[HN Gopher] Compiler for the M language of the French DGFiP
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Compiler for the M language of the French DGFiP
Author : testcross
Score : 178 points
Date : 2020-10-09 16:11 UTC (6 hours ago)
(HTM) web link (gitlab.inria.fr)
(TXT) w3m dump (gitlab.inria.fr)
| boleary-gl wrote:
| GitLab team member here
|
| This is fantastic! If interested, you may want to check out our
| program for Open Source users of GitLab:
| https://about.gitlab.com/handbook/marketing/community-relati....
| [deleted]
| throwawaybutwhy wrote:
| Confused about inclusion of floating-point arithmetic in tax
| calculations [0]. Am I missing anything?
|
| [0]
| https://gitlab.inria.fr/verifisc/mlang/-/blob/master/formal_...
| whitten wrote:
| Calling your language the "M programming Language",
| unfortunately, is ambiguous. One of the oldest langauges to claim
| the name, is the MUMPS programming language used in healthcare
| computing and in financial computing is also called M (
| https://opensource.com/health/12/2/join-m-revolution ). The the
| Power Query Formula Programming Language is informally called the
| M programming language. Kiran S J of Bangalore has a language
| named the M Programming language
| (https://github.com/kiransj/m-programming-language) The Cache
| programming language is a super set of the M programming language
| ( https://cedocs.intersystems.com/latest/csp/docbook/Doc.View....
| ). Microsoft has a modeling language called the M Programming
| language (
| http://community.bartdesmet.net/blogs/bart/archive/2009/02/1... )
| There is the M# programming language (
| https://en.wikipedia.org/wiki/M_Sharp ) and the M programming
| language for language for HardWare description from
| MentorGraphics and The language for Mathematica, was called M,
| and now I think, is called the Wolfram Programming Language. (
| http://wiki.c2.com/?ProgrammingLanguageNamingPatterns )
| AshamedCaptain wrote:
| Doesn't matter. From a quick glance, no one would be able to
| distinguish MUMPS monstrosities from the monstrosities that are
| the tax .m files. Maybe this M and MUMPS are even related.
| glutamate wrote:
| Really interesting to see this. I'm a co-founder of AdviceBridge,
| where we have implemented part of the UK tax code related to
| income tax and pensions in order to provide digital financial
| advice.
|
| In the UK, the HMRC (again, equivalent of IRS) makes worksheets
| available for computational tax but these are not machine-
| readable and are not guaranteed to be correct! (Indeed on some
| points, government websites give incorrect information related to
| the state pension. [1])
|
| We did something similar to this approach but much simpler - we
| wrote a little arithmetic language specifying the tax rules,
| embedded in a spreadsheet for quick verification, and then
| translated this language into C++ using a Haskell compiler.
|
| [1]
| https://www.thisismoney.co.uk/money/pensions/article-7100019...
| Nextgrid wrote:
| Does HMRC provide those free of charge? I'd be curious to have
| a look at them.
| glutamate wrote:
| e.g. https://assets.publishing.service.gov.uk/government/uplo
| ads/...
| senstax wrote:
| Related: does anyone know if, by using these languages (Coq and
| OCaml), they've kept the door open to computer-assisted tax
| sensitivity analysis? E.g., I'm interested in outputting some
| kind of 2-dimensional or 3-dimensional solution space on 2, 3, or
| 4 input variables to identify discontinuities and slopes. Any
| thoughts?
|
| ETA: Diving into my thoughts on this a little: really what I'm
| describing would require (1) a dumb numerical analysis algorithm
| or (2) some CAS computer algebra system features, my preference.
| I don't know all the keywords and concepts, but I think term
| rewriting and equation solving would get me towards the output I
| seek: a multivariate, piecewise equation with user-selected input
| variables and user-selected output variables: e.g., current year
| tax, n+1 year tax, etc. Seems too involved, but ai have hope.
| remexre wrote:
| I think you'd want a differentiable language to make that easy.
| justinclift wrote:
| Something seems off with the current repo being pointed to. The
| repo Readme says: This work is based on a retro-
| engineering of the syntax and the semantics of M, from the
| codebase released by the DGFiP.
|
| Sounds like an external re-implementation, of the "original"
| release here:
|
| https://framagit.org/dgfip/ir-calcul
|
| That original release says it's under a free license too.
|
| Wonder why there's a re-implementation?
| noname120 wrote:
| The repo that you're linking to isn't an implementation of the
| M compiler. Rather it's the rules/definitions that are used to
| compute the income tax (<< Impot sur le Revenu >>).
|
| The M compiler reimplementation linked in this submission
| allows you to actually execute those rules and perform
| simulations.
