{- |

Abstract syntax of CSP-CASL processes.

-}

module CspCASL.AS_CspCASL_Process (

EVENT(..),

EVENT_SET(..),

CSP_FORMULA(..),

PRIMITIVE_RENAMING,

PROCESS(..),

PROCESS_DEFN(..),

PROCESS_NAME,

REC_PROCESS(..),

REC_PROCESS_DEFN(..),

CHANNEL_DECL(..),

CHANNEL_ITEM(..),

CHANNEL_NAME,

) where

import CASL.AS_Basic_CASL (FORMULA, SORT, TERM, VAR, VAR_DECL)

import Common.Id (Id, SIMPLE_ID)

{- PROCESS-DEFN ::= PROCESS

| REC-PROCESS

| var/vars VAR-DECL; ...; VAR-DECL;/ . PROCESS

| var/vars VAR-DECL; ...; VAR-DECL;/ . REC-PROCESS

-}

data PROCESS_DEFN

= Process PROCESS

| RecProcess REC_PROCESS

| ProcessVars [VAR_DECL] PROCESS

| RecProcessVars [VAR_DECL] PROCESS

deriving (Show)

{- REC-PROCESS ::= let REC-PROCESS_DEFN; ...; REC-PROCESS-DEFN;/ in PROCESS

-}

data REC_PROCESS

= RecProcessConstructor [REC_PROCESS_DEFN] PROCESS

deriving (Show)

{- REC-PROCESS-DEFN ::= PROCESS-NAME = PROCESS

| PROCESS-NAME (VAR: EVENT-SET) = PROCESS

-}

data REC_PROCESS_DEFN

= RecProcessSimple PROCESS_NAME PROCESS

| RecProcessVar PROCESS_NAME VAR EVENT_SET PROCESS

deriving (Show)

-- |Events. These are CASL terms. The old CSP-CASL parser also

-- included "Send" and "Receive" forms (commented out below), which I

-- suspect will become important when we bring in channels.

data EVENT

= Event (TERM ())

-- Send CHANNEL_NAME (TERM ())

-- Receive CHANNEL_NAME VAR SORT

deriving (Show,Eq)

-- |Event sets. These are basically just CASL sorts.

data EVENT_SET

= EventSet SORT

deriving (Show,Eq)

-- |Formulas. These are basically just CASL formulas.

data CSP_FORMULA

= Formula (FORMULA ())

deriving (Show,Eq)

-- |CSP renamings. Just Ids, for operator names and predicate

-- names.

type PRIMITIVE_RENAMING = Id

{- PROCESS_NAME ::= SIMPLE-ID

-}

type PROCESS_NAME = Id

-- |CSP-CASL process expressions.

data PROCESS

-- | @Skip@ - Terminate immediately

= Skip

-- | @Stop@ - Do nothing

| Stop

-- | @div@ - Divergence

| Div

-- | @Run es@ - Accept any event in es, forever

| Run EVENT_SET

-- | @Chaos es@ - Accept\/refuse any event in es, forever

| Chaos EVENT_SET

-- | @es -> p@ - Prefix process

| PrefixProcess EVENT PROCESS

-- | @[] var : es -> p@ - Internal nondeterministic prefix choice

| InternalPrefixProcess VAR EVENT_SET PROCESS

-- | @|~| var : es -> p@ - External nondeterministic prefix choice

| ExternalPrefixProcess VAR EVENT_SET PROCESS

-- | @p ; q@ - Sequential process

| Sequential PROCESS PROCESS

-- | @p [] q@ - External choice

| ExternalChoice PROCESS PROCESS

-- | @p |~| q@ - Internal choice

| InternalChoice PROCESS PROCESS

-- | @p ||| q@ - Interleaving

| Interleaving PROCESS PROCESS

-- | @p || q @ - Synchronous parallel

| SynchronousParallel PROCESS PROCESS

-- | @p [| a |] q@ - Generalised parallel

| GeneralisedParallel PROCESS EVENT_SET PROCESS

-- | @p [ a || b ] q@ - Alphabetised parallel

| AlphabetisedParallel PROCESS EVENT_SET EVENT_SET PROCESS

-- | @p \\ es@ - Hiding

| Hiding PROCESS EVENT_SET

-- | @p [[r]]@ - Renaming

| Renaming PROCESS PRIMITIVE_RENAMING

-- | @if f then p else q@ - Conditional

| ConditionalProcess CSP_FORMULA PROCESS PROCESS

-- | CSPSeq [PROCESS]

deriving (Eq, Show)

-- We don't do anything with channels yet, but we need their

-- declaration to fit in with hets machinery, for now at least.

data CHANNEL_DECL = Channel_items [CHANNEL_ITEM]

deriving Show

data CHANNEL_ITEM = Channel_decl [CHANNEL_NAME] SORT

deriving Show

type CHANNEL_NAME = SIMPLE_ID