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<section id="ugr.tools.ruta.language.syntax">
  <title>Syntax</title>
  <para>
    UIMA Ruta defines its own language for writing rules and rule
    scripts. This section gives a formal overview of its syntax.
  </para>
  <para>
    Structure: The overall structure of a UIMA Ruta
    script is defined by
    the following syntax.
    <programlisting><![CDATA[Script              -> PackageDeclaration? GlobalStatements Statements
PackageDeclaration  -> "PACKAGE" DottedIdentifier ";"
GlobalStatments     -> GlobalStatement*   
GlobalStatment      -> ("SCRIPT" | "ENGINE" | "UIMAFIT") 
                       DottedIdentifier2 ";"
                       | ImportStatement
Statements          -> Statement*
Statement           -> Declaration | VariableDeclaration 
                        | BlockDeclaration | SimpleStatement ";"]]></programlisting>
    Comments are excluded from the syntax definition. Comments start with
    "//" and always go to the end of the line.
  </para>
  <para>
    Syntax of import statements:
   
    <programlisting><![CDATA[ImportStatement  -> (ImportType | ImportPackage | ImportTypeSystem) ";"
ImportType       -> "IMPORT" Type ("FROM" Typesystem)? 
                    ("AS" Alias)?
ImportPackage    -> "IMPORT" "PAKAGE" Package ("FROM" Typesystem)? 
                    ("AS" Alias)?
ImportTypeSystem -> "IMPORT" "PACKAGE" "*" "FROM" TypeSystem ("AS" Alias)?
                    | "IMPORT" "*" "FROM" Typesystem
                    | "TYPESYSTEM" Typesystem
Type             -> DottedIdentifier
Package          -> DottedIdentifier
TypeSystem       -> DottedIdentifier2
Alias            -> Identifier]]></programlisting>

    Example beginning of a UIMA Ruta file:
    <programlisting><![CDATA[PACKAGE uima.ruta.example;

// import the types of this type system 
// (located in the descriptor folder -> types folder)
IMPORT * FROM types.BibtexTypeSystem;

SCRIPT uima.ruta.example.Author;
SCRIPT uima.ruta.example.Title;
SCRIPT uima.ruta.example.Year;
]]></programlisting>

    Syntax of declarations:
    <programlisting><![CDATA[Declaration -> "DECLARE" (AnnotationType)? Identifier ("," Identifier )*
               | "DECLARE" AnnotationType? Identifier ( "("
               FeatureDeclaration ")" )?
FeatureDeclaration  -> ( (AnnotationType | "STRING" | "INT" | "FLOAT"
                       "DOUBLE" | "BOOLEAN") Identifier) )+
VariableDeclaration -> (("TYPE" Identifier ("," Identifier)*
                                                   ("=" AnnotationType)?)
                     | ("STRING" Identifier ("," Identifier)*
                                                 ("=" StringExpression)?)
                     | (("INT" | "DOUBLE" | "FLOAT") Identifier
                               ("," Identifier)* ("=" NumberExpression)?)
                     | ("BOOLEAN" Identifier ("," Identifier)*
                                                ("=" BooleanExpression)?)
                     | ("WORDLIST" Identifier ("=" WordListExpression)?)
                     | ("WORDTABLE" Identifier ("=" WordTableExpression)?)
                     | ("TYPELIST" Identifier ("=" TypeListExpression)?)
                     | ("STRINGLIST" Identifier
                                             ("=" StringListExpression)?)
                     | (("INTLIST" | "DOUBLELIST" | "FLOATLIST")
                                  Identifier ("=" NumberListExpression)?)
                     | ("BOOLEANLIST" Identifier
                                           ("=" BooleanListExpression)?))
AnnotationType      ->  BasicAnnotationType | declaredAnnotationType
BasicAnnotationType ->  ('COLON'| 'SW' | 'MARKUP' | 'PERIOD' | 'CW'| 'NUM'
                      | 'QUESTION' | 'SPECIAL' | 'CAP' | 'COMMA'
                      | 'EXCLAMATION' | 'SEMICOLON' | 'NBSP'| 'AMP' | '_'
                      | 'SENTENCEEND' | 'W' | 'PM' | 'ANY' | 'ALL'
                      | 'SPACE' | 'BREAK')
BlockDeclaration    -> "BLOCK" "(" Identifier ")" RuleElementWithCA
                                                       "{" Statements "}"]]></programlisting>

    Syntax of statements and rule elements:
    <programlisting><![CDATA[SimpleStatement        -> SimpleRule | RegExpRule | ConjunctRules 
                          | DocumentActionRule
SimpleRule             -> RuleElements ";"
RegExpRule             -> StringExpression "->" GroupAssignment 
                          ("," GroupAssignment)* ";"
ConjunctRules          -> RuleElements ("%" RuleElements)+ ";"
DocumentActionRule     -> Actions ";"
GroupAssignment        -> TypeExpression 
                        | NumberEpxression "=" TypeExpression
RuleElements           -> RuleElement+
RuleElement            -> RuleElementType | RuleElementLiteral
                        | RuleElementComposed | RuleElementWildCard
RuleElementType        ->  MatchReference OptionalRuleElementPart
RuleElementWithCA      ->  MatchReference ("{" Conditions?  Actions? "}")?
MatchReference         -> TypeExpression | FeatureMatchExpression
FeatureMatchExpression -> TypeExpression ( "." Feature)+ 
                          ( Operator (Expression | "null"))?
RuleElementLiteral     ->  SimpleStringExpression OptionalRuleElementPart
RuleElementComposed    -> "(" RuleElement ("&" RuleElement)+ ")"
                          | "(" RuleElement ("|" RuleElement)+ ")"
                          | "(" RuleElements ")"
                          OptionalRuleElementPart
OptionalRuleElementPart-> QuantifierPart? ("{" Conditions?  Actions? "}")?
                          InlinedRules?
InlinedRules           ->  ("<-" "{" SimpleStatement+ "}")?
                           ("->"  "{" SimpleStatement+ "}")?
RuleElementWildCard    -> "#"("{" Conditions?  Actions? }")? InlinedRules?
QuantifierPart         -> "*" | "*?" | "+" | "+?" | "?" | "??"
                        | "[" NumberExpression "," NumberExpression "]"
                        | "[" NumberExpression "," NumberExpression "]?"
Conditions             -> Condition ( "," Condition )*
Actions                -> "->" Action ( "," Action)*
]]></programlisting>
    Since each condition and each action has its own syntax, conditions
    and actions are described in their own section. For conditions see
    <xref linkend='ugr.tools.ruta.language.conditions' />
    , for actions see
    <xref linkend='ugr.tools.ruta.language.actions' />.
    The syntax of expressions is explained in
    <xref linkend='ugr.tools.ruta.language.expressions' />.
  </para>
  <para>
    It is also possible to use specific expression as implicit conditions or action additionally to the set of available conditions and actions.
        <programlisting><![CDATA[Condition -> BooleanExpression | FeatureMatchExpression
Action    -> TypeExpression | FeatureAssignmentExpression 
]]></programlisting>
  

  </para>
  
  
  <para>
    Identifier:
    <programlisting><![CDATA[DottedIdentifier    ->  Identifier ("." Identifier)*
DottedIdentifier2   ->  Identifier (("."|"-") Identifier)*
Identifier          ->  letter (letter|digit)*
]]></programlisting>
  </para>
</section>