| justinclift wrote:
| Thanks, that's good info. :)
| joelellis wrote:
| The author explains in the twitter thread (french):
|
| https://twitter.com/DMerigoux/status/1314531302079688709
|
| > The difficulty arose from a constraint on the part of the
| DGFiP which did not wish to publish, for security reasons, part
| of the logic of the calculation corresponding to the "multiple
| liquidations" mechanism. Raphael and I recreated this
| unpublished part in a new DSL.
|
| > The DGFiP also did not wish to publish its internal test
| sets. We therefore proceed to the creation of a completely
| random test set, from the unpublished content, in order to be
| able to reproduce the validation of Mlang outside the DGFiP.
|
| > A little less than a year after the publication of
| https://blog.merigoux.ovh/en/2019/12/20/taxes-formal-
| proofs...., we therefore found a compromise allowing to respect
| both the 'source code publication obligation, and the security
| constraints of the DGFiP.
|
| > By allowing us to go to its operating site and confidentially
| access the source code that it did not wish to publish, the
| DGFiP has enabled us to find alternative solutions that make
| the publication of the source code concrete and operational. .
| [deleted]
| kensai wrote:
| What is the German equivalent?
| cproctor wrote:
| I have implemented parts of the tax code, following 1040 and the
| network of forms it references line-by-line, for my own financial
| planning. I've been selective about what I implement based on
| what applies to me.
|
| I don't share the code because I'm not sufficiently confident
| that it's correct, don't want liability, and don't want an
| obligation to keep it up to date.
|
| That said, it feels like the scope of the project would be
| manageable for a small nonprofit, and would be of great social
| value. One reflection from my work is that it would be
| particularly valuable to represent annual changes in the tax code
| as transformations of the code AST.
| chromatin wrote:
| I understand your worry, but could you feel better offering it
| under a free software license that expressly disclaims
| warranties of usefulness for any purpose?
| jeffrallen wrote:
| Or leak it via Tor plus a pastebin, so that you are protected
| from liability via anonymity?
| fsflover wrote:
| Very good news. Consider signing the petition to make all
| publicly funded code free: https://publiccode.eu.
| jmole wrote:
| is there an initiative like this in the US?
| aloukissas wrote:
| Doubt it. The Intuit and HR Block lobbying dollars make sure
| our tax system is complicated enough to keep their businesses
| booming.
| j4nt4b wrote:
| Petitions are free, right? Unless it actually does exist,
| it makes sense to start one.
| fsflover wrote:
| This petition is made by Free Software Foundation Europe.
| I guess you should ask Free Software Foundation to start
| one in the US.
| j4nt4b wrote:
| Just sent an email. I'll update when I learn more.
| aloukissas wrote:
| This is cute, but this isn't how things work in the US.
| Money talks :)
| j4nt4b wrote:
| And though a tooth may bend the purest coin, remember too
| how gold will knead reason and virtue themselves like
| dough.
| beardyw wrote:
| I guess that's a quote. Where's it from?
| j4nt4b wrote:
| Me.
| joshspankit wrote:
| Don't forget the very lucrative business of "reducing tax
| exposure" where small firms get millions by knowing the
| smallest loopholes.
| Ericson2314 wrote:
| Code directly written be the Government must be public
| domain. I'm not sure this is a step in the right direction,
| or a step backwards as it just pushes more software
| engineering to consultants.
|
| (I've at least seen DARPA-funded work become open source.
| That's a good step.)
| cultus wrote:
| The big gotcha with that is that most government projects
| have collaborators in academia, NGOs, and/or industry. To a
| big extent, the public domain mandate doesn't apply if
| workers outside of the government contribute. Thus
| manuscripts or code often aren't public domain.
|
| edit: Also publishers _constantly_ "accidentally" claim
| copyright on public domain works (I'm looking at you,
| Elsevier). They never accidentally make something open-
| access.
| kazinator wrote:
| In the US, you calculate your own income tax, don't you? Like
| in Canada.
|
| The "source code" to the calculations are the paper forms
| which specify the calculations, making them transparent.
| santraginean wrote:
| People are downvoting without explaining, so I'll take a
| shot.
|
| First, yes, we calculate our own income tax, but the IRS
| also calculates it separately, and if the two disagree,
| they selectively decide whether to come knocking. (For
| example, they once tried to bill me $300,000 for a tax year
| when my net income was just over $100,000, because of
| multiple clerical errors -- we had sold a house, and they
| had both erroneously tried to apply capital gains tax where
| it didn't apply at all, and tried to tax us for the full
| sale price of the house as though we had bought it for $0
| and flipped it. It took months of back and forth to fix the
| issue, despite everything having been clearly documented.)
|
| Second, calculating tax liability is just the first step.
| Actually submitting tax returns electronically required a
| third party for a long time, and I believe it still does
| for all but the most straightforward returns. There's
| absolutely no reason for that to be the case, other than
| the outsize influence of lobbying money.
