev/bin/REPL.mli
new file mode 100644
index 00000000..5d00c653
--- /dev/null
+++ b/Yackovlev/bin/REPL.mli
@@ -0,0 +1,7 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
diff --git a/Yackovlev/bin/dune b/Yackovlev/bin/dune
new file mode 100644
index 00000000..a03fbc3b
--- /dev/null
+++ b/Yackovlev/bin/dune
@@ -0,0 +1,10 @@
+(executable
+ (name REPL)
+ (public_name REPL)
+ (modules REPL)
+ (libraries lambda_lib)
+ (instrumentation
+ (backend bisect_ppx)))
+
+(cram
+ (deps ./REPL.exe %{bin:REPL}))
diff --git a/Yackovlev/dune b/Yackovlev/dune
new file mode 100644
index 00000000..98e54536
--- /dev/null
+++ b/Yackovlev/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/Yackovlev/dune-project b/Yackovlev/dune-project
new file mode 100644
index 00000000..ed569084
--- /dev/null
+++ b/Yackovlev/dune-project
@@ -0,0 +1,41 @@
+(lang dune 3.7)
+
+(generate_opam_files true)
+
+(cram enable)
+
+(license "LGPL-3.0-or-later WITH OCaml-LGPL-linking-exception")
+
+(authors
+ "Yackovlev Nickolay ")
+
+(maintainers "Yackovlev Nickolay ")
+
+(bug_reports "https://github.com/Kakadu/fp25")
+
+(homepage "https://github.com/Kakadu/fp25")
+
+(package
+ (name Yackovlev)
+ (synopsis "A simple interpreter for educational purposes")
+ (description "An educational implementation of an interpreter for a small programming language")
+ (documentation "https://kakadu.github.io/fp25/docs/Lambda")
+ (version 0.1)
+ (depends
+ (dune
+ (= "3.19.1"))
+ (angstrom
+ (= "0.16.0"))
+ base
+ (ppx_inline_test :with-test)
+ ppx_expect
+ ppx_deriving
+ bisect_ppx
+ (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/Yackovlev/lib/Printast.ml b/Yackovlev/lib/Printast.ml
new file mode 100644
index 00000000..aa9ad272
--- /dev/null
+++ b/Yackovlev/lib/Printast.ml
@@ -0,0 +1,46 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Format
+open Ast
+
+let string_of_unop = function
+ | Neg -> "-"
+;;
+
+let string_of_binop = function
+ | Add -> "+"
+ | Sub -> "-"
+ | Mul -> "*"
+ | Div -> "/"
+;;
+
+let string_of_cmpop = function
+ | Eq -> "="
+ | Neq -> "<>"
+ | Lt -> "<"
+ | Le -> "<="
+ | Gt -> ">"
+ | Ge -> ">="
+;;
+
+let rec pp fmt = function
+ | Var x -> pp_print_string fmt x
+ | Int n -> fprintf fmt "%d" n
+ | Abs (x, e) -> fprintf fmt "(fun %s -> %a)" x pp e
+ | App (e1, e2) -> fprintf fmt "(%a %a)" pp e1 pp e2
+ | Let (x, e1, e2) -> fprintf fmt "(let %s = %a in %a)" x pp e1 pp e2
+ | Let_rec (f, e1, e2) -> fprintf fmt "(let rec %s = %a in %a)" f pp e1 pp e2
+ | If (cond, t, e) -> fprintf fmt "(if %a then %a else %a)" pp cond pp t pp e
+ | Unop (op, e) -> fprintf fmt "(%s%a)" (string_of_unop op) pp e
+ | Binop (op, e1, e2) -> fprintf fmt "(%a %s %a)" pp e1 (string_of_binop op) pp e2
+ | Cmp (op, e1, e2) -> fprintf fmt "(%a %s %a)" pp e1 (string_of_cmpop op) pp e2
+;;
+
+let pp_named = pp
+let show ast = asprintf "%a" pp ast
diff --git a/Yackovlev/lib/Printast.mli b/Yackovlev/lib/Printast.mli
new file mode 100644
index 00000000..d4fa96b8
--- /dev/null
+++ b/Yackovlev/lib/Printast.mli
@@ -0,0 +1,11 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+val pp_named : Format.formatter -> Ast.expr -> unit
+val pp : Format.formatter -> Ast.expr -> unit
+val show : Ast.expr -> string
diff --git a/Yackovlev/lib/ast.mli b/Yackovlev/lib/ast.mli
new file mode 100644
index 00000000..12b34bc6
--- /dev/null
+++ b/Yackovlev/lib/ast.mli
@@ -0,0 +1,38 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+type name = string
+type unop = Neg (** -e *)
+
+type binop =
+ | Add (** e1 + e2 *)
+ | Sub (** e1 - e2 *)
+ | Mul (** e1 * e2 *)
+ | Div (** e1 / e2 *)
+
+type cmpop =
+ | Eq (** e1 = e2 *)
+ | Neq (** e1 <> e2 *)
+ | Lt (** e1 < e2 *)
+ | Le (** e1 <= e2 *)
+ | Gt (** e1 > e2 *)
+ | Ge (** e1 >= e2 *)
+
+type expr =
+ | Var of name (** Variable, like x *)
+ | Int of int (** Integer literal *)
+ | Abs of name * expr (** Function: fun x -> e *)
+ | App of expr * expr (** Function application: e1 e2 *)
+ | Let of name * expr * expr (** Non-recursive let: let x = e1 in e2 *)
+ | Let_rec of name * expr * expr (** Recursive let: let rec f = e1 in e2 *)
+ | If of expr * expr * expr (** If expression *)
+ | Unop of unop * expr (** Unary operation *)
+ | Binop of binop * expr * expr (** Arithmetic operation *)
+ | Cmp of cmpop * expr * expr (** Comparison *)
+
+type program = expr
diff --git a/Yackovlev/lib/dune b/Yackovlev/lib/dune
new file mode 100644
index 00000000..871190a3
--- /dev/null
+++ b/Yackovlev/lib/dune
@@ -0,0 +1,10 @@
+(library
+ (name lambda_lib)
+ (public_name Yackovlev.Lib)
+ (modules Ast Interpret Parser Printast)
+ (modules_without_implementation ast)
+ (libraries base angstrom)
+ (preprocess
+ (pps ppx_deriving.show))
+ (instrumentation
+ (backend bisect_ppx)))
diff --git a/Yackovlev/lib/interpret.ml b/Yackovlev/lib/interpret.ml
new file mode 100644
index 00000000..fc6d9b69
--- /dev/null
+++ b/Yackovlev/lib/interpret.ml
@@ -0,0 +1,166 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Ast
+
+type prim =
+ | Print_int
+ | Fix
+
+type value =
+ | VInt of int
+ | VClosure of closure
+ | VPrim of prim
+ | VUnit
+
+and closure =
+ { param : name
+ ; body : expr
+ ; env : env
+ }
+
+and env = (name * value) list
+
+type error =
+ | Unknown_variable of name
+ | Not_a_function of value
+ | Div_by_zero
+ | Type_error of string
+ | Out_of_fuel
+
+type 'a eval_result = ('a, error) result
+
+let ok x = Ok x
+let error e = Error e
+
+let ( let* ) (m : 'a eval_result) (f : 'a -> 'b eval_result) : 'b eval_result =
+ match m with
+ | Ok v -> f v
+ | Error e -> Error e
+;;
+
+type fuel = int
+
+let tick (fuel : fuel) : (unit * fuel, error) result =
+ if fuel <= 0 then error Out_of_fuel else ok ((), fuel - 1)
+;;
+
+let lookup (env : env) (x : name) : value option = List.assoc_opt x env
+
+let string_of_value = function
+ | VInt n -> string_of_int n
+ | VUnit -> "()"
+ | VClosure _ -> ""
+ | VPrim Print_int -> ""
+ | VPrim Fix -> ""
+;;
+
+let string_of_error : error -> string = function
+ | Unknown_variable x -> "Unknown variable: " ^ x
+ | Not_a_function v -> "Not a function: " ^ string_of_value v
+ | Div_by_zero -> "Division by zero"
+ | Type_error msg -> "Type error: " ^ msg
+ | Out_of_fuel -> "Out of fuel"
+;;
+
