# The command line needs to obey a grammar.  It is then against this grammar
# that bugs will be identified.
# 
# Conventions:
#   - Literals are always double-quoted.
#   - "*", "+" and "?" suffixes have POSIX semantics.
#   - Low-level primitives are in <brackets>.
#   - @reports for dynamic lists such as custom report names.
# 
# The general form of commands is:
#   task [ all-commands ]
#

  grammar         ::= all-commands?
                    ;

  all-commands    ::= custom-report
                    | read-command
                    | write-command
                    | special-command
                    ;

  custom-report   ::= filter? @report ;
  read-command    ::= filter? @readcmd ;
  write-command   ::= filter? @writecmd modifiers ;
  special-command ::= ;

  filter          ::= expression ;

  expression      ::= ;

  modifiers       ::= ;

# Low-level:

  dom             ::= context-value
                    | system-value
                    | rc-value
                    | task-value
                    ;

  context-value   ::= "context.program"
                    | "context.args"
                    | "context.width"
                    | "context.height"
                    ;

  system-value    ::= "system.version"
                    | "system.os"
                    ;

  rc-value        ::= /rc\.[a-zA-Z.]+/
                    ;

  task-value      ::= <id> "." attribute
                    | <uuid> "." attribute
                    ;

  literal         ::= <string>
                    | <numeric>
                    | <date>
                    | <duration>
                    ;

# Supported primitives:
#
#  <id>
#  <uuid>
#  <override>
#  <string>
#  <numeric>
#  <date>
#  <duration>
#  @command      all commands
#  @report       all custom reports
#  @attributes   all attributes, UDAs
#  @readcmd      all read-only commands
#  @writecmd     all write commands