railt/compiler

%include lexer

#Grammar
    : __definition()*
    ;

__definition
    : TokenDefinition()
    | PragmaDefinition()
    | IncludeDefinition()
    | RuleDefinition()
    ;

/**
 | ---------------------------------------------------------------------------------
 |  List of root structure definitions
 | ---------------------------------------------------------------------------------
 */

#TokenDefinition -> Railt\Component\Compiler\Grammar\Delegate\TokenDelegate
    : <T_TOKEN>
    | <T_SKIP>
    ;

#PragmaDefinition
    : <T_PRAGMA>
    ;

#IncludeDefinition -> Railt\Component\Compiler\Grammar\Delegate\IncludeDelegate
    : <T_INCLUDE>
    ;

/**
 | ---------------------------------------------------------------------------------
 |  Rule Definition
 | ---------------------------------------------------------------------------------
 */

#RuleDefinition -> Railt\Component\Compiler\Grammar\Delegate\RuleDelegate
    : ShouldKeep()? RuleName() RuleDelegate()?
        ::T_EQ:: RuleProduction() ::T_END_OF_RULE::?
    ;

#RuleName
    : <T_NAME>
    ;

#RuleDelegate
    : ::T_DELEGATE:: <T_NAME>
    ;

#ShouldKeep
    : ::T_KEPT_NAME::
    ;


#RuleProduction
    : __alternation()
    ;

__alternation
    : __concatenation()
    | Alternation()
    ;

#Alternation
    : __concatenation() ( <T_OR> __concatenation() )+
    ;

__concatenation
    : __repetition()
    | Concatenation()
    ;

#Concatenation
    : __repetition() __repetition()+
    ;

__repetition
    : ( __simple() | Repetition() ) Rename()?
    ;

#Repetition
    : __simple() Quantifier()
    ;

__simple
    : <T_GROUP_OPEN> __alternation() <T_GROUP_CLOSE>
    | <T_TOKEN_SKIPPED>
    | <T_TOKEN_KEPT>
    | <T_TOKEN_STRING>
    | <T_INVOKE>
    ;

#Quantifier
    : <T_REPEAT_ZERO_OR_ONE>
    | <T_REPEAT_ONE_OR_MORE>
    | <T_REPEAT_ZERO_OR_MORE>
    | <T_REPEAT_N_TO_M>
    | <T_REPEAT_ZERO_OR_MORE>
    | <T_REPEAT_ZERO_TO_M>
    | <T_REPEAT_N_OR_MORE>
    | <T_REPEAT_EXACTLY_N>
    ;

#Rename
    : <T_KEPT_NAME> <T_NAME>