+let rec apply (fuel : fuel) (f : value) (arg : value) : (value * fuel, error) result =
+ match f with
+ | VClosure { param; body; env } ->
+ let env' = (param, arg) :: env in
+ eval env' fuel body
+ | VPrim Print_int ->
+ (match arg with
+ | VInt n ->
+ print_endline (string_of_int n);
+ ok (VUnit, fuel)
+ | v -> error (Type_error ("print_int expects int, got " ^ string_of_value v)))
+ | VPrim Fix ->
+ (match arg with
+ | VClosure { param = self; body; env } ->
+ (match body with
+ | Abs (arg, inner_body) ->
+ let rec rec_closure =
+ VClosure { param = arg; body = inner_body; env = (self, rec_closure) :: env }
+ in
+ ok (rec_closure, fuel)
+ | _ -> error (Type_error "fix expects a function that returns a function"))
+ | v -> error (Type_error ("fix expects a function, got " ^ string_of_value v)))
+ | v -> error (Not_a_function v)
+
+and eval (env : env) (fuel : fuel) (e : expr) : (value * fuel, error) result =
+ let* (), fuel = tick fuel in
+ match e with
+ | Var x ->
+ (match lookup env x with
+ | Some v -> ok (v, fuel)
+ | None -> error (Unknown_variable x))
+ | Int n -> ok (VInt n, fuel)
+ | Abs (x, body) -> ok (VClosure { param = x; body; env }, fuel)
+ | App (e1, e2) ->
+ let* f, fuel1 = eval env fuel e1 in
+ let* arg, fuel2 = eval env fuel1 e2 in
+ apply fuel2 f arg
+ | Let (x, e1, e2) ->
+ let* v1, fuel1 = eval env fuel e1 in
+ let env' = (x, v1) :: env in
+ eval env' fuel1 e2
+ | Let_rec (f, rhs, body) ->
+ (match rhs with
+ | Abs (x, fun_body) ->
+ let rec closure = VClosure { param = x; body = fun_body; env = env' }
+ and env' = (f, closure) :: env in
+ eval env' fuel body
+ | _ -> error (Type_error "let rec expects a function on the right-hand side"))
+ | If (cond, e_then, e_else) ->
+ let* v_cond, fuel1 = eval env fuel cond in
+ (match v_cond with
+ | VInt n -> if n <> 0 then eval env fuel1 e_then else eval env fuel1 e_else
+ | _ -> error (Type_error "if condition must be an int"))
+ | Unop (op, e1) ->
+ let* v1, fuel1 = eval env fuel e1 in
+ (match v1 with
+ | VInt n ->
+ let res =
+ match op with
+ | Neg -> -n
+ in
+ ok (VInt res, fuel1)
+ | _ -> error (Type_error "integer operand expected in unary operation"))
+ | Binop (op, e1, e2) ->
+ let* v1, fuel1 = eval env fuel e1 in
+ let* v2, fuel2 = eval env fuel1 e2 in
+ (match v1, v2 with
+ | VInt n1, VInt n2 ->
+ let* n =
+ match op with
+ | Add -> ok (n1 + n2)
+ | Sub -> ok (n1 - n2)
+ | Mul -> ok (n1 * n2)
+ | Div -> if n2 = 0 then error Div_by_zero else ok (n1 / n2)
+ in
+ ok (VInt n, fuel2)
+ | _ -> error (Type_error "integer operands expected in arithmetic"))
+ | Cmp (op, e1, e2) ->
+ let* v1, fuel1 = eval env fuel e1 in
+ let* v2, fuel2 = eval env fuel1 e2 in
+ (match v1, v2 with
+ | VInt n1, VInt n2 ->
+ let b =
+ match op with
+ | Eq -> n1 = n2
+ | Neq -> n1 <> n2
+ | Lt -> n1 < n2
+ | Le -> n1 <= n2
+ | Gt -> n1 > n2
+ | Ge -> n1 >= n2
+ in
+ ok (VInt (if b then 1 else 0), fuel2)
+ | _ -> error (Type_error "comparison expects integer operands"))
+;;
+
+let initial_env : env = [ "print_int", VPrim Print_int; "fix", VPrim Fix ]
diff --git a/Yackovlev/lib/interpret.mli b/Yackovlev/lib/interpret.mli
