# 
# RELAX NG Schema for PGIP, the Proof General Interface Protocol                   
# 
# Authors:  David Aspinall, LFCS, University of Edinburgh       
#           Christoph Lueth, University of Bremen       
#
# Version: $Id: pgip.rnc,v 1.1 2005/09/30 15:24:51 aspinall Exp $    
# 
# Status:   Prototype.
#
# For additional commentary, see accompanying commentary document available at
# http://proofgeneral.inf.ed.ac.uk/Kit/docs/commentary.pdf
#
# Advertised version: 2.0
# 
# Contents
# ========
#
#  0. Prelude
#  1. Top-level 
#  2. Component Control messages
#  3. Display Commands
#  4. Prover Configuration
#  5. Interface Configuration
#  6. Prover Control
#  7. Proof script markup and proof control
#

# ==============================================================================
# 0. Prelude
# ==============================================================================

include "pgml.rnc"                           # include PGML grammar

name_attr = attribute name { text }          # names are user-level textual identifiers
thyname_attr = attribute thyname { text }    # names for theories (special case of name)
thmname_attr = attribute thmname { text }    # names for theorems (special case of name)

datetime_attr = 
   attribute datetime { xsd:dateTime }       # CCYY-MM-DDHH:MM:SS plus timezone info
url_attr  = attribute url { xsd:anyURI }     # URLs  (often as "file:///localfilename.extn")
dir_attr  = attribute dir { text }           # Unix-style directory name (no final slash)

systemdata_attr  = 
            attribute systemdata { text }?   # system-specific data (useful for "stateless" RPC)


objname = string
termobjname = string                         # (User-level) object names, semi-colon terminated
objnames = string                            # A sequence of objnames

#termobjname  = xsd:string { pattern = "[^;]+;" }  # unfortunately these declarations don't 
#objnames = objname+                               #  work with the RNC->DTD tool trang


# ==============================================================================
# 1. Top-level Messages/documents
# ==============================================================================

start = pgip                                 # Single message
      | pgips                                # A log of messages between components
      | displayconfig                        # displayconfig as a standalone element
      | pgipconfig                           # pgipconfig as a standalone element

pgip = element pgip {                        #  A PGIP packet contains:
   pgip_attrs,                               #   - attributes with header information;
   (toprovermsg | todisplaymsg |             #   - a message with one of four channel types
    fromprovermsg | fromdisplaymsg 
   | internalmsg ) 
  }

pgips = element pgips { pgip+ }

pgip_attrs =
 attribute tag { text }?,                   # message tag, e.g. name of origin component (diagnostic)
 attribute id { text },                     # (unique) session id of this component 
 attribute destid { text }?,                # session id of destination component
 attribute class { pgip_class },            # general categorization of message
 attribute refid { text }?,                 # component id this message responds to (usually destid)
 attribute refseq { xsd:positiveInteger }?, # message sequence this message responds to
 attribute seq { xsd:positiveInteger }      # sequence number of this message

pgip_class = "pg"      # message sent TO proof general broker
           | "pa"      # message sent TO the proof assistant/other component
           | "pd"      # message sent TO display/front-end components

toprovermsg =          # Messages sent to the prover (class "pa"):
   proverconfig        #   query Prover configuration, triggering interface configuration
 | provercontrol       #   control some aspect of Prover
 | improperproofcmd    #   issue a proof command 
 | improperfilecmd     #   issue a file command
 | properproofcmd      #   [ NB: not strictly needed: input PGIP processing not expected ]
 | properfilecmd       #   [ NB: not strictly needed: input PGIP processing not expected ]
 | proofctxt           #   issue a context command

fromprovermsg =        # Messages from the prover to PG (class "pg"):
   kitconfig           #   messages to configure the interface 
 | proveroutput        #   output messages from the prover, usually display in interface
 | fileinfomsg         #   information messages concerning file-system access / prover state

todisplaymsg =         # Messages sent to display components (class "pd"):
   brokermsg           #   status reports from broker
 | dispmsg             #   display commands
                       #   - Further, all fromprovermsg can be relayed to display

fromdisplaymsg =       # Messages sent from display components (class "pg"):
   dispcmd             #   display messages 
 | brokercontrol       #   messages controlling broker & prover processes
		       #   - Further, all toprovermsg to be relayed to prover

# ===========================================================================
# 2. Component Control
# ===========================================================================

#
# Idea:  - broker knows how to manage some components (inc provers) as child processes,
#          communicate via pipes.  Configured by a fixed PGIP config file read on startup.
#        - other components may connect to running broker
#
# TODO: - describe startup protocol for component connecting to to running broker dynamically.

