Logical English

Logical English, LE, is a controlled form of natural language that can be used for programming and knowledge representation.

It can also be regarded as syntactic sugar for Prolog, even though there is no exact match between existing Prolog implementations and LE. We are still searching for the best and more natural expressions for some critical concepts in knowledge representations, such as types, functions and composite terms in general.

For a general Introduction to Logical English, LE, (in PDF): Handbook.

Also, you can watch this video introducing Logical English.

For a more formal description of LE: le_syntax.md

For more about Logical English visit the testing site at LogicalContracts.com and the paper "Logical English for Legal Applications"

Software shared "as is", no warranties nor support whatsoever.

Licensing and copyright

All software in this directory is licensed as per Apache License 2.0 (https://www.apache.org/licenses/LICENSE-2.0) except where noted.

Initial copyright holders by country: LodgeIT (AU), AORA Law (UK), Bob Kowalski (UK), Miguel Calejo (PT), Jacinto Dávila (VE)

Special thanks to: Andrew Noble, Chris Mennell and Bruce Mennell

Tools for Writers of Logical English

LE EDITOR mode extension for Visual Studio Editor

We are happy to announce the new LE editor mode for the Visual Studio Code Editor, VSC, developed by Nikolai Merritt, as his MSc project at Imperial College. The whole code is here:

https://github.com/nikolaimerritt/LogicalEnglish

But the VSC extension can be obtained directly from within VSC. As the author explains: "Installing the extension is now very simple. Having installed Visual Studio Code, from the 'extensions' icon on the left bar, and search for "logical-english-vscode". (The extension comes up if you search for "logical english" or similar, but gets buried under lots of less new extensions.) It can also be found here https://marketplace.visualstudio.com/items?itemName=NikolaiMerritt.logical-english-vscode"

We want to encourage our friends to test it and, if you are so kind, report the experiences to us.

LE GUI extension to access a SWISH LE Server from Visual Studio Editor

This extension le-ui provides a user interface within the Visual Studio Editor, VSC, to translate LE documents and queries into Prolog code that it is executed on a SWISH server (defined in VSC settings). The interaction occurs through a "webview" that is displayed as a collapsible tab in the Explorer view of Visual Studio. It could also be displayed as a side tab in the editor view, using a right-click, contextual-menu option. Follow the link above for details.

Courseware

Work in progress: Visit this collection of self-teaching content on Logical English.

History of Development

TaxLog and LPS

Taxlog was the first implementation of purpose-specific, syntactic sugar for Prolog, under the umbrella of Logical English. Taxlog is still one fo the intented target for LE. However, the current implementation is not being maintained. For more about TaxLog see the TaxLog.md file.

There was also a preliminary experiment in the search for Logical English, but not with Prolog as target, but for LPS. That translator is still functional and can be referred as and tested here:

Dávila, J.: Rock-Paper-Scissors https://demo.logicalcontracts.com/p/rps-gets.pl (2017).

Projects using LE

Accziom.com

Introduction and list of resources at Advent of Logical English​​

University of Bologna

The University of Bologna has actively supported the development of LE, in pursue of the following stages and objectives of development:

Stage 1

1. Test the VSC editor mode and language server for LE and test its integration with SWISH. We adapted VSC so that this standalone server can interact with a SWISH server running the LE parser, via a JS API, to post, query and publish LE documents on the SWISH server.

Stage 2

1. Migrate the current implementation of LE to a WebAssembly Platform
2. Further explore and enhance its treatment of common nouns as types. Verify its application to legal concepts.
3. Refactor the error reporting system with feedback from users.
4. Complete the integration of LE with sCASP, including the integration with its explanations.
5. Fix bugs and answer issues in this repository.
6. Examine extensions to capture deontic reasoning and conflicts of legal rules.

Development RoadMap

1. TESTING NOW Improve the error detection system for better pinpointing of error location and cause.
2. TESTING NOW a. Store LE translation as a prolog or a s(CASP) file to be injected into SWISH storage (to appear in the SWISH file list).
3. Add a facility to name rules, initially to refer to them in the explainer, but eventually to incorporate naming of rules with rule priorities, to deal with hierarchies of rules and exceptions. Note that the resulting implementation of defeasibility can be accomplished either by means of a meta-interpreter, or by compiling rule priorities into lower-level Prolog rules with explicit negative conditions.
4. TESTING NOW Add a facility for naming and combining knowledge bases, with a view to obtaining some of the functionality of object-oriented systems, including inheritance and overriding.
5. TESTING NOW b. Develop an editor for LE with syntax and semantic highlighting, and error detection, as a separate editor project, preferably on JS Codemirror, using simple pengine calls to a SWISH server to assist the editing, and convert to different formats.
6. c. AFTER (b) is done, add .le as a valid SWISH file type.
7. Add a treatment of common nouns as types.
8. Update older examples into the new syntax extensions.