new file mode 100644
index 00000000..616af5da
--- /dev/null
+++ b/Yackovlev/lib/interpret.mli
@@ -0,0 +1,48 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+open Ast
+
+type prim =
+ | Print_int
+ | Fix
+
+type value =
+ | VInt of int
+ | VClosure of closure
+ | VPrim of prim
+ | VUnit
+
+and closure =
+ { param : name
+ ; body : expr
+ ; env : env
+ }
+
+and env = (name * value) list
+
+type error =
+ | Unknown_variable of name
+ | Not_a_function of value
+ | Div_by_zero
+ | Type_error of string
+ | Out_of_fuel
+
+type 'a eval_result = ('a, error) result
+
+val ok : 'a -> 'a eval_result
+val error : error -> 'a eval_result
+val ( let* ) : 'a eval_result -> ('a -> 'b eval_result) -> 'b eval_result
+
+type fuel = int
+
+val tick : fuel -> (unit * fuel, error) result
+val eval : env -> fuel -> expr -> (value * fuel, error) result
+val initial_env : env
+val string_of_value : value -> string
+val string_of_error : error -> string
diff --git a/Yackovlev/lib/parser.ml b/Yackovlev/lib/parser.ml
new file mode 100644
index 00000000..772cd7dd
--- /dev/null
+++ b/Yackovlev/lib/parser.ml
@@ -0,0 +1,145 @@
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+open Angstrom
+
+let is_space = function
+ | ' ' | '\t' | '\n' | '\r' -> true
+ | _ -> false
+;;
+
+let spaces = skip_while is_space
+let token p = p <* spaces
+let symbol s = token (string s)
+let parens p = symbol "(" *> p <* symbol ")"
+
+let is_ident_start = function
+ | 'a' .. 'z' | '_' -> true
+ | _ -> false
+;;
+
+let is_ident_char = function
+ | 'a' .. 'z' | 'A' .. 'Z' | '0' .. '9' | '_' | '\'' -> true
+ | _ -> false
+;;
+
+let ident_raw =
+ satisfy is_ident_start
+ >>= fun first -> take_while is_ident_char >>| fun rest -> String.make 1 first ^ rest
+;;
+
+let keywords = [ "let"; "rec"; "in"; "fun"; "if"; "then"; "else" ]
+
+let keyword s =
+ token ident_raw
+ >>= fun id -> if id = s then return () else fail ("Expected keyword " ^ s)
+;;
+
+let ident =
+ token ident_raw
+ >>= fun s ->
+ if List.mem s keywords then fail "Keyword cannot be used as identifier" else return s
+;;
+
+let integer =
+ take_while1 (function
+ | '0' .. '9' -> true
+ | _ -> false)
+ >>| int_of_string
+ |> token
+;;
+
+type error = Parsing_error of string
+
+let expr : Ast.expr Angstrom.t =
+ let open Ast in
+ fix (fun expr ->
+ let chainl1 p op =
+ p
+ >>= fun init ->
+ many (op >>= fun f -> p >>| fun v -> f, v)
+ >>| fun rest -> List.fold_left (fun acc (f, v) -> f acc v) init rest
+ in
+ let atom =
+ choice [ parens expr; (integer >>| fun n -> Int n); (ident >>| fun x -> Var x) ]
+ in
+ let app =
+ atom
+ >>= fun first ->
+ many atom >>| fun rest -> List.fold_left (fun acc r -> App (acc, r)) first rest
+ in
+ let unary =
+ fix (fun self -> choice [ (symbol "-" *> self >>| fun e -> Unop (Neg, e)); app ])
+ in
+ let mul_div =
+ let op =
+ choice
+ [ symbol "*" *> return (fun l r -> Binop (Mul, l, r))
+ ; symbol "/" *> return (fun l r -> Binop (Div, l, r))
+ ]
+ in
+ chainl1 unary op
+ in
+ let add_sub =
+ let op =
+ choice
+ [ symbol "+" *> return (fun l r -> Binop (Add, l, r))
+ ; symbol "-" *> return (fun l r -> Binop (Sub, l, r))