|
| That's without getting into all the loopholes, dodges, and
| hand-waving that make it possible for someone like Trump to
| avoid paying taxes entirely most years, while those of us
| who they know can't afford to lawyer up are the ones they
| try to collect from.
| kazinator wrote:
| > _if the two disagree_
|
| If the two disagree in a calculation matter, the
| calculations spelled out in the tax form should be upheld
| as the gold standard as to which side made the
| calculation error.
|
| > _they had both erroneously tried to apply capital gains
| tax where it didn 't apply at all_
|
| Was this issue due to paper tax forms doing a calculation
| one way, but the IRS's implementation doing it another
| way?
|
| Most recently, I screwed up by claiming a credit that was
| not allowed. However, the conditions for it are
| documented; I was wrong. This is where code could help,
| in order to clarify obtuse language in the requirements.
| Obviously, the government runs code which checks the
| conditions that determine whether a nonzero amount can be
| claimed in some field, so it's just another calculation.
| Still, it would be better for that to be crystal clear
| pseudo-code and not the fragment of some actual
| implementation.
| reaperducer wrote:
| _is there an initiative like this in the US?_
|
| It depends, and varies greatly by location.
|
| Anything created by the federal government is public domain
| by law. However, not all federal agencies make their code
| public. Some, understandably. Others, our of budget
| constraints or ignorance. In theory, you could file a FOIA
| request to get the code, assuming it's not classified.
|
| Other levels of government can be problematic. In part,
| because cities and towns can copyright things they create,
| while the federal government cannot.
|
| For example, the City of Chicago and some other cities have
| data portals open to the public. Their utility varies.
|
| Smaller cities, however, are less likely to understand the
| important or value of making data public.
|
| Back when governments started switching to data processing a
| lot, I belonged to an organization called Investigative
| Reporters and Editors. It had lots of guides for extracting
| data from local governments. I remember lots of newspapers
| rushing out to buy computers are nine-track tape readers so
| they could sort through the information.
| jeffrallen wrote:
| C'est toujours rigolo de trouver des noms francais pour les
| variables dans un program.
| maelito wrote:
| Bonne lecture ;)
|
| https://github.com/betagouv/mon-entreprise/blob/master/mon-e...
| jmnicolas wrote:
| program __me __:o
| lgvld wrote:
| C'est toujours rigolo de trouver un commentaire ecrit en
| francais sur HN. ;-)
| [deleted]
| bouzouk wrote:
| There is also a similar and very good project funded by the
| URSAAF and the DGFiP (the two main entities in the french tax
| system) : https://publi.codes
|
| IMO (I am not part of this project) it is more interesting as it
| is language agnostic, easy to use for everyone (based on yaml)
| and more importantly, it is starting to be implemented in the
| government actual tax computing system.
|
| We are using it in a challenger bank I started.
| maelito wrote:
| Related : the french administration has built a custom language
| for another big set of tax rules, those that dictate our social
| security system (which collects 500 billons of EUR / year)
|
| It's presented on https://publi.codes but unfortunately we've not
| translated it yet. The language keywords themselves are in
| french, by design, to bridge the law and its official
| implementation. It's not yet used to compute taxes, just to
| simulate them on the official mon-entreprise.fr website.
|
| The "code" expressed in YAML is parsed to build the computation
| model (in TypeScript), to document this model on the Web (each
| variable has a Web page) and to generate typeform-like forms.
|
| It's in the https://github.com/betagouv/mon-entreprise monorepo,
| but it's also used to implement a model of our personnal climate
| impact, here : https://github.com/betagouv/ecolab-
| data/tree/master/data
|
| Et bravo Denis :)
|
| Edit : in case you didn't know, the french adminstration's code
| must by law be made public. This is just the beginning, expect
| lots of similar projects ! You can browse some repos here
| https://code.etalab.gouv.fr
| littlestymaar wrote:
| > the french adminstration's code must by law be made public
|
| And this time, the code isn't printed on paper and send by post
| mails, which is a neat progress ;).
|
| See, https://www.nouvelobs.com/rue89/rue89-nos-vies-
| connectees/20... (in French) on how "making code public" was
| just a few years ago.
| aunetx wrote:
| That's funny because the INRIA is 5 minutes away from the place I
| am studying sciences right now, I did not think I would ever see
| them top in HN :)
| hansjorg wrote:
| They've been on the frontpage many times just the last year
| (click inria.fr after the post title to see all submissions
| linking there).
| ccktlmazeltov wrote:
| really? They're often on the frontpage.
| agumonkey wrote:
| unlike parent
| coliveira wrote:
| INRIA is very popular in the CS community, I wonder how you've
| never heard of their work.