# This is the element contained in the configuration file read by the 
# broker on startup.
pgipconfig = element pgipconfig { componentspec* }

componentspec = 
   element componentspec {
      componentid_attr,         # Unique identifier for component class
      componentname_attr,       # Textual name of component class
      componenttype,            # Type of component: prover, display, auxiliary
      systemattrs,              # System attributes for connecting to component
      componentconnect          # How to connect to component
   }

componentid_attr   = attribute componentid   { token }
componentname_attr = attribute componentname { text }

componenttype = element componenttype {
     provercomponent 
   | displaycomponent 
 # | filehandlercomponent 
   | parsercomponent 
   | othercomponent }

provercomponent  = element provercomponent { empty }
displaycomponent = element displaycomponent { attribute active { xsd:boolean}? }
parsercomponent  = element parsercomponent  { componentid_attr }
othercomponent   = element othercomponent { empty }

componentconnect =
   componentsubprocess | componentsocket | connectbyproxy

componentsubprocess = 
   element syscommand { text }
componentsocket = 
   (element host { text }, element port { text })
connectbyproxy = 
   (element proxy { attribute host { text }    # Host to connect to
		  , attribute connect { 
                           "rsh" | "ssh" # Launch proxy via RSH or SSH, needs
			                 # authentication 
                         | "server"  # connect to running proxy on given port
                         }?
                  , attribute user { text } ? # user to connect as with RSH/SSH
		  , attribute port { text } ? # port to connect to running proxy
		  , componentconnect
		  })

systemattrs = (
   attribute timeout { xsd:integer }?,  # timeout for communications
   attribute sync { xsd:boolean }?,     # whether to wait for ready
   attribute startup {		# what to do on broker startup:
             "boot"   |		# always start this component (default with displays)
             "manual" |		# start manually (default with provers)
             "ignore"		# never start this
             }?
   )

# Control commands from display to broker
brokercontrol = 
    launchprover		# Launch a new prover
  | exitprover			# Request to terminate a running prover
  | restartprover		# Request to restart/reset a running prover
  | proversquery		# Query about known provers, running provers
  | shutdownbroker		# Ask broker to exit (should be wary of this!)
  | brokerstatusquery		# Ask broker for status report
  | pgipconfig			# Send config to broker

provername_attr    = attribute provername { provername }
provername         = token

proverid_attr     = attribute proverid  { proverid }
proverid          = token

launchprover      = element launchprover { componentid_attr }
exitprover        = element exitprover { proverid_attr }
restartprover     = element restartprover { proverid_attr }
proversquery      = element proversavailable { empty }
brokerstatusquery = element brokerstatusquery { empty } 
shutdownbroker    = element shutdownbroker { attribute force { xsd:boolean }? } 

# Control messages from broker to interface
brokermsg  = 
    brokerstatus		# response to brokerstatusquery:
  | proveravailmsg		# announce new prover is available
  | newprovermsg		# new prover has started 
  | proverstatemsg		# prover state has changed (busy/ready/exit)

brokerstatus  = element brokerstatus 
                       { knownprovers, runningprovers, brokerinformation }

knownprover   = element knownprover   { componentid_attr, provername }
runningprover = element runningprover { proverid_attr, provername }

knownprovers   = element knownprovers { knownprover* }
runningprovers = element runningprovers { runningprover* }
brokerinformation = element brokerinformation { text }

proveravailmsg  = element proveravailable { provername_attr,
                                            componentid_attr }
newprovermsg    = element proverstarted { provername_attr, 
		                          proverid_attr }
                  # QUESTION: do we want  componentid_attr 
                  # here as well, and do we want to be able to run multiple
                  # copies of the same prover? 
proverstatemsg = element proverstate { 
                       proverid_attr, provername_attr,
                       attribute proverstate {proverstate} } 

proverstate    = ("ready" | "busy" | "exitus")

# FIXME: This only allows provers to be available which are configured.
#        In the long run, we want to change configurations while running.