+ ]
+ in
+ chainl1 mul_div op
+ in
+ let cmp =
+ let op =
+ choice
+ [ symbol "=" *> return (fun l r -> Cmp (Eq, l, r))
+ ; symbol "<>" *> return (fun l r -> Cmp (Neq, l, r))
+ ; symbol "<=" *> return (fun l r -> Cmp (Le, l, r))
+ ; symbol ">=" *> return (fun l r -> Cmp (Ge, l, r))
+ ; symbol "<" *> return (fun l r -> Cmp (Lt, l, r))
+ ; symbol ">" *> return (fun l r -> Cmp (Gt, l, r))
+ ]
+ in
+ chainl1 add_sub op
+ in
+ let make_fun params body = List.fold_right (fun x acc -> Abs (x, acc)) params body in
+ let fun_expr =
+ keyword "fun" *> many1 ident
+ >>= fun params -> symbol "->" *> expr >>| fun body -> make_fun params body
+ in
+ let if_expr =
+ keyword "if" *> expr
+ >>= fun cond ->
+ keyword "then" *> expr
+ >>= fun then_ -> keyword "else" *> expr >>| fun else_ -> If (cond, then_, else_)
+ in
+ let let_expr =
+ keyword "let" *> token ident_raw
+ >>= fun next_token ->
+ let is_rec = next_token = "rec" in
+ (if is_rec
+ then ident
+ else if List.mem next_token keywords
+ then fail "Keyword used as variable name"
+ else return next_token)
+ >>= fun name ->
+ many ident
+ >>= fun params ->
+ symbol "=" *> expr
+ >>= fun rhs ->
+ keyword "in" *> expr
+ >>| fun body ->
+ let rhs' = make_fun params rhs in
+ if is_rec then Let_rec (name, rhs', body) else Let (name, rhs', body)
+ in
+ choice [ let_expr; if_expr; fun_expr; cmp ])
+;;
+
+let parse str =
+ match
+ Angstrom.parse_string (spaces *> expr <* spaces) ~consume:Angstrom.Consume.All str
+ with
+ | Result.Ok x -> Result.Ok x
+ | Error er -> Result.Error (Parsing_error er)
+;;
diff --git a/Yackovlev/lib/parser.mli b/Yackovlev/lib/parser.mli
new file mode 100644
index 00000000..f0a1a313
--- /dev/null
+++ b/Yackovlev/lib/parser.mli
@@ -0,0 +1,11 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]
+
+type error = Parsing_error of string
+
+val parse : string -> (Ast.expr, error) result
diff --git a/Yackovlev/tests/.gitignore b/Yackovlev/tests/.gitignore
new file mode 100644
index 00000000..26685e79
--- /dev/null
+++ b/Yackovlev/tests/.gitignore
@@ -0,0 +1 @@
+lam*.txt
\ No newline at end of file
diff --git a/Yackovlev/tests/dune b/Yackovlev/tests/dune
new file mode 100644
index 00000000..02ac7830
--- /dev/null
+++ b/Yackovlev/tests/dune
@@ -0,0 +1,10 @@
+(test
+ (name parser_test)
+ (libraries lambda_lib qcheck)
+ (modules parser_test)
+ (instrumentation
+ (backend bisect_ppx)))
+
+(cram
+ (applies_to interpret_tests)
+ (deps ../bin/REPL.exe))
diff --git a/Yackovlev/tests/interpret_tests.t b/Yackovlev/tests/interpret_tests.t
new file mode 100644
index 00000000..a1601bf2
--- /dev/null
+++ b/Yackovlev/tests/interpret_tests.t
@@ -0,0 +1,183 @@
+Copyright 2021-2026, Kakadu and Yackovlev Nickolay
+SPDX-License-Identifier: CC0-1.0
+
+ $ REPL=./../bin/REPL.exe
+
+ $ $REPL < 1 + 2 * 3
+ (1 + (2 * 3))
+ 7
+
+ $ $REPL < 20 / 2
+ (20 / 2)
+ 10
+
+ $ $REPL < -(1 + 2)
+ (-(1 + 2))
+ -3
+
+ $ $REPL < 1 = 1
+ (1 = 1)
+ 1
+
+ $ $REPL < 1 <> 2
+ (1 <> 2)
+ 1
+
+ $ $REPL < 5 > 10
+ (5 > 10)
+ 0
+
+ $ $REPL < 5 >= 10
+ (5 >= 10)
+ 0
+
+ $ printf "1 \r\t + 2\n" | $REPL
+ (1 + 2)
+ 3
+
