grammar in readme

doc/README

@@ -24,3 +24,92 @@ and type in your program, you can use
   rlwrap ./scully
 
 for more input awesomeness. (http://utopia.knoware.nl/~hlub/rlwrap/#rlwrap)
+
+# Grammar
+
+// Symbols:
+//   0 $             10 T_LPAREN      20 T_FOR         30 expr        
+//   1 T_WHITESPACE  11 T_RPAREN      21 T_SEMICOLON   31 type        
+//   2 T_ASSIGN      12 T_BEGIN       22 T_RFOR        32 params      
+//   3 T_EQUALS      13 T_END         23 T_RETURN      33 statements  
+//   4 T_LESS        14 T_BOOL        24 T_CINT        34 statement   
+//   5 T_PLUS        15 T_INT         25 T_TRUE        35 vardef      
+//   6 T_MINUS       16 T_VOID        26 T_FALSE       36 values      
+//   7 T_TIMES       17 T_COMMA       27 error       
+//   8 T_DIV         18 T_IF          28 program     
+//   9 T_IDENTIFIER  19 T_RIF         29 fundef      
+program ::= fundef.
+program ::= expr.
+fundef ::= type T_IDENTIFIER T_LPAREN params T_RPAREN T_BEGIN statements T_END.
+type ::= T_BOOL.
+type ::= T_INT.
+type ::= T_VOID.
+params ::=.
+params ::= type T_IDENTIFIER.
+params ::= params T_COMMA type T_IDENTIFIER.
+statement ::= T_IF T_LPAREN expr T_RPAREN statement.
+statement ::= T_RIF T_LPