Program = Statement* PROGRAM_END

Statement = Enum / Interface / Module / Expression

Module = "EVERYTHING" _ "CHANGED" _ "WHEN" _ name:PASCAL_CASE _ "EXISTS" _ SCOPE_START _ body:ModuleBody _ SCOPE_END
ModuleBody = Constructor? _? Declaration*
Constructor = "PRACTICALLY" _ "IMPOSSIBLE" _ "TO" _ "HAVE" _ module:Identifier _ "WITHOUT" _ args:ArgList _ SCOPE_START _ body:FunctionBody _ SCOPE_END

Expression = FunctionCall / BinaryExpression / UnaryOperation / Literal / Declaration

FunctionCall = name:Identifier _ "OF" _ args:(Expression _? COMMA _?)* Expression

BinaryExpression = left:Expression op:BinaryOperation right:Expression
BinaryOperation = ArithmeticOperation / ComparisonOperation / BooleanOperation
ArithmeticOperation = "\\+" / "\\-" / "/" / "\\%" / "\\*\\*" / "\\*" / ">>" / "<<"
ComparisonOperation = "<" / ">" / "<=" / ">="
BooleanOperation = "\\|\\|" / "\\|" / "&&" / "&"

Declaration = VarDeclaration / FunctionDeclaration
VarDeclaration = "EXPERTS" _ "CLAIM" _ name:CAMEL_CASE _ "TO" _ "BE" _ Type _ val:(option:OptionMatch / "OF" _ expr:Expression)?
OptionMatch = "WHO" _ "IS" _ "DATING" _ SCOPE_START _ (some:SomeMatch _ none:NoneMatch) / (none:NoneMatch _ some:SomeMatch) _ SCOPE_END
SomeMatch = "Someone" LPAREN name:Identifier RPAREN _ "SO" _ expr:Expression 
NoneMatch = "Nobody" _ "SO" _ expr:Expression

Literal = String / Integer / Float / StructInit / Identifier
String = '(["\'])(?:(?=(\\\\?))\\2.)*?\\1'
Integer = "^-?0*\\d+$"
Float = "^-?\\d+(\\.\\d+)?$"

UnaryOperation = PrefixOperation Expression / Expression PostfixOperation
PrefixOperation = "!" / "~"
PostfixOperation = LBRACKET index:POSITIVE_INT RBRACKET

StructInit = "STUFF" _ "MADE" _ "OF" _ SCOPE_START _ init:Declaration* _ SCOPE_END

Type = name:(PASCAL_CASE / (PASCAL_CASE _ generic:Generic) / (tupleType:Type _ LBRACKET _ tupleLength:POSITIVE_INT _ RBRACKET) / union:(Type _ "OR" _ Type))
Generic = LPAREN _? generic:(Type _? COMMA _?)* Type RPAREN

FunctionDeclaration = FunctionSignature _ SCOPE_START _ body:FunctionBody _ SCOPE_END
FunctionBody = (Expression / ReturnStatement)*
FunctionSignature = "DISCOVER" _ "HOW" _ "TO" _ name:CAMEL_CASE _ "WITH" _ args:ArgList _ "GIVES" _ "YOU" _ type:Type
ArgList = args:(type:Type name:CAMEL_CASE COMMA _?)* type:Type name:CAMEL_CASE

ReturnStatement = "SHOCKING" _ "DEVELOPMENT" _ Expression

Interface = "STUFF" _ "OF" _ name:PASCAL_CASE _ "LOOKS" _ "LIKE" SCOPE_START methods:FunctionSignature*

Enum = "ONLY" _ "OPTIONS" _ "OF" name:PASCAL_CASE _ "ARE" _ SCOPE_START _ options:EnumBody* _ SCOPE_END
EnumBody = name:Identifier COMMA

Identifier = [a-zA-Z][\w\d|.]*

SCOPE_START = "RUMOR" _ "HAS" _ "IT"
SCOPE_END = "END" _ "OF" _ "STORY"
PROGRAM_END = "PLEASE" _ "LIKE" _ "AND" _ "SUBSCRIBE"
PASCAL_CASE = [A-Z][\w\d]*
CAMEL_CASE = [a-z][\w\d]*

LPAREN = "("
RPAREN = ")"
LBRACKET = "["
RBRACKET = "]"
COMMA = ","

POSITIVE_INT = [1-9][0-9]*

_ = [\s]+