# ===========================================================================
# 3. Display Commands
# ===========================================================================

# Messages exchanged between broker and display

                        
dispcmd = dispfilecmd | dispobjcmd  # display commands go from display to broker
dispmsg = dispfilemsg | dispobjmsg  # display messages go from broker to display
   

dispfilecmd = 
    loadparsefile		# parse and load file
  | newfilewith			# create new source file with given text
  | dispopenfile		# open (or create) new file 
  | savefile			# save opened file
  | discardfile			# discard changes to opened file

dispfilemsg =
    newfile			# announce creation of new file (in response to load/open)
  | filestatus			#announce change in status of file in broker

# unique identifier of loaded files
srcid_attr = attribute srcid { text }

loadparsefile = element loadparsefile { url_attr, proverid_attr }
newfilewith   = element newfilewith   { url_attr, proverid_attr, text }
dispopenfile  = element dispopenfile { url_attr,
                                       proverid_attr,
                                       attribute overwrite { xsd:boolean }?}
savefile      = element savefile { srcid_attr,     
                                   url_attr? }
discardfile   = element discardfile { srcid_attr }

newfile       = element newfile  { proverid_attr, srcid_attr, url_attr }
filestatus    = element filestatus  { proverid_attr, srcid_attr, newstatus_attr, 
				      datetime_attr} 

newstatus_attr = attribute newstatus { "saved" | "changed" | "discarded" }

dispobjcmd =
    setobjstate			# request of change of state 
  | editobj			# request edit operation of opbjects
  | createobj			# request creation of new objects
  | inputcmd		        # process the command (generated by an input event)
  | interruptprover		# send interrupt or kill signal to prover

dispobjmsg = element dispobjmsg { 
      newobj+			# new objects have been created
    | delobj+			# objects have been deleted
    | replaceobjs		# objects are being replaced
    | objectstate+		# objects have changed state
    }

newobj = element newobj {
	    proverid_attr,
            srcid_attr, 
	    objid_attr, 
            attribute objposition { objid } ?,
            objtype_attr ?,
            attribute objparent { objid }?,
            attribute objstate { objstate },
            (properscriptcmd | unparseable) }

replaceobjs = element replaceobjs {
	                srcid_attr,
	                attribute replacedfrom { objid }? ,
			attribute replacedto { objid }?,
                        delobj*,
                        newobj+ }

delobj = element delobj   { proverid_attr, srcid_attr, objid_attr }

objectstate = element objstate
                       { proverid_attr, srcid_attr, objid_attr,
                         attribute newstate {objstate} }

setobjstate = element setobjstate
                  {  objid_attr, attribute newstate {objstate} }

editobj = element editobj { srcid_attr ?,
	                    attribute editfrom { objid }?,
                            attribute editto   { objid }?,
                            text }
createobj = element createobj { srcid_attr ?, 
                                attribute objposition { objid }?, 
                                text}

inputcmd       = element inputcmd { improper_attr, text }
improper_attr  = attribute improper { xsd:boolean }

interruptprover = element interruptprover 
                          { interruptlevel_attr, proverid_attr }

interruptlevel_attr  = attribute interruptlevel { "interrupt" | "stop" | "kill" }

objid_attr = attribute objid { objid } 
objid      = text 

objstate = 
  ( "unparseable" | "parsed" | "being_processed" | "processed" | "outdated" )


