Underscores in local variable names

[frans-bergman]

Most modern programming languages allow using underscores in variable names. Figure 1 in this paper (https://arxiv.org/pdf/2201.06312.pdf) also suggests that underscores should be allowed in variable names. However, when defining a local variable with an underscore in its name, parsing fails.

Can support for underscores in variable names (and other identifiers) be added?

Example of non-working recipe script (cLink has been replaced with c_link):

channels: c, empty, g1, g2,vmm1,vmm2,vmm3,t
enum rolevals {clnt, vm, mgr}
enum msgvals {reserve, request, release, buy, connect, full,complete}
message-structure: MSG : msgvals, LNK : channel
communication-variables: cv : rolevals
guard g(r : rolevals, c : channel, m : channel) := (channel == *) && (@cv == r) | (channel == c) && (@cv == mgr) | (channel == m) ;

agent Client
    local: role : rolevals, c_link : channel, mLink : channel, tLink : channel
    init: c_link == c && mLink == empty && tLink == t && role==clnt
    relabel:
        cv <- role
    receive-guard: (channel == *) | (channel == c_link) | (channel == tLink)

    repeat: (
            (sReserve: <c_link==c> *! g(role,c_link,mLink)(MSG := reserve)[c_link := c]
            +
            rReserve: < c_link==c && MSG == reserve> *? [c_link := empty]
            )
            ;

            (sRequest: <c_link!=empty> c_link! g(role,c_link,mLink)(MSG := request)[c_link := c];
             rConnect: <mLink==empty && MSG == connect> c_link? [mLink := LNK];
             sRelease: <TRUE> *! g(role,c_link,mLink)(MSG := release)[c_link := empty];
             sBuy: <mLink!=empty> mLink! g(role,c_link,mLink)(MSG := buy)[mLink := empty];
             (
                sSolve: <TRUE> tLink! g(role,c_link,tLink)(MSG := complete)[]
               +
                <MSG == complete> tLink? []
             )

            +
             rRelease: <c_link==empty && MSG == release> *? [c_link := c]
            )
            )

agent Manager
    local: role : rolevals, c_link : channel, sLink : channel, hLink : channel
    init: hLink == g1 && sLink == g2 && c_link == c && role==mgr
    relabel:
        cv <- role
    receive-guard: (channel == *) | (channel == c_link) | (channel == hLink)

    repeat: (
            rRequest: <MSG == request> c_link? [];
            sForward: <TRUE> hLink! (TRUE)(MSG := request)[];
            (
             rep (rFull: <MSG == full> hLink? [];
                  sRequest: <TRUE> sLink! (TRUE)(MSG := request)[]
                 )
             +
             rConnect: <MSG == connect> c_link? []
            )
            )

agent Machine
    local: gLink : channel, pLink : channel, c_link : channel, asgn : bool
    init: !asgn && (c_link == empty)
    relabel:
        cv <- vm
    receive-guard: (channel == *) | (channel == gLink)  | (channel == pLink) | (channel == c_link)

    repeat: (
           rForward: <c_link==empty && MSG == request> gLink? [c_link:= c];
            (
             sConnect: <c_link==c && !asgn> c_link! (TRUE)(MSG := connect, LNK := pLink)[c_link:= empty, asgn:= TRUE]
             +
             sFull: <c_link==c && asgn> gLink! (TRUE)(MSG := full)[c_link:= empty, asgn:= TRUE]
             +
             rConnect: <c_link==c && MSG == connect> c_link? [c_link:= empty]


             +
             rFull: <c_link==c && asgn && MSG == full> gLink? [c_link:= empty, asgn:= TRUE]
            )
            +
            rBuy: <MSG == buy> pLink? []
            )

system = Client(client1,TRUE) | Client(client2,TRUE) | Client(client3,TRUE) |  Manager(manager,TRUE) | Machine(machine1,gLink==g1 && pLink==vmm1) | Machine(machine2,gLink==g1 && pLink==vmm2) | Machine(machine3,gLink==g2 && pLink==vmm3)

SPEC G ( (F(client1-mLink!=empty) & F (client2-mLink!=empty) & F (client3-mLink!=empty)) -> F (client1-sSolve | client2-sSolve | client3-sSolve));

[shaunazzopardi]

Good idea, will implement this change soon.