## Identifiers

Lexis
  Id : id ::= ('a'-'z'|'A'-'Z') ('a'-'z'|'A'-'Z'|'0'-'9')*

Semantics
  id[[ Id:id ]] : => ids

Rule

  id[[ Id ]] = \"Id\"

## Numerals

Syntax
  Int : int ::= '-'? _ nat
Lexis
  Nat : nat ::= ('0'-'9')+

Semantics
  int-val[[ Int:int ]] : => integers

Rule

  int-val[[ '-' Nat ]] = integer-negate int-val[[Nat]]
Rule
  int-val[[ Nat ]] = decimal-natural \"Nat\"

## Strings

Syntax
  String : string ::= '"' _ string-chars _ '"'
Lexis
  StringChars : string-chars ::= string-char*
  
  string-char ::= ~( '"' | '\n' )

Semantics
  string-val[[ String:string ]] : => strings

Rule

  string-val[[ '"' StringChars '"' ]] = \"StringChars\"