DevoirDire by Jason

DevoirDire is a tool for authoring, checking, and managing formal logic documents, reducing ambiguity wherever rules, obligations and requirements must be stated precisely: law and policy, contracts, standards and specifications, or logic coursework.

Author formulas using predicate logic, quantifiers, equality, and deontic (Obligation/Permission/Prohibition) and temporal (Always/Eventually/Until) operators, built up node-by-node with a guided formula builder - no need to hand-write JSON or learn a text syntax.

Check your document three ways:

• Consistency: are these formulae simultaneously satisfiable?
• Validity: does a chosen conclusion follow from the rest?
• Soundness: is that argument valid and backed by a bundled fact store, or an external one you connect?

Deontic and temporal reasoning is opt-in per check, evaluated over a configurable, bounded set of possible worlds - every hedge and limitation is disclosed plainly in the results, never glossed over.

Manage documents locally: import, export, create, edit, restructure, and save dated revisions, all stored on your device. Nothing leaves your device unless you turn on one of two optional features, both off by default: shared editing or an external fact source.

Edit together (optional): host a document and invite others over a direct browser-to-browser link, with no server in between. Everyone confirms a safety number first, you choose who may edit, and every change is recorded as a revision.

Teaching mode poses auto-graded exercises for students to judge or build formula answers against, using the same checking engine as the main editor. After the last listed exercise it keeps posing fresh generated problems, with progress kept per type.

Keyboard and controller: everything is reachable with the keyboard, and single-key shortcuts for Teaching, the Documents list and the editor can be rebound or turned off (press ? to list them). Game controller support is optional, off until you switch it on in Preferences, and so far tried only with a simulated pad.

Available in English (Canadian), French (Canadian), German, Italian, and Japanese.