# PARTY

Identifies the legal party (person or entity) who has an obligation, permission, or prohibition in a regulative rule.

## Syntax

```l4
PARTY partyName
PARTY partyName MUST ...
PARTY partyName MAY ...
PARTY partyName SHANT ...
```

## Purpose

PARTY is the starting point for regulative rules, specifying WHO is subject to the rule. It introduces:

- Obligations (MUST)
- Permissions (MAY)
- Prohibitions (SHANT)

## Examples

**Example file:** 

```l4-file
-- PARTY keyword examples (regulative rules for legal contracts)
--
-- This file demonstrates L4's regulative features for legal drafting,
-- showing how to express obligations, permissions, and prohibitions that
-- are commonly found in contracts, legislation, and regulations.

-- Type Declarations

DECLARE `Legal Entity` IS ONE OF
  `The Borrower`
  `The Lender`
  `The Seller`
  `The Buyer`
  `The Employee`
  `The Employer`
  `The Tenant`
  `The Landlord`

DECLARE `Contract Action` IS ONE OF
  `make payment` HAS amount IS A NUMBER
  `deliver goods` HAS description IS A STRING
  `provide services`
  `sign document` HAS `document name` IS A STRING
  `disclose confidential information`
  `vacate premises`
  `pay damages` HAS amount IS A NUMBER

-- Basic Obligation (MUST)

-- Simple payment obligation with a deadline
-- The Borrower must make a payment within 30 days
`payment obligation` MEANS
  PARTY `The Borrower`
  MUST `make payment` 5000
  WITHIN 30

-- Permission (MAY)

-- Early termination right
-- The Tenant may vacate the premises early without penalty
`early termination right` MEANS
  PARTY `The Tenant`
  MAY `vacate premises`
  WITHIN 60

-- Prohibition (SHANT)

-- Non-disclosure obligation (confidentiality clause)
-- The Employee shall not disclose confidential information for 2 years
`confidentiality obligation` MEANS
  PARTY `The Employee`
  SHANT `disclose confidential information`
  WITHIN 730  -- 2 years in days

-- Alternative syntax: MUST NOT
-- Same prohibition expressed differently
`confidentiality obligation alternative` MEANS
  PARTY `The Employee`
  MUST NOT `disclose confidential information`
  WITHIN 730

-- With Consequences (HENCE/LEST)

-- Payment with grace period and penalty
-- If The Borrower pays on time, the contract is fulfilled.
-- If not, they must pay with a penalty within a grace period.
`payment with penalty clause` MEANS
  PARTY `The Borrower`
  MUST `make payment` 1000
  WITHIN 30
  HENCE FULFILLED
  LEST (
    PARTY `The Borrower`
    MUST `make payment` 1100  -- 10% penalty
    WITHIN 45  -- 15-day grace period
    LEST BREACH
  )

-- Chained Obligations

-- Purchase and delivery contract
-- The Buyer pays, then The Seller must deliver goods
`purchase and delivery contract` MEANS
  PARTY `The Buyer`
  MUST `make payment` 5000
  WITHIN 7
  HENCE
    PARTY `The Seller`
    MUST `deliver goods` "electronic equipment"
    WITHIN 14
    HENCE FULFILLED

-- Service contract with multiple steps
-- Sign document, then provide services, then receive payment
`service agreement` MEANS
  PARTY `The Employee`
  MUST `sign document` "employment contract"
  WITHIN 7
  HENCE
    PARTY `The Employee`
    MUST `provide services`
    WITHIN 90
    HENCE
      PARTY `The Employer`
      MUST `make payment` 3000
      WITHIN 7
      HENCE FULFILLED

-- Testing with #TRACE

-- Test 1: Payment obligation fulfilled on time
#TRACE `payment obligation` AT 0 WITH
  PARTY `The Borrower` DOES `make payment` 5000 AT 20

-- Test 2: Payment obligation breached (no payment)
#TRACE `payment obligation` AT 0 WITH

-- Test 3: Early termination right exercised
#TRACE `early termination right` AT 0 WITH
  PARTY `The Tenant` DOES `vacate premises` AT 30

-- Test 4: Confidentiality maintained (no breach)
#TRACE `confidentiality obligation` AT 0 WITH

-- Test 5: Payment with penalty - paid in grace period
#TRACE `payment with penalty clause` AT 0 WITH
  PARTY `The Borrower` DOES `make payment` 1100 AT 40

-- Test 6: Purchase and delivery - happy path
#TRACE `purchase and delivery contract` AT 0 WITH
  PARTY `The Buyer` DOES `make payment` 5000 AT 5
  PARTY `The Seller` DOES `deliver goods` "electronic equipment" AT 15

-- Test 7: Service agreement - complete workflow
#TRACE `service agreement` AT 0 WITH
  PARTY `The Employee` DOES `sign document` "employment contract" AT 3
  PARTY `The Employee` DOES `provide services` AT 50
  PARTY `The Employer` DOES `make payment` 3000 AT 100
```



### Basic Obligation

```l4
DECLARE Person IS ONE OF Alice, Bob

myRule MEANS
  PARTY Alice
  MUST DO sing
  WITHIN 30
```

### Permission

```l4
permissionRule MEANS
  PARTY Bob
  MAY DO dance
  WITHIN 60
```

### Prohibition

```l4
prohibitionRule MEANS
  PARTY Alice
  SHANT smoke
  WITHIN 30
```

### With Consequences

```l4
ruleWithConsequence MEANS
  PARTY Alice
  MUST DO pay
  WITHIN 30
  LEST PARTY Bob MAY DO sue WITHIN 60
```

## Regulative Rule Structure

A complete regulative rule typically includes:

```l4
ruleName MEANS
  PARTY who          -- The party subject to the rule
  MUST/MAY/SHANT     -- The deontic modality
  DO action          -- What action is regulated
  WITHIN deadline    -- Time constraint
  HENCE consequent   -- What follows if rule is followed
  LEST alternative   -- What follows if rule is violated
```

## Related Keywords

- **[MUST](/l4/reference/regulative/MUST.md)** - Obligation
- **[MAY](/l4/reference/regulative/MAY.md)** - Permission
- **[SHANT](/l4/reference/regulative/SHANT.md)** - Prohibition
- **[REGULATIVE](/l4/reference/regulative.md)** - Full regulative rule reference

## See Also

- **[Regulative Rules](/l4/concepts/legal-modeling/regulative-rules.md)** - Modeling obligations