Rule Catalogue

A proposal, not a decision. Every entity and relationship below is open to challenge; the open decisions are listed at the end.

Version 0.1, 25 September 2026. The rules Mevo Hagalil applies to its timetable, and the general, parameterised rule types they instantiate, so that a different school can pick from the same catalogue and configure it for itself.

Overview

A school's timetable rules are of two kinds. Structure describes the school: its week, classes, staff, rooms and curriculum. Rules restrict or score how lessons may be placed. In this product every rule is a row with a type, parameters, a scope, a hard-or-soft flag and a weight, never a line of code. Mevo Hagalil's 22 rows instantiate 14 general types. The catalogue below lists those types with their parameters, the Mevo Hagalil settings that use each one, and the further types the XHSTT standard and the market research suggest a general product needs.

Summary

• Mevo Hagalil applies 22 rules: 4 structural facts about the week and staffing that are inputs rather than choices, 11 hard rules, and 7 soft rules with weights.
• They instantiate 14 general rule types in six families: clashes and availability, fixed events, a teacher's day shape, a class's day shape, subject placement, and rooms.
• Every type has parameters (which staff, which classes, which periods, how many, exact or minimum) and a scope, so the same type serves "three lessons a day" for one school and "at most six" for another.
• The catalogue is open: 9 further types from XHSTT and the requirements of other school kinds are listed as planned, with their parameters, so they can be added without touching the engine's structure.

Bottom line

Keep rules as data rows of catalogued types. For a new school the onboarding flow becomes: describe the structure, tick the rule types that apply, fill in the parameters, decide hard or soft and weight. Mevo Hagalil is the first configuration of the catalogue, not a special case in code.

Detailed explanation

1. The rules Mevo Hagalil applies

Grouped by family. Source is the requirement or fact ID; Vegman's answers refined most of them.

Structure (inputs, not choices)

Hard rules

Soft rules (weight in brackets)

2. From school rules to general rule types

Each row above is an instance of a general type. The type fixes what is measured; the parameters fix for whom, where and how much; the flag and weight fix how strictly. A rule row therefore looks like:

type:      teacher-lessons-per-day
scope:     staff = [all teachers] or a list, days = all or a list
params:    min = 3, max = 6
hard:      false, weight: 20
implements: (this school's own reference, e.g. R-xx)

The example in the question, "a teacher teaches three lessons on a given day", is the type teacher-lessons-per-day with min = max = 3 for that teacher and that day; another school sets max = 6 for everyone. Same type, different rows.

3. The general catalogue

Types marked live are implemented in the engine and the prototype today. Types marked planned are specified here so the catalogue is complete; their parameters are chosen to match XHSTT so a benchmark instance can be imported.

Family A: clashes and availability

Family B: the teacher's day

Family C: the class's day

Family D: rooms

Family E: students and groups (needed for junior-high and high-school variants, not for Mevo Hagalil)

Family F: staff contracts (Israeli reforms)

4. How a school configures the catalogue

1. Describe the structure: week grid with breaks, grades and classes, staff with contracts and availability, rooms with owners, curriculum per grade.
2. Open the rule catalogue. Every type appears with a plain-language description and its parameters; the school ticks the ones that apply.
3. Fill in the parameters per row; add several rows of one type when different scopes need different values.
4. Mark each row hard or soft and give soft rows a weight. The prototype's rules page is already this screen for Mevo Hagalil's rows.
5. Score the current timetable against the rows before solving, to see which rules it already breaks; then solve.

5. Open decisions

• Whether teacher-lessons-per-day, class-lessons-per-day and resource-busy-limit are one type with a resource-kind parameter or three types with friendlier names. The engine can implement one; the catalogue can show three.
• Weight scales: a shared scale (1 to 100) with named anchors (mild, strong, near-hard) so weights mean the same across schools.
• Localisation of rule names and descriptions: the catalogue carries Hebrew and English text per type, the same way the requirements do.

type:      teacher-lessons-per-day
scope:     staff = [all teachers] or a list, days = all or a list
params:    min = 3, max = 6
hard:      false, weight: 20
implements: (this school's own reference, e.g. R-xx)