src/grammar.txt

   1 <Expr>         ::= <BinOrExpr> [':' <Expr>]
   2 <BinOrExpr>    ::= <BinAndExpr> ['||' <BinOrExpr>]
   3 <BinAndExpr>   ::= <CompareExpr> ['&&' <BinAndExpr>]
   4 <CompareExpr>  ::= <PlusMinExpr> [('==' | '<' | '>' | '<=' | '>=' | '!=') <CompareExpr>]
   5 <PlusMinExpr>  ::= <TimesDivExpr> (('+' | '-') <TimesDivExpr>)*
   6 <TimesDivExpr> ::= <BasicExpr> ('*' | '/' | '%'] <BasicExpr>)*
   7 <BasicExpr>    ::= <id> ['hd'|'tl'|'fst'|'snd]
   8                  | <Op1> <Expr>
   9                  | <int>
  10                  | <char>
  11                  | 'False'
  12                  | 'True'
  13                  | '(' <Expr> ')'
  14                  | <id> '(' [<ActArgs>] ')'
  15                  | '[]' <Expr>
  16                  | '(' <Expr> ',' <Expr> ')'
  17
  18 <ActArgs>      ::= <Expr> [',' ActArgs]
  19
  20 <VarDecl>      ::= (<Type> | 'var') <id> '=' <Expr> ';'
  21
  22 <Type>         ::= 'Int'
  23                  | 'Bool'
  24                  | 'Char'
  25                  | '(' Type ',' Type ')'
  26                  | '[' Type ']'
  27                  | <id>