# ==============================================================================
#  4. Prover Configuration
# ==============================================================================

proverconfig =      
   askpgip			# what version of PGIP do you support?
 | askpgml			# what version of PGML do you support?
 | askconfig			# tell me about objects and operations
 | askprefs			# what preference settings do you offer?
 | setpref			# please set this preference value 
 | getpref			# please tell me this preference value



prefcat_attr = attribute prefcategory { text}   # e.g. "expert", "internal", etc.
                                                # could be used for tabs in dialog

askpgip   = element askpgip   { empty }
askpgml   = element askpgml   { empty }
askconfig = element askconfig { empty }
askprefs  = element askprefs  { prefcat_attr? }
setpref   = element setpref   { name_attr, prefcat_attr?, pgipvalue }
getpref   = element getpref   { name_attr, prefcat_attr? }

 

# ==============================================================================
#  5. Interface Configuration
# ==============================================================================

kitconfig =        
    usespgip			# I support PGIP, version ..
  | usespgml			# I support PGML, version ..
  | pgmlconfig			# configure PGML symbols
  | proverinfo			# Report assistant information
  | hasprefs			# I have preference settings ...
  | prefval			# the current value of a preference is
  | displayconfig		# configure the following object types and operations
  | setids			# inform the interface about some known objects
  | addids			# add some known identifiers
  | delids			# retract some known identifers
  | idvalue			# display the value of some identifier
  | menuadd			# add a menu entry
  | menudel			# remove a menu entry

# version reporting
version_attr  = attribute version { text }
usespgml = element usespgml  { version_attr }
usespgip = element usespgip  { version_attr 
	                     , activecompspec
			     }

# These data from the component spec which an active component can override, or which
# components initiating contact with the broker (e.g. incoming socket connections).
# There are some restrictions: if we start a tool, the componentid and the type must be the
# same as initially specified.
activecompspec =  ( componentid_attr?   # unique identifier of component class
	          , componentname_attr? # Textual name of this component (overrides initial spec)
		  , componenttype?      # Type of component
		  , acceptedpgipelems?  # list of accepted elements
		  )


acceptedpgipelems = element acceptedpgipelems { singlepgipelem* }

singlepgipelem    = element pgipelem { 
   attribute async { xsd:boolean }?,  # true if this command supported asynchronously (deflt false)
   text }                             # (otherwise part of ready/sync stream)

# PGML configuration
pgmlconfig = element pgmlconfig { pgmlconfigure+ }

# Types for config settings: corresponding data values should conform to canonical
# representation for corresponding XML Schema 1.0 Datatypes.  (This representation is verbose
# but helps for error checking later)
#
# In detail:
#  pgipbool   = xsd:boolean = true | false
#  pgipint    = xsd:integer = (-)?(0-9)+     (canonical: no leading zeroes)
#  pgipstring = xsd:string  =  <any character sequence>
#  pgipchoice = cf xs:choice  = type1 | type2 | ... | typen

pgiptype   = pgipbool | pgipint | pgipstring | pgipchoice | pgipconst
pgipbool   = element pgipbool { empty }

pgipint    = element pgipint  { min_attr?, max_attr?, empty }
min_attr   = attribute min { xsd:integer }
max_attr   = attribute max { xsd:integer }
pgipstring = element pgipstring { empty }
pgipchoice = element pgipchoice { pgiptype+ }
pgipconst  = element pgipconst { name_attr?, text }

pgipvalue  = text

icon  = element icon { xsd:base64Binary }  # image data for an icon

default_attr = attribute default { text }
descr_attr   = attribute descr { text }

# icons for preference recommended size: 32x32 
# top level preferences: may be used in dialog for preference setting
# object preferences: may be used as an "emblem" to decorate 
# object icon (boolean preferences with default false, only)
haspref = element haspref  { 
   name_attr, descr_attr?, 
   default_attr?, icon?,
   pgiptype
}

hasprefs = element hasprefs { prefcat_attr?, haspref* }

prefval = element prefval { name_attr, pgipvalue } 

# menu items (incomplete, FIXME)
path_attr = attribute path { text }

menuadd  = element menuadd  { path_attr?, name_attr?, opn_attr? }
menudel  = element menudel  { path_attr?, name_attr? }
opn_attr = attribute operation { token }


# Display configuration information: 
# basic prover information, lexical structure of files, 
# an icon for the prover, help documents, and the 
# objects, types, and operations for building proof commands.

