yggdrasil-shared 0.2.5

grammar language {
    // name: "Yggdrasil"
}

using std;
// cast to same shape
#cast(std::Namespace)
// add value to structure
#attach(a: true)


entry class Program {
    Statement*
}

union Statement {
    | ClassStatement #Class
    | UnionStatement #Union
    | MacroStatement #Macro
}
// =================================================================================================
class GrammarStatement {
    Identifier
}
class KW_GRAMMAR {
    "grammar"
}


// =================================================================================================
// import
// =================================================================================================
class ClassStatement {
    Modifiers ^KW_CLASS Identifier OutType? RuleBody
}

class RuleBody {
    '{' ('|'? Expr)? '}'
}
// =================================================================================================
class UnionStatement {
    Modifiers ^KW_UNION Identifier OutType? RuleBody
}

class OutType {
    "->" Namepath
}
// =================================================================================================
class MacroStatement {
    KW_MACRO
}
// =================================================================================================
atomic class EOS {
    ";"
}

union ImportStatement {
    | "import" (path:String) ("as" Identifier)?   #FromPath
    | "import" (path:String) _ImportSelected      #FromPathItems
}

class _ImportSelected {
    '{' @join(items:ImportItem, ',')? '}'
}

class ImportItem {
    symbol:Identifier ("as" alias:Identifier)?
}
// =================================================================================================
#rewrite
climb Expr {
    | Atom                                             #Atom
    | '(' '|'? x:Self ')'                              #Group
    | '!' x:Self                                       #Negative
    | '^' x:Self                                       #Remark
    | x:Self '{' s:Integer? ',' e:Integer? '}'         #Range
    | x:Self '+'                                       #Repeat1
    | x:Self '*'                                       #Repeats
    | x:Self '?'                                       #Optional
    | x:Self y:Self                                    #Concat
    | x:Self '~' y:Self                                #ConcatSoft
    | x:Self xm:BranchMark? '|' y:Self ym:BranchMark?  #Choice
}
// =================================================================================================
class BranchMark {
    '#' Identifier RightAssociate?
}
class RightAssociate {
    '>'
}
// `_` inline a item even if it not mark as automatic inline
union Atom {
    | Identifier
    | String
    | Integer
    | Decimal
    | Regex
    | MacroCall
}
// =================================================================================================
class String {
    | '"' '"'
    | "'" "'"
}
// =================================================================================================
class Regex {
    '/' '/'
}

class MacroCall {
    '@' Identifier _MacroCallArgument?
}
class _MacroCallArgument {
    '(' ')'
}

// =================================================================================================
atomic class Integer {
    0 | [1-9][_0-9]
}
atomic class Decimal {
    Integer '.' Integer
}
// =================================================================================================
class Modifiers {
    (!(KW_CLASS | KW_UNION | KW_MACRO | KW_CLIMB) Identifier)*
}
class Namepath {
    Identifier (("::" | ".") Identifier)*
}
#string
atomic class Identifier {
    ("_" | XID_START) XID_CONTINUE*
}
#string
class Boolean {
    "true" | "false"
}
class AnyThing {
    "any"
}
// =================================================================================================
atomic token keywords {
    KW_GRAMMAR: "grammar"
    KW_IMPORT: "import" | "using"
    KW_CLASS: "class" | "struct" | "rule"
    KW_UNION: "union" | "enum"
    KW_CLIMB: "climb"
    KW_MACRO: "define" | "def" | "function" | "fun" | "fn" | "macro"
}
// =================================================================================================
#ignored
class WhiteSpace {
    UNICODE_WHITESPACE
}

#ignored
atomic class CommentLine {
    (!"///" "//") (!\n ANY)*
}
atomic class CommentDocument {
    "///" (!\n ANY)*
}

#parser(crate::utils::comment_block)
ignore class CommentBlock {

}