Support RoadMap

1. Opening the discussion forum
2. Update the LE handbook with the latest syntax extensions.
3. Add more examples (both to the report and the handbook).

Older Examples under review

1. 1_net_asset_value_test Determine if a given entity satisfies the maximum net value test for Capital Gain Test, CGT, assets.
2. 2_r_and_d_tax_reliefs Determine if a project qualifies for the EIS.
3. 3_rollover_2 Decide whether the small business restructure rollover applies to an event.
4. 4_affiliates Determine if a given entity is affiliate of another (also given).
5. 5_tax_reliefs Determine if an electronic transaction is exempt from SDRT.
6. 6_statutory_residence Determine if a person is a UK resident for tax purposes.
7. 7_loan_agreement The Loan Agreement (and many variations with and without the Event Calculus)
8. 014_escrow A blockchain-like escrow agreement.
9. cittadinanza_ita Cittadinanza Italiana (Italian Citizenship, many versions and translation into sCASP).
10. 010_isda_agreement The ISDA Agreement (Many versions including isda-permission-corrected)
11. oecd_test_for_inclusion OECD example with an included document.
12. criminal_justice Criminal justice example.
13. subsets Subsets example in many languages and into Prolog and sCASP.
14. permitted that Example with metavariables.
15. minicontractv2 A proposed format for an electronic contract.

Release Notes

• [2024-08-08] Previous version 328c4b7d1cb5e146a3e5175b4537d30a3f69c7e6
  • Static Prolog LE server without SWISH
    • From https://github.com/LogicalContracts/LogicalEnglish/tree/main/clientExample/my-app
    • swipl simple_server.pl --port=3052 --staticdir='./build'
    • with static files being produced by: npm run build
    • from models in: https://github.com/LogicalContracts/LogicalEnglish/tree/main/clientExample/my-app/public
    • runs from URL: http://localhost:3052/static/simple_client.html
• [2023-06-12] Previous version 8db435763dad4afbf1cf5f8c46c16d3f53f7255c
  • New handling of mathematical expressions.
  • New translation of is in English as unification "=" in Prolog.
  • New translation of = in English as "is" assignment in Prolog.
• [2023-04-09] Previous version 37dadce4c7916ed47c79c770ac575330d60f8f94
  • New VSC extension LE GUI (with new JS API and collapsible explanations)
  • Standalone LE
• [2022-05-12] Beta testing. Previous version 97abce7d4398f05c1f165e4a411a982b16f358bd
  • Activates #abducible to handle unknown information with sCASP in LE.
• [2022-05-05] Beta testing. Previous version: d405af4da4fbeb170cd1cb1be333ff66c65a8d98
  • Merging branch logical_languages with the latest extensions of LE syntax for sources in Italian, French and Spanish and targeting sCASP beside Prolog. Also, inclusion of other documents.
• [2021-11-23] Updating the roadmap. Previous version: c4d67e9e0dbc54356473b284c9b72725c6504673
• [2021-11-08] Beta testing.
  • Adding extract_variable_template/7 as specific predicates for templates. Fixing bug in output of answers with dates.
• [2021-11-07] Beta testing. Previous version: 92d90631853812384463c1cb2c2f1607e0a3fd64
  • Adding the command show types, to display the list of type identifier available in predefined templates and in the current document.
  • Templates are therefore formally used to capture type information for variables. Any combination of words between the asteriks identifies a type, except for ordinal.
  • Added is_type/1 (dynamic predicate) and pre_is_type/1 (for predefined templates) to record that information in memory.
  • Correcting the use of dictionary/3 in le_output
• [2021-11-02] Alfa testing. Last version: eb0039077d068dd718ef47fd81af95554faeaef3
  • Updates to documentation, README.md, licensing and querying machinery.
• [2022-02-06] Update of the server. Last version: 6b89eb9e75066d1074769005e9675ffa2b4d7470
  • Explanation facilities improved and operational via answer(query, with(scenario), le(E), R)
  • Fixed multi-level indentation.
  • Parsing speed improved.
  • Translation from LE to s(CASP) via show(scasp, with(query, scenario)).
  • Changes for error reporting inside conditions.
  • New examples.