+ $ $REPL < if 1 < 2 then 100 else 200
+ (if (1 < 2) then 100 else 200)
+ 100
+
+ $ $REPL < if 0 then 1 else 0
+ (if 0 then 1 else 0)
+ 0
+
+ $ $REPL < let x = 5 in let y = x + 1 in x * y
+ (let x = 5 in (let y = (x + 1) in (x * y)))
+ 30
+
+ $ $REPL < let f = fun x y z -> x + y + z in f 1 2 3
+ (let f = (fun x -> (fun y -> (fun z -> ((x + y) + z)))) in (((f 1) 2) 3))
+ 6
+
+ $ $REPL < print_int 0
+ (print_int 0)
+ 0
+ ()
+
+ $ $REPL < let _ = print_int 999 in 0
+ (let _ = (print_int 999) in 0)
+ 999
+ 0
+
+ $ $REPL < print_int
+ print_int
+
+
+ $ $REPL < fix
+ fix
+
+
+ $ $REPL < let rec fact n = if n <= 1 then 1 else n * fact (n - 1) in fact 5
+ (let rec fact = (fun n -> (if (n <= 1) then 1 else (n * (fact (n - 1))))) in (fact 5))
+ 120
+
+ $ $REPL < let rec fib n = if n <= 1 then n else fib (n-1) + fib (n-2) in fib 10
+ (let rec fib = (fun n -> (if (n <= 1) then n else ((fib (n - 1)) + (fib (n - 2))))) in (fib 10))
+ 55
+
+ $ $REPL < let fact = fix (fun self -> fun n -> if n = 0 then 1 else n * self (n - 1)) in fact 5
+ (let fact = (fix (fun self -> (fun n -> (if (n = 0) then 1 else (n * (self (n - 1))))))) in (fact 5))
+ 120
+
+ $ $REPL < let rec loop x = loop x in loop 0
+ (let rec loop = (fun x -> (loop x)) in (loop 0))
+ Error: Out of fuel
+
+ $ $REPL < 10 / 0
+ (10 / 0)
+ Error: Division by zero
+
+ $ $REPL < unknown_var
+ unknown_var
+ Error: Unknown variable: unknown_var
+
+ $ $REPL < let x = 5 in x 10
+ (let x = 5 in (x 10))
+ Error: Not a function: 5
+
+ $ $REPL < (fun x -> x) + 1
+ ((fun x -> x) + 1)
+ Error: Type error: integer operands expected in arithmetic
+
+ $ $REPL < if (fun x -> x) then 1 else 0
+ (if (fun x -> x) then 1 else 0)
+ Error: Type error: if condition must be an int
+
+ $ $REPL < (fun x -> x) > 0
+ ((fun x -> x) > 0)
+ Error: Type error: comparison expects integer operands
+
+ $ $REPL < print_int (fun x -> x)
+ (print_int (fun x -> x))
+ Error: Type error: print_int expects int, got
+
+ $ $REPL < fix 5
+ (fix 5)
+ Error: Type error: fix expects a function, got 5
+
+ $ $REPL < fix (fun x -> 1)
+ (fix (fun x -> 1))
+ Error: Type error: fix expects a function that returns a function
+
+ $ $REPL < let rec x = 5 in x
+ (let rec x = 5 in x)
+ Error: Type error: let rec expects a function on the right-hand side
+
+ $ $REPL < 1 + * 2
+ Error: : end_of_input
+
+ $ $REPL < -(fun x -> x)
+ (-(fun x -> x))
+ Error: Type error: integer operand expected in unary operation
+
+ $ $REPL < let if = 5 in 1
+ Error: : no more choices
+
+ $ $REPL < letx = 0 in x
+ Error: : end_of_input
+
+ $ $REPL < let x = 0 in(x)
+ (let x = 0 in x)
+ 0
+
+ $ $REPL < let fix = fun f -> (fun x -> f (fun eta -> x x eta)) (fun x -> f (fun eta -> x x eta)) in
+ > let fact = fun self n -> if n <= 1 then 1 else n * self (n - 1) in fix fact 5
+ (let fix = (fun f -> ((fun x -> (f (fun eta -> ((x x) eta)))) (fun x -> (f (fun eta -> ((x x) eta)))))) in (let fact = (fun self -> (fun n -> (if (n <= 1) then 1 else (n * (self (n - 1)))))) in ((fix fact) 5)))
+ 120
diff --git a/Yackovlev/tests/parser_test.ml b/Yackovlev/tests/parser_test.ml
new file mode 100644
index 00000000..12477c5f
