logstash-core/lib/logstash/config/grammar.treetop

require "treetop/runtime"
require "logstash/config/config_ast"

grammar LogStashConfig
  rule config
    cs plugin_section cs (cs plugin_section)* cs <LogStash::Config::AST::Config>
  end

  rule comment
    (whitespace? "#" [^\r\n]* "\r"? "\n")+ <LogStash::Config::AST::Comment>
  end

  rule cs
    (comment / whitespace)* <LogStash::Config::AST::Whitespace>
  end

  rule whitespace
    [ \t\r\n]+ <LogStash::Config::AST::Whitespace>
  end

  rule plugin_section
    plugin_type cs "{"
      cs (branch_or_plugin cs)*
    "}"
    <LogStash::Config::AST::PluginSection>
  end

  rule branch_or_plugin
    branch / plugin
  end

  rule plugin_type
    ("input" / "filter" / "output")
  end

  rule plugins
    (plugin (cs plugin)*)?
    <LogStash::Config::AST::Plugins>
  end

  rule plugin
    name cs "{"
      cs
      attributes:( attribute (whitespace cs attribute)*)?
      cs
    "}"
    <LogStash::Config::AST::Plugin>
  end

  rule name
    (
      ([A-Za-z0-9_-]+ <LogStash::Config::AST::Name>)
      / string
    )
  end

  rule attribute
    name cs "=>" cs value
    <LogStash::Config::AST::Attribute>
  end

  rule value
    plugin / bareword / string / number / array / hash
  end

  rule array_value
    bareword / string / number / array / hash
  end

  rule bareword
    [A-Za-z_] [A-Za-z0-9_]+
    <LogStash::Config::AST::Bareword>
  end

  rule double_quoted_string
    ( '"' ( '\"' / !'"' . )* '"' <LogStash::Config::AST::String>)
  end

  rule single_quoted_string
    ( "'" ( "\\'" / !"'" . )* "'" <LogStash::Config::AST::String>)
  end

  rule string
    double_quoted_string / single_quoted_string
  end

  rule regexp
    ( '/' ( '\/' / !'/' . )* '/'  <LogStash::Config::AST::RegExp>)
  end

  rule number
    "-"? [0-9]+ ("." [0-9]*)?
    <LogStash::Config::AST::Number>
  end

  rule array
    "["
    cs
    (
      value (cs "," cs value)*
    )?
    cs
    "]"
    <LogStash::Config::AST::Array>
  end

  rule hash
    "{"
      cs
      hashentries?
      cs
    "}"
    <LogStash::Config::AST::Hash>
  end

  rule hashentries
    hashentry (whitespace hashentry)*
    <LogStash::Config::AST::HashEntries>
  end

  rule hashentry
    name:(number / bareword / string) cs "=>" cs value
    <LogStash::Config::AST::HashEntry>
  end

  # Conditions
  rule branch
    if (cs else_if)* (cs else)?
    <LogStash::Config::AST::Branch>
  end

  rule if
    "if" cs condition cs "{" cs (branch_or_plugin cs)* "}"
    <LogStash::Config::AST::If>
  end

  rule else_if
    "else" cs "if" cs condition cs "{" cs ( branch_or_plugin cs)* "}"
    <LogStash::Config::AST::Elsif>
  end

  rule else
    "else" cs "{" cs (branch_or_plugin cs)* "}"
    <LogStash::Config::AST::Else>
  end

  rule condition
    expression (cs boolean_operator cs expression)*
    <LogStash::Config::AST::Condition>
  end

  rule expression
    (
        ("(" cs condition cs ")")
      / negative_expression
      / in_expression
      / not_in_expression
      / compare_expression
      / regexp_expression
      / rvalue
    ) <LogStash::Config::AST::Expression>
  end

  rule negative_expression
    (
        ("!" cs "(" cs condition cs ")")
      / ("!" cs selector)
    ) <LogStash::Config::AST::NegativeExpression>
  end

  rule in_expression
    rvalue cs in_operator cs rvalue
    <LogStash::Config::AST::InExpression>
  end

  rule not_in_expression
    rvalue cs not_in_operator cs rvalue
    <LogStash::Config::AST::NotInExpression>
  end

  rule in_operator
    "in"
  end

  rule not_in_operator
    "not " cs "in"
  end

  rule rvalue
    string / number / selector / array / method_call / regexp
  end

  rule method_call
      method cs "(" cs
        (
          rvalue ( cs "," cs rvalue )*
        )?
      cs ")"
    <LogStash::Config::AST::MethodCall>
  end

  rule method
    bareword
  end

  rule compare_expression
    rvalue cs compare_operator cs rvalue
    <LogStash::Config::AST::ComparisonExpression>
  end
  
  rule compare_operator 
    ("==" / "!=" / "<=" / ">=" / "<" / ">") 
    <LogStash::Config::AST::ComparisonOperator>
  end

  rule regexp_expression
    rvalue cs  regexp_operator cs (string / regexp)
    <LogStash::Config::AST::RegexpExpression>
  end

  rule regexp_operator
    ("=~" / "!~") <LogStash::Config::AST::RegExpOperator>
  end


  rule boolean_operator
    ("and" / "or" / "xor" / "nand")
    <LogStash::Config::AST::BooleanOperator>
  end

  rule selector
    selector_element+
    <LogStash::Config::AST::Selector>
  end

  rule selector_element
    "[" [^\]\[,]+ "]"
    <LogStash::Config::AST::SelectorElement>
  end

end