# NB: the following object types have a fixed interpretation 
# in PGIP:  "comment", "theorem", "theory", "file" 

displayconfig =
  element displayconfig { 
     welcomemsg?, icon?, helpdoc*, lexicalstructure*,
     objtype*, opn* }

objtype = element objtype { name_attr, descr_attr?, icon?, hasprefs?, contains* }

objtype_attr = attribute objtype { token }           # the name of an objtype
contains = element contains { objtype_attr, empty }  #  a container for other objtypes

opn   = element opn { name_attr, inputform?, opsrc, optrg, opcmd, improper_attr? }

opsrc = element opsrc { list { token* } }  # source types: a space separated list
optrg = element optrg { token }?           # single target type, empty for proof command
opcmd = element opcmd { text }             # prover command, with printf-style "%1"-args

# interactive operations - require some input
inputform = element inputform { field+ }  

# a field has a PGIP config type (int, string, bool, choice(c1...cn)) and a name; under that
# name, it will be substituted into the command Ex. field name=number opcmd="rtac %1 %number"

field = element field { 
   name_attr, pgiptype,
   element prompt { text }
}

# identifier tables: these list known items of particular objtype.
# Might be used for completion or menu selection, and inspection.
# May have a nested structure (but objtypes do not).

setids  = element setids { idtable* }   # (with an empty idtable, clear table)
addids  = element addids { idtable* }
delids  = element delids { idtable* }

# give value of some identifier (response to showid)
idvalue = element idvalue               
   {  name_attr, objtype_attr, pgmltext }

idtable    = element idtable { context_attr?, objtype_attr, identifier* }
identifier = element identifier { token }

context_attr = attribute context { token } # parent identifier (context) 

instance_attr = attribute instance { text }

# prover information: 
# name, instance (e.g. in case of major parameter of invocation);
# description, version, homepage,  welcome message, docs available
proverinfo = element proverinfo 
   { name_attr, version_attr?, instance_attr?,
     descr_attr?, url_attr?, filenameextns_attr?, 
## TEMP: these elements are duplicated in displayconfig, as they're
## moving there.  
      welcomemsg?, icon?, helpdoc*, lexicalstructure* }

welcomemsg = element welcomemsg { text }

# helpdoc: advertise availability of some documentation, given a canonical
# name, textual description, and URL or viewdoc argument.
# 
helpdoc = element helpdoc { name_attr, descr_attr, url_attr?, text } # text is arg to "viewdoc"

filenameextns_attr = attribute filenameextns { objnames }

# lexical structure of proof texts
lexicalstructure = 
   element lexicalstructure {
      keyword*,
      stringdelimiter*,
      escapecharacter?,
      commentdelimiter*,
      identifiersyntax?
   }

keyword = element keyword {
   attribute word { text },
   shorthelp?,
   longhelp? }

shorthelp = element shorthelp { text }   # one-line (tooltip style) help 
longhelp  = element longhelp { text }    # multi-line help

stringdelimiter = element stringdelimiter { text }  # should be a single char

# The escape character is used to escape strings and other special characters - in most languages it is \
escapecharacter = element escapecharacter { text }  # should be a single char

commentdelimiter = element commentdelimiter { 
   attribute start { text },
   attribute end { text }?,
   empty
  }


# syntax for ids: id = initial allowed*  or id = allowed+ if initial empty
identifiersyntax = element identifiersyntax { 
   attribute initialchars { text }?,
   attribute allowedchars { text }
}

# ==============================================================================
# 6. Prover Control
# ==============================================================================

provercontrol = 
   proverinit			# reset prover to its initial state
 | proverexit			# exit prover
 | startquiet			# stop prover sending proof state displays, non-urgent messages
 | stopquiet			# turn on normal proof state & message displays
 | pgmlsymbolson		# activate use of symbols in PGML output (input always understood)
 | pgmlsymbolsoff		# deactivate use of symbols in PGML output

proverinit     = element proverinit { empty }  
proverexit     = element proverexit { empty }
startquiet     = element startquiet { empty }  
stopquiet      = element stopquiet  { empty }  
pgmlsymbolson  = element pgmlsymbolson { empty }
pgmlsymbolsoff = element pgmlsymbolsoff { empty }


