Grammar of Castile

This is an EBNF grammar for Castile.

Program ::= {Defn [";"]}.
Defn    ::= "fun" ident "(" [Arg {"," Arg}] ")" Body
          | "struct" ident "{" {ident ":" TExpr [";"]} "}" ["for" "(" [ident {"," ident}] ")"]
          | ident (":" TExpr0 | "=" Literal).
Arg     ::= ident [":" TExpr1].
Body    ::= "{" {Stmt [";"]} "}".
Stmt    ::= "while" Expr0 Block
          | "typecase" ident "is" TExpr0 Block
          | "do" Expr0
          | "return" Expr0
          | If
          | Expr0.
Block   ::= "{" {Stmt [";"]} "}".
If      ::= "if" Expr0 Block ["else" (Block | If)].
Expr0   ::= Expr1 {("and" | "or") Expr1} ["as" TExpr0].
Expr1   ::= Expr2 {(">" | ">=" | "<" | "<=" | "==" | "!=") Expr2}.
Expr2   ::= Expr3 {("+" | "-") Expr3}.
Expr3   ::= Expr4 {("*" | "/") Expr4}.
Expr4   ::= Expr5 {"(" [Expr0 {"," Expr0}] ")" | "." ident}.
Expr5   ::= "make" ident "(" [ident ":" Expr0 {"," ident ":" Expr0}] ")"
          | "(" Expr0 ")"
          | "not" Expr1
          | Literal
          | ident ["=" Expr0].
Literal ::= strlit
          | ["-"] intlit
          | "true" | "false" | "null"
          | "fun" "(" [Arg {"," Arg}] ")" Body.
TExpr0  ::= TExpr1 [{"," TExpr1} "->" TExpr1].
TExpr1  ::= TExpr2 {"|" TExpr2}.
TExpr2  ::= "integer"
          | "boolean"
          | "void"
          | "(" TExpr0 ")"
          | ident.