parser:
  grammar.citrus
rules:
  ### units and tasks
  unit_def:
    - [ task_def ]
  task_def:
    - [task_name, some_def*, statement]
  some_def:
    - fluent_def
    - trackvar_def
    - task_def
  ### variables
  fluent_def:
    - [var_name, event_set, event_set, initially]
  trackvar_def:
    - [var_name, event_set, event_set, initially]
  event_set:
    - [event*]
  event:
    - event_name
    - task_event_name
  var_ref:
    - [var_name]
  ### statements
  statement:
    - if_st
    - case_st
    - while_st
    - seq_st
    - par_st
    - task_call_st
    - nop_st
  if_st:
    - [bool_expr, statement, elsif_clause*, "else_clause?"]
  case_st:
    - [[var_ref, ~], when_clause+, "else_clause?"]
  while_st:
    - [bool_expr, statement]
  seq_st:
    - [statement+]
  par_st:
    - [statement+]
  task_call_st:
    - [task_name]
  nop_st:
    - []
  ### clauses
  elsif_clause:
    - [bool_expr, statement]
  else_clause:
    - [statement]
  when_clause:
    - [bool_expr, statement]
  ### boolean expressions
  bool_expr:
    - [bool_expression]
  bool_expression:
    - bool_or
    - bool_and
    - bool_not
    - var_ref
    - bool_lit
  bool_or:
    - [bool_expression, bool_expression]
  bool_and:
    - [bool_expression, bool_expression]
  bool_not:
    - [bool_expression]
  bool_lit:
    - [ boolean_literal  ]
  boolean_literal:
    - true
    - false
  ### terminals
  task_name:       !ruby/regexp /^[A-Z][A-Za-z0-9_]*$/
  var_name:        !ruby/regexp /^[a-z][A-Za-z0-9_]*$/
  event_name:      !ruby/regexp /^[a-z][a-z0-9_]*$/
  task_event_name: !ruby/regexp /^[A-Z][A-Za-z0-9_]*:(start|end)$/
  initially:
    - true
    - false
    - ~