# General prover output/responses

# Nearly all prover output has an optional proverid attribute, except for the one which is 
# never seen by any display. This is set by the Broker to indicate the originating or referring
# prover. 
# Displays rendering these messages can rely on this attribute being set.

proveroutput =
   ready			# prover is ready for input
 | cleardisplay			# prover requests a display area to be cleared
 | proofstate			# prover outputs the proof state
 | normalresponse		# prover outputs some display
 | errorresponse		# prover indicates an error/warning/debug condition, with message
 | scriptinsert			# some text to insert literally into the proof script
 | metainforesponse		# prover outputs some other meta-information to interface
 | parseresult			# results of a <parsescript> request (see later)

ready = element ready { empty }

displayarea = "status"		# a status line
	    | "message"		# the message area (e.g. response buffer)
            | "display"		# the main display area (e.g. goals buffer)
	    | token		# prover-specified window name

cleardisplay = 
   element cleardisplay {
      proverid_attr?,
      attribute area { 
         displayarea | "all" } }           


proofstate = 
  element proofstate { proverid_attr?, pgml }

messagecategory =		# attribution of message
   "internal"			#  - internal debug message (interface should usually hide)
 | "information"		#  - user-level debug/info message (interface may hide)
 | "tracing"			#  - user-level "tracing" message (possibly voluminous)

normalresponse =                           
  element normalresponse { 
    proverid_attr?,
    attribute area { displayarea },
    attribute messagecategory { messagecategory }?, # optional extra category (e.g. tracing/debug)
    attribute urgent { "y" }?,                      # indication that message must be displayed
    pgmltext 
}

## Error messages:  these are different from ordinary messages in that
##		    they indicate an error condition in the prover, with a notion
##		    of fatality and (optionally) a location.  The interface may collect these
##		    messages in a log, display in a modal dialog, or in the specified
##		    display area if one is specified.

errorresponse = 
   element errorresponse { 
     proverid_attr?,
     attribute area { displayarea }?,
     attribute fatality { fatality },
     location_attrs,
     pgmltext
  }

fatality =	  # degree of error conditions:
   "nonfatal"     #  - warning message (interface should show message)
 | "fatal"        #  - error message (interface must show message)
 | "panic"        #  - shutdown condition, component exits (interface may show message)
 | "log"          #  - log message (interface must not show message, write to broker log file)
 | "debug"        #  - debug message (interface may show message, write to broker log file)
		   ## FIXME da: wondering if this is more appropriate than normal/internal above


# attributes describing a file location (for error messages, etc)
location_attrs = 
     attribute location_descr    { text }?,
     attribute location_url      { xsd:anyURI }?,
     attribute locationline      { xsd:positiveInteger }?,
     attribute locationcolumn    { xsd:positiveInteger }?,
     attribute locationcharacter { xsd:positiveInteger }?

scriptinsert = element scriptinsert { proverid_attr?, metavarid_attr?, text }


# metainformation is an extensible place to put system-specific information

value = element value { name_attr?, text }   # generic value holder

metainforesponse = 
   element metainforesponse { 
      proverid_attr?,
      attribute infotype { text },      # categorization of data
      value* }                          # data values


# ==============================================================================
# 7. Proof script markup and proof control 
# ==============================================================================

# properproofcmds are purely markup on native proof script text
properproofcmd =
    opengoal        # open a goal in ambient context
  | proofstep       # a specific proof command (perhaps configured via opcmd) 
  | closegoal       # complete & close current open proof (succeeds iff proven, may close nested pf)
  | giveupgoal      # close current open proof, retaining attempt in script (Isar oops)
  | postponegoal    # close current open proof, record as proof obl'n  (Isar sorry)  
  | comment         # a proof script comment; text probably ignored by prover 
  | whitespace      # a whitespace comment; text ignored by prover
  | spuriouscmd     # command ignored for undo, e.g. "print x", could be pruned from script
  | badcmd          # a command which should not be stored in the script (e.g. an improperproofcmd)
  | litcomment      # a literate comment (never passed to prover)
  | pragma	    # a document generating instruction (never passed to prover)

