-- Parse_CspCASL_Process.hs

--

-- WIP parser for CSP-CASL processes.

--

-- Maintainer: Andy Gimblett <a.m.gimblett@swan.ac.uk>

--

-- Changelog:

-- 2006.10.13.1528 AMG v1.0

-- Split from Parse_CspCASL.hs

{- Parse_CspCASL_Process.hs -- WIP parser for CSP-CASL processes.

-}

module CspCASL.Parse_CspCASL_Process (

csp_casl_process,

process_name,

recProcess,

recProcessDefn,

) where

import Text.ParserCombinators.Parsec (sepBy, try, (<|>), chainl1)

import qualified CASL.Formula

import CASL.AS_Basic_CASL (VAR)

import Common.AnnoState (AParser, asKey)

import Common.Id (equalS)

import Common.Keywords (colonS, ifS, inS, letS, thenS, elseS)

import Common.Lexer (semiT)

import Common.Token (colonST, parseId, sortId, varId)

import CspCASL.AS_CspCASL_Process

import CspCASL.CspCASL_Keywords

-- Processes

csp_casl_process :: AParser st PROCESS

csp_casl_process = do p <- process

return p

-- Recursive processes

recProcess :: AParser st REC_PROCESS

recProcess = do asKey letS

rds <- recProcessDefn `sepBy` semiT

(try semiT)

asKey inS

p <- process

return (RecProcessConstructor rds p)

-- Recursive process definitions

recProcessDefn :: AParser st REC_PROCESS_DEFN

recProcessDefn = try (do pn <- process_name

asKey parens_openS

(v, es) <- varEventSet

asKey parens_closeS

asKey equalS

p <- process

return (RecProcessVar pn v es p)

)

<|> (do pn <- process_name

asKey equalS

p <- process

return (RecProcessSimple pn p)

)

varEventSet :: AParser st (VAR, EVENT_SET)

varEventSet = do v <- var

asKey colonS

es <- event_set

return (v, es)

-- Process names

process_name :: AParser st PROCESS_NAME

process_name = do p_name <- parseId csp_casl_keywords

return p_name

-- PROCESS => PARALLEL_PROCESS

process :: AParser st PROCESS

process = try conditional_process

<|> parallel_process

conditional_process :: AParser st PROCESS

conditional_process = do asKey ifS

f <- formula

asKey thenS

p <- process

asKey elseS

q <- process

return (ConditionalProcess f p q)

-- PARALLEL_PROCESS => CHOICE_PROCESS

-- | PARALLEL_PROCESS || CHOICE_PROCESS

-- | PARALLEL_PROCESS ||| CHOICE_PROCESS

parallel_process :: AParser st PROCESS

parallel_process = complex_parallel `chainl1` parallel_operator

parallel_operator :: AParser st (PROCESS -> PROCESS -> PROCESS)

parallel_operator = try (do asKey interleavingS

return interleaving

)

<|>

try (do asKey synchronousS

return synchronous

)

synchronous :: PROCESS -> PROCESS -> PROCESS

synchronous left right = SynchronousParallel left right

interleaving :: PROCESS -> PROCESS -> PROCESS

interleaving left right = Interleaving left right

complex_parallel :: AParser st PROCESS

complex_parallel = try (do p <- choice_process

asKey general_parallel_openS

es <- event_set

asKey general_parallel_closeS

q <- parallel_process

return (GeneralisedParallel p es q)

)

<|>

try (do p <- choice_process

asKey alpha_parallel_openS

es_p <- event_set

asKey alpha_parallel_sepS

es_q <- event_set

asKey alpha_parallel_closeS

q <- parallel_process

return (AlphabetisedParallel p es_p es_q q)

)

<|>

choice_process

-- CHOICE_PROCESS => PREFIX_SEQUENCE_PROCESS

-- | CHOICE_PROCESS [] PREFIX_SEQUENCE_PROCESS

-- | CHOICE_PROCESS |~| PREFIX_SEQUENCE_PROCESS

choice_process :: AParser st PROCESS

choice_process = sequence_process `chainl1` choice_operator

choice_operator :: AParser st (PROCESS -> PROCESS -> PROCESS)

choice_operator = try (do asKey external_choiceS

return external

)