| aaronblohowiak wrote:
| OCaml gets a lot of love here from time to time..
| aunetx wrote:
| Actually I was not even aware that they created ocaml nor
| scilab :/ so I seriously consider visiting this place again
| in a near future
| pjmlp wrote:
| Alongside Smalltalk, INRIA is also a major contributor to
| Pharo and Squeak, which descend both from the original
| Smalltalk-80 image.
| testcross wrote:
| The author explains what were the challenging bits in this thread
| (in french):
| https://twitter.com/DMerigoux/status/1314531302079688709
| agumonkey wrote:
| and his blog https://blog.merigoux.ovh/en/2019/12/20/taxes-
| formal-proofs....
| sushshshsh wrote:
| It's rare that I (an American) get to help out others by
| translating something, so I will post my translation here.
|
| "Four years after the first publication by DGFIP, I have the
| pleasure of announcing that the source code permitting the
| calculation of taxes on revenue is finally reusable
| (recompilable by others)!
|
| To use this algorithm in your application, follow this link...
|
| It took us 1.5 years (with my coauthor Raphael Monat) to
| identify that which was missing in the published code in order
| for it to be reusable, and to fix this situation.
|
| More or less, thanks to our project Mlang, a person can
| simulate IR's calculations without needing to interface with
| DGFIP.
|
| The difficulty came from a constraint from DGFIP, who did not
| want us to publish (for security reasons) a part of the code
| that corresponds to a mechanism that handles "multiple
| liquidations". Raphael and I recreated this unpublished part in
| a new DSL.
|
| DGFIP equally didnt want to publish their internal test games
| (cases). We had proceeded therefore with the creation of a
| suite of random test cases, separate from the non published
| ones, to finally be able to reproduce the validation of Mlang
| outside of DGFIP."
| jcranmer wrote:
| The last four posts in the Twitter thread:
|
| "A little less than a year after the publication of [blog
| post], we have therefore found a compromise letting us to
| respect both the obligation to publish the source code and
| the security constraints of DGFiP.
|
| In letting us publish the code on their site and accessing
| confidentially the source code they didn't want published,
| the DGFiP let us find alternative solutions that made the
| publication of the source code concrete and operational.
|
| This compromise lets both parties come out on top, unlike
| what happened with the source code of CNAF [link] where the
| administration simply argued a too-important difficulty and
| indefinitely postponed [1] it.
|
| Letting those who ask for the source code to see it after a
| NDA therefore appears to be a possible solution when the
| publication is delicate for technical reasons. Could this
| path be useful for the report of @ebothorel?"
|
| [Note: translation here is somewhat more geared towards a
| natural English translation than a literal French
| translation.]
|
| [1] "repouss[er] [...] aux calendes grecques" appears to be
| an idiom that's not in my dictionaries, but from context
| appears to mean "indefinitely postponed"
| pygy_ wrote:
| The _calendes_ were a Roman holiday IIRC. Greek ones simply
| don't exist...
| dakdak wrote:
| The calends [0] are the first day of every month in the
| Roman calendar. As the Ancient Greek calendar does not
| feature calends, postponing something to the Greek calends
| means postponing something to a later, unknown and unlikely
| to happen date.
|
| [0] https://en.wikipedia.org/wiki/Calends
| emilecantin wrote:
| Native French speaker here (Quebecois). Minor nitpick: Your
| translation of "jeux de tests" to "test games" is incorrect.
|
| The word "jeu" can indeed mean "game", but it can also mean a
| group of things. A better translation would be "test suites",
| "test sets" or similar.
| sushshshsh wrote:
| Thank you for your help! I did it totally on the fly
| without a dictionary and I enjoyed learning this word from
| you :)
| ficklepickle wrote:
| Bastille, tabernacle!
| ftomassetti wrote:
| You may be interested in what the Dutch Tax & Custom Agency is
| doing: they built a DSL to express tax calculations. Here you can
| find the case study:
| https://resources.jetbrains.com/storage/products/mps/docs/MP...
|
| Personally I work in the Language Engineering area and it seems
| obvious that you want tax lawyers and accountants to interpret
| the tax code and translate it into "code". Is just that you also
| want "code" to be obvious for them and support by proper tooling,
| which catch all inconsistencies.
|
| I would also love to interview the author of this and the work
| for mon-entreprise. While I understand French, I also have these
| interviews in English to reach more people
| dakdak wrote:
| There's a much broader project that can compute most taxes and
| benefits for France (and a few other countries) :
| https://github.com/openfisca/openfisca-france
|
| It would be quite interesting to check that both the French IRS
| implementation of the tax & benefit laws and the free software
| community (though most devs of the project were employed by the
| French admnistration) implementation of the tax and benefit laws
| actually output the same results.
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(page generated 2020-10-09 23:00 UTC)