Hazel Grammar

<exp> ::= | <bool> | <integer> | <float> | <string> | <variable> | "triv" | "nil" | "?" | <constructor> | <constructor>"(" <exp> ")" | "(" <exp> ")" | <exp> "::" <exp> | <exp> {"," <exp>} | "[" <exp> {"," <exp>} "]" | <unary-op> <exp> | <exp> <binary-op> <exp> | <exp>"("<exp>")" | "let" <pat> "=" <exp> "in" <exp> | "if" <exp> "then" <exp> "else" <exp> | "case" <exp> {"|" <pat> "=>" <exp>} "end" | <exp> ";" <exp> | "test" <exp> "end" | "type" <type-variable> "=" <typ> "in" <exp>

<type-variable> := regexp("^[A-Z][A-Za-z0-9_]*$") <constructor> := regexp("^[A-Z][A-Za-z0-9_]*$") <variable> :== := regexp("^[a-z][A-Za-z0-9_]*$") <bool> ::= "true" | "false" <integer> :== regexp("^[0-9_]*$") <float> :== regexp("^[0-9]*\\.[0-9]*$") <string> :== := regexp("^\".*\"")

<unary-op> ::= "-" <binary-op-int> ::= "+" | "-" | "*" | "\" | "<" | ">" | "<=" | ">=" | "==" <binary-op-float> ::= "+." | "-." | "*." | "\." | "<." | ">." | "<=." | ">=." | "==." <binary-op-string> ::= "$==" <binary-op> ::= <binary-op-int> | <binary-op-float> | <binary-op-string>

<pat> ::= | <bool> | <integer> | <float> | <string> | <variable> | "triv" | "nil" | "?" | <constructor> | <constructor>"(" <pat> ")" | "(" <pat> ")" | <pat> "::" <pat> | <pat> {"," <pat>} | "[" <pat> {"," <pat>} "]" | "_" | <pat> ":" <typ>

<typ> ::= | "Unit" | "Int" | "Float" | "Bool" | "String" | <type-variable> | <typ-constructor-def> "+" <typ-constructor-def> | "?" | "(" <typ> ")" | "[" <typ> "]" | <typ> "->" <typ> | <typ> {"," <typ>}

<typ-constructor-def> := <constructor> | <constructor "(" <typ> ")"