--- /dev/null
+++ b/Yackovlev/tests/parser_test.ml
@@ -0,0 +1,119 @@
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+open Lambda_lib
+open Ast
+
+let gen_name =
+ let open QCheck.Gen in
+ oneof_list [ "x"; "y"; "z"; "a"; "b"; "aB"; "x1"; "y_2"; "n'"; "fact"; "fib" ]
+;;
+
+let gen_binop =
+ let open QCheck.Gen in
+ oneof_list [ Add; Sub; Mul; Div ]
+;;
+
+let gen_cmpop =
+ let open QCheck.Gen in
+ oneof_list [ Eq; Neq; Lt; Le; Gt; Ge ]
+;;
+
+let gen_unop =
+ let open QCheck.Gen in
+ oneof_list [ Neg ]
+;;
+
+let gen_expr =
+ let open QCheck.Gen in
+ let rec expr depth =
+ delay (fun () ->
+ if depth <= 0
+ then oneof [ map (fun i -> Int i) (int_range 0 100); map (fun s -> Var s) gen_name ]
+ else (
+ let new_depth = depth - 1 in
+ oneof_weighted
+ [ 3, map (fun i -> Int i) (int_range 0 100)
+ ; 3, map (fun s -> Var s) gen_name
+ ; 1, map2 (fun op e -> Unop (op, e)) gen_unop (expr new_depth)
+ ; ( 1
+ , map3
+ (fun op l r -> Binop (op, l, r))
+ gen_binop
+ (expr new_depth)
+ (expr new_depth) )
+ ; ( 1
+ , map3
+ (fun op l r -> Cmp (op, l, r))
+ gen_cmpop
+ (expr new_depth)
+ (expr new_depth) )
+ ; 1, map2 (fun name body -> Abs (name, body)) gen_name (expr new_depth)
+ ; 2, map2 (fun e1 e2 -> App (e1, e2)) (expr new_depth) (expr new_depth)
+ ; ( 1
+ , map3
+ (fun c t e -> If (c, t, e))
+ (expr new_depth)
+ (expr new_depth)
+ (expr new_depth) )
+ ; ( 1
+ , map3
+ (fun x e1 e2 -> Let (x, e1, e2))
+ gen_name
+ (expr new_depth)
+ (expr new_depth) )
+ ; ( 1
+ , map3
+ (fun x e1 e2 -> Let_rec (x, e1, e2))
+ gen_name
+ (expr new_depth)
+ (expr new_depth) )
+ ]))
+ in
+ sized (fun n -> expr (min n 5))
+;;
+
+let print_expr e = Printast.show e
+let arbitrary_expr = QCheck.make ~print:print_expr gen_expr
+
+let test_print_parse_roundtrip =
+ QCheck.Test.make
+ ~count:100
+ ~name:"Roundtrip: Parse(Print(e)) == e"
+ arbitrary_expr
+ (fun ast ->
+ let str = print_expr ast in
+ match Parser.parse str with
+ | Ok ast' -> ast = ast'
+ | Error _ -> false)
+;;
+
+let test_printer_safety =
+ QCheck.Test.make ~count:100 ~name:"Printer Safety" arbitrary_expr (fun ast ->
+ try
+ let _ = print_expr ast in
+ true
+ with
+ | _ -> false)
+;;
+
+let test_parser_negative =
+ let invalid_inputs =
+ [ ""; "let x ="; "1 +"; "if true then"; "fun -> x"; "let rec 1 = x" ]
+ in
+ let gen_invalid = QCheck.Gen.oneof_list invalid_inputs in
+ QCheck.Test.make
+ ~count:(List.length invalid_inputs)
+ ~name:"Negative Parser Tests"
+ (QCheck.make ~print:(fun s -> s) gen_invalid)
+ (fun str ->
+ match Parser.parse str with
+ | Error (Parser.Parsing_error _) -> true
+ | Ok _ -> false)
+;;
+
+let () =
+ let tests = [ test_print_parse_roundtrip; test_printer_safety; test_parser_negative ] in
+ QCheck_runner.run_tests_main tests
+;;
diff --git a/Yackovlev/tests/parser_test.mli b/Yackovlev/tests/parser_test.mli
new file mode 100644
index 00000000..5d00c653
--- /dev/null
+++ b/Yackovlev/tests/parser_test.mli
@@ -0,0 +1,7 @@
+[@@@ocaml.text "/*"]
+
+(** Copyright 2021-2026, Kakadu and Yackovlev Nickolay *)
+
+(** SPDX-License-Identifier: LGPL-3.0-or-later *)
+
+[@@@ocaml.text "/*"]