import edu.neu.ccs.demeter.dj.*;
import java.util.*;


Main = <s> List(Item) EOF.
Item : Column | Declaration | Event.


Column = "column" <title> Title [Width] "is" <expr> Expr.
Title = String.
Width = "width" <width> Integer.


Declaration = "declare" <varname> Varname [<attribute> Attribute] ["=" <expr> Expr].
Attribute : Asset | Liability.
Asset = "asset".
Liability = "liability".
// Asset variables have their values added to the total savings every month.
// Liability variables have their values subtracted from the total savings every month.


Event = "event" <eventname> Eventname "is" [<shown> Shown] 
        <occurrence> Occurrence <statements> Statements "end".
Eventname = Ident.
Shown = "shown".
Occurrence : Once | Repeated.
Once = "once at" When.
When : Eventname | Date.

Date = Month Year.
Month : Jan | Feb | Mar | Apr | May | Jun | Jul | 
        Aug | Sep | Oct | Nov | Dec | MonthInteger.
Jan = "jan".
Feb = "feb".
Mar = "mar".
Apr = "apr".
May = "may".
Jun = "jun".
Jul = "jul".
Aug = "aug".
Sep = "sep".
Oct = "oct".
Nov = "nov".
Dec = "dec".
MonthInteger = Integer.
Year = Integer.
Repeated : Yearly | Monthly.
Yearly = "yearly every" Month.
Monthly = "monthly".


Statements = List(Statement).
Statement : Assignment | If_Then | While | Print | Dump | Stop.
Assignment = Varname "=" Expr.
If_Then = "if" Expr "then" <thenStmts> Statements 
          ["else" <elseStmts> Statements] "end".
While = "while" Expr "loop" Statements "end".
Stop = "stop".
Dump = "dump symboltable".
Print = "print" PrintOp.
PrintOp : lookahead (@ 2 @) PrintStrExp | PrintStr | PrintExp.
PrintStr = String.
PrintStrExp = String Expr.
PrintExp = Expr.

// Expression definition

Expr = BoolExpr.

BoolExpr = RelExpr BoolExpr_ .
BoolExpr_ : And | Or | EmptyBoolExpr.
And = "and" RelExpr <next> BoolExpr_ .
Or  = "or"  RelExpr <next> BoolExpr_ .
EmptyBoolExpr = .

RelExpr = NumExpr RelExpr_ .
RelExpr_ : GT | LT | GE | LE | EQ | NE | EmptyRelExpr.
GT = ">" NumExpr .
LT = "<" NumExpr  .
GE = ">=" NumExpr .
LE = "<=" NumExpr  .
EQ = "=" NumExpr .
NE = "!=" NumExpr .
EmptyRelExpr = .

NumExpr = Term NumExpr_.
NumExpr_ : Add | Sub | EmptyNumExpr .
Add = "+" Term <next> NumExpr_.
Sub = "-" Term <next> NumExpr_.
EmptyNumExpr = .

Term = Factor Term_.
Term_ : Mul | Div | EmptyTerm.
Mul = "*" Factor <next> Term_.
Div = "/" Factor <next> Term_.
EmptyTerm = .

Factor = UnaryOp Factor1.
UnaryOp : Negate | Not | EmptyUnary.
Negate = "-".
Not = "not".
EmptyUnary =.
Factor1 : Paren | SimpleFactor.
Paren = "(" Expr ")".
SimpleFactor = Simple.


Simple : lookahead (@ 2 @) DoubleLiteral | IntegerLiteral | Varname.
// Need lookahead to distinguish between integer and float literals.
IntegerLiteral = <v> Integer.
DoubleLiteral = <v> Double.
Varname = <v> Ident.

List(S) ~ {S}.


// these don't appear in object file:
Symbol = Varname [Attribute] [Value].
Value = <v> Double.
SymbolTable = List(Symbol).

// Visitors
visitor EvalVisitor = extends Visitor.
visitor InitSymbolTableVisitor = .
visitor SearchSymbolTableVisitor = <name> String extends Visitor.
visitor DumpSymbolTableVisitor = extends Visitor.
visitor ValueOfVisitor = extends Visitor.
visitor NameOfVisitor = extends Visitor.
visitor EventVisitor = <year> double <month> double.
visitor StatementVisitor = .
visitor ColumnTitleVisitor = .
visitor ColumnValueVisitor = <names> String.
visitor GetAttributeVisitor = .