# improperproofcmds are commands which are never stored in the script
improperproofcmd =
    dostep        # issue a properproofcmd (without passing in markup)
  | undostep      # undo the last proof step issued in currently open goal 
  | redostep      # redo the last undone step issued in currently open goal (optionally supported)
  | abortgoal     # give up on current open proof, close proof state, discard history
  | forget        # forget a theorem (or named target), outdating dependent theorems
  | restoregoal   # re-open previously postponed proof, outdating dependent theorems

opengoal     = element opengoal     { display_attr?, thmname_attr?, text } # FIXME: add objprefval
proofstep    = element proofstep    { display_attr?, name_attr?, objtype_attr?, text }
closegoal    = element closegoal    { display_attr?, text }
giveupgoal   = element giveupgoal   { display_attr?, text }
postponegoal = element postponegoal { display_attr?, text }
comment      = element comment      { display_attr?, text }
whitespace   = element whitespace   { display_attr?, text }

display_attr = attribute nodisplay { xsd:boolean }  # whether to display in documentation

spuriouscmd  = element spuriouscmd { text }
badcmd       = element badcmd { text }

litcomment  = element litcomment { format_attr?, (text | directive)* }
directive   = element directive { (proofctxt,pgml) }
format_attr = attribute format { token }

pragma       = showhidecode | setformat
showhidecode = element showcode { attribute show { xsd:boolean } }
setformat    = element setformat { format_attr }

dostep       = element dostep { text }
undostep     = element undostep { empty }
redostep     = element redostep { empty }
abortgoal    = element abortgoal { empty }
forget       = element forget { thyname_attr?, name_attr?, objtype_attr? }
restoregoal  = element restoregoal { thmname_attr }

# empty objprefval element is used for object prefs in script markup 
objprefval = element objprefval { name_attr, val_attr, empty }
val_attr   = attribute value { text }




# =======================================================
# Inspecting the proof context, etc.

proofctxt =
    askids         # please tell me about identifiers (given objtype in a theory)
  | showid         # print value of an object
  | askguise       # please tell me about the current state of the prover
  | parsescript    # parse a raw proof script into proofcmds
  | showproofstate # (re)display proof state (empty if outside a proof)
  | showctxt       # show proof context
  | searchtheorems # search for theorems (prover-specific arguments)  
  | setlinewidth   # set line width for printing
  | viewdoc        # request some on-line help (prover-specific arg)

askids = element askids  { thyname_attr?, objtype_attr? }
	# Note that thyname_attr is *required* for certain objtypes (e.g. theorem).
	# This is because otherwise the list is enormous.
	# Perhaps we should make thyname_attr obligatory? 
	# With a blank entry (i.e. thyname="") allowed for listing theories, or for when 
	# you really do want to see everything.

showid = element showid  { thyname_attr?, objtype_attr, name_attr }

askguise = element askguise { empty }


# =======================================================
# Parsing proof scripts

# NB: parsing needs only be supported for "proper" proof commands,
# which may appear in proof texts.  The groupdelimiters are purely
# markup hints to the interface for display structure on concrete syntax.
# The location attributes can be used by the prover in <parsescript> to
# generate error messages for particular locations; they can be used 
# in <parseresult> to pass position information back to the display,
# particularly in the case of (re-)parsing only part of a file.
# The parsing component MUST return the same location attributes
# (and system data attribute) that was passed in.

parsescript = element parsescript
                 { location_attrs, systemdata_attr, text }
       
parseresult = element parseresult { location_attrs, systemdata_attr,
				    singleparseresult* }

singleparseresult  = properscriptcmd | unparseable | errorresponse

unparseable = element unparseable { text }
properscriptcmd = properproofcmd | properfilecmd | groupdelimiter


groupdelimiter = openblock | closeblock
openblock  = element openblock { metavarid_attr? }
closeblock = element closeblock { empty }