<|>

try (do asKey internal_choiceS

return internal

)

external :: PROCESS -> PROCESS -> PROCESS

external left right = ExternalChoice left right

internal :: PROCESS -> PROCESS -> PROCESS

internal left right = InternalChoice left right

-- SEQUENCE_PROCESS => PREFIX_PROCESS

-- | SEQUENCE_PROCESS ; PREFIX_PROCESS

sequence_process :: AParser st PROCESS

sequence_process = prefix_process `chainl1` sequence_operator

sequence_operator :: AParser st (PROCESS -> PROCESS -> PROCESS)

sequence_operator = try (do asKey semicolonS

return sequencing

)

sequencing :: PROCESS -> PROCESS -> PROCESS

sequencing left right = Sequential left right

-- PREFIX_PROCESS => [] VAR: EVENT-SET -> HIDING_RENAMING_PROCESS

-- | EVENT -> HIDING_RENAMING_PROCESS

-- | HIDING_RENAMING_PROCESS

prefix_process :: AParser st PROCESS

prefix_process = try (do asKey external_prefixS

v <- var

colonST

es <- event_set

asKey prefixS

p <- prefix_process

return (ExternalPrefixProcess v es p)

)

<|>

try (do asKey internal_prefixS

v <- var

colonST

es <- event_set

asKey prefixS

p <- prefix_process

return (InternalPrefixProcess v es p)

)

<|>

try (do e <- event

asKey prefixS

p <- prefix_process

return (PrefixProcess e p)

)

<|>

hiding_renaming_process

-- HIDING_RENAMING_PROCESS => PRIMTIVE_PROCESS HIDING_RENAMING_W

--

-- HIDING_RENAMING_W => \ EVENT-SET

-- | [[CSP-RENAMING]]

-- | epsilon

hiding_renaming_process :: AParser st PROCESS

hiding_renaming_process = do pl <- parenthesised_or_primitive_process

p <- (hiding_renaming_w pl)

return p

hiding_renaming_w :: PROCESS -> AParser st PROCESS

hiding_renaming_w pl = try (hiding_renaming_z pl) <|> (return pl)

hiding_renaming_z :: PROCESS -> AParser st PROCESS

hiding_renaming_z pl = do asKey hidingS

es <- event_set

p <- (hiding_renaming_w (Hiding pl es))

return p

<|>

do asKey renaming_openS

rn <- primitive_renaming

asKey renaming_closeS

p <- (hiding_renaming_w (Renaming pl rn))

return p

-- PARENTHESISED_OR_PRIMITIVE_PROCESS => (PROCESS)

-- | RUN EventSet

-- | Chaos EventSet

-- | div

-- | SKIP

-- | STOP

parenthesised_or_primitive_process :: AParser st PROCESS

parenthesised_or_primitive_process = do asKey parens_openS

p <- process

asKey parens_closeS

return p

<|>

primitive_process

primitive_process :: AParser st PROCESS

primitive_process = try run <|> try chaos <|> try divergence <|> try skip <|> stop

-- Hard-coded primitive processes.

run :: AParser st PROCESS

run = do asKey runS

es <- event_set

return (Run es)

chaos :: AParser st PROCESS

chaos = do asKey chaosS

es <- event_set

return (Chaos es)

-- Can't just call this "div" because that clashes with div from the

-- Prelude.

divergence :: AParser st PROCESS

divergence = do asKey divS

return Div

skip :: AParser st PROCESS

skip = do asKey skipS

return Skip

stop :: AParser st PROCESS

stop = do asKey stopS

return Stop

-- Event sets are just CASL sorts...

event_set :: AParser st EVENT_SET

event_set = do sort_id <- sortId csp_casl_keywords

return (EventSet sort_id)

-- Events are CASL terms, but will (later) include stuff to with

-- channels.

event :: AParser st EVENT

event = do t <- CASL.Formula.term csp_casl_keywords

return (Event t)

-- Formulas are CASL formulas. We make our own wrapper around them

-- however.

formula :: AParser st CSP_FORMULA

formula = do f <- CASL.Formula.formula csp_casl_keywords

return (Formula f)

-- Primitive renaming is done using an operator name or a predicate

-- name. They're both Ids. Separation between operator or predicate

-- (or some other non-applicable Id) must be a static analysis

-- problem.

primitive_renaming :: AParser st PRIMITIVE_RENAMING

primitive_renaming = do { rid <- parseId csp_casl_keywords

; return rid

}

-- Variables come from CASL/Hets.

var :: AParser st VAR

var = varId csp_casl_keywords