# LTL Plugin2.2 Input Syntax

The LTL plugin uses the following syntax, which is defined in BNF:

// BNF below is extended with {p} for zero or more and [p] for zero or one repetitions of p

// The mandatory MOP logic syntax

<LTL Name> ::= "ltl"

<LTL Syntax> ::= "true" | "false"

| <Event Name> // events are atomic propositions

| <Not> <LTL Syntax> // negation

| <LTL Syntax> "and" <LTL Syntax> // conjunction

| <LTL Syntax> "or" <LTL Syntax> // disjunction

| <LTL Syntax> "xor" <LTL Syntax> // XOR: eXclusive OR

| <LTL Syntax> "=>" <LTL Syntax> // implies

| <LTL Syntax> "<=>" <LTL Syntax> // if and only if

| "[]" <LTL Syntax> // always

| "<>" <LTL Syntax> // eventually

| "o" <LTL Syntax> // next

| <LTL Syntax> "U" <LTL Syntax> // until

| "[*]" <LTL Syntax> // always in the past

| "<*>" <LTL Syntax> // eventually in the past

| "(*)" <LTL Syntax> // previously

| <LTL Syntax> "S" <LTL Syntax> // since

<LTL State> ::= "violation"

### <LTL Name>

<LTL Name> instantiates <Logic Name> from the MOP Syntax. It denotes the LTL logic using the string "ltl".

### <LTL Syntax>

<LTL Syntax> instantiates <Logic Syntax> from the MOP Syntax.
<LTL Syntax> is based on constants and atomic propositions with boolean operators and
temporal operators. The different operators in decreasing order of precedence are
[]`,`
[*]`,`
<>`,`
<*>`,`
o`,`
(*)`,`
!`,`
not `>`
U `>`
S `>`
<And> `>`
<Xor> `>`
<Or>
`>` <Implies>
`>`<->.

The last eight operators from <LTL Syntax> are called *temporal* and have the following interpretation:

- []
`X`holds if`X`holds in all time points - <>
`X`holds if`X`holds in some future time point -
`X`U`Y`holds if`Y`holds in some future time point, and`X`has holds until`Y`holds (strict since) - o
`X`holds if`X`holds at the next time point - [*]
`X`holds if`X`holds in all past time points - <*>
`X`holds if`X`holds in some past time point -
`X`S`Y`holds if`Y`holds in some past time point, and since then`X`has held (strict since) - (*)
`X`holds if`X`holds at the previous time point

- []

### <LTL State>

<LTL State> instantiates <Logic State> from the MOP Syntax. In a LTL specification, <LTL State> can be either the special state validation or violation. validation corresponds to a situation wherein the trace satisfies the given formula, whereas violation occurs when the trace is not a prefix of any trace that satisfy the give formula.

### <Not>

The LTL plugin supports various kinds of not operators

### <And>

The LTL plugin supports various kinds of and operators

### <Or>

The LTL plugin supports various kinds of or operators

### <Xor>

The LTL plugin supports various kinds of xor operators

### <Implies>

The LTL plugin supports various kinds of implies operators

### Example

<mop>

<Client>Web</Client>

<Events>acquire request</Events>

<Property>

<Logic>ltl</Logic>

<Formula>[](acquire => (*) request)</Formula>

</Property>

<Categories>violation</Categories>

</mop>