# 
metavarid_attr = attribute metavarid { token }

showproofstate = element showproofstate { empty }
showctxt       = element showctxt { empty }
searchtheorems = element searchtheorems { text }
setlinewidth   = element setlinewidth { xsd:positiveInteger }
viewdoc        = element viewdoc { text }


# =======================================================
# Theory/file handling

properfilecmd =     # (NB: properfilecmds are purely markup on proof script text)
    opentheory      # begin construction of a new theory.  
  | theoryitem      # a step in a theory (e.g. declaration/definition of type/constant).
  | closetheory     # complete construction of the currently open theory

improperfilecmd = 
    doitem	    # issue a proper file command (without passing in markup)
  | undoitem	    # undo last step (or named item) in theory construction
  | redoitem	    # redo last step (or named item) in theory construction (optionally supported)
  | aborttheory     # abort currently open theory
  | retracttheory   # retract a named theory
  | openfile        # lock a file for constructing a proof text 
  | closefile       # unlock a file, suggesting it has been processed
  | abortfile       # unlock a file, suggesting it hasn't been processed
  | loadfile        # load a file possibly containing theory definition(s)
  | changecwd       # change prover's working directory (or load path) for files
  | systemcmd       # system (other) command, parsed internally

fileinfomsg = 
   informfileloaded       # prover informs interface a particular file is loaded
 | informfileretracted    # prover informs interface a particular file is outdated
 | informguise		  # prover informs interface about current state

opentheory    = element opentheory    { thyname_attr, parentnames_attr?, text }
closetheory   = element closetheory   { text }
theoryitem    = element theoryitem    { name_attr?, objtype_attr?, text } # FIXME: add objprefval

doitem        = element doitem        { text } 
undoitem      = element undoitem      { name_attr?, objtype_attr? } 
redoitem      = element redoitem      { name_attr?, objtype_attr? } 
aborttheory   = element aborttheory   { empty }
retracttheory = element retracttheory { thyname_attr }

parentnames_attr = attribute parentnames { objnames }


# Below, url_attr will often be a file URL.  We assume for now that
# the prover and interface are running on same filesystem.
#

openfile      = element openfile  { url_attr }	    # notify begin reading from given file
closefile     = element closefile { empty }	    # notify currently open file is complete
abortfile     = element abortfile { empty }	    # notify currently open file is discarded
loadfile      = element loadfile  { url_attr }	    # ask prover to read file directly
changecwd     = element changecwd { dir_attr }	    # ask prover to change current working dir

# this one not yet implemented, but would be handy.  Perhaps could be 
# locatethy/locatefile instead.
#locateobj     = element locateobj { name_attr, objtype_attr } # ask prover for file defining obj

informfileloaded    = element informfileloaded    { url_attr }  # prover indicates a processed file
informfileretracted = element informfileretracted { url_attr }  # prover indicates an undone file
informfilelocation  = element informfilelocation  { url_attr }  # response to locateobj

informguise = 
   element informguise {
      element guisefile { url_attr }?,
      element guisetheory { thyname_attr }?,
      element guiseproof { thmname_attr?, proofpos_attr? }?
   }

proofpos_attr = attribute proofpos { xsd:nonNegativeInteger }

systemcmd     = element systemcmd     { text }		# "shell escape", arbitrary prover command!

# ==============================================================================
# 8. Internal messages-- only used between communicating brokers.
# ==============================================================================
internalmsg  = launchcomp | stopcomp | registercomp | compstatus

launchcomp   = element launchcomponent { componentspec }
	               # request to start an instance of this component remotely
stopcomp     = element stopcomponent { attribute sessionid { string } }
                       # request to stop component with this session id remotely

registercomp = element registercomponent { activecompspec } 
                       # component has been started successfully
compstatus   = element componentstatus { componentstatus_attr    # status
	                               , componentid_attr?       # component id (for failure)
	                               , element text { text }?  # user-visible error message
				       , element info { text }?  # Additional info for log files.
				       }	
                       # component status: failed to start, or exited

componentstatus_attr = attribute status { ("fail"   # component failed to start
 		                          |"exit"  # component exited
					  )}	

# Local variables:
# fill-column: 95
# End:
# ==============================================================================
# end of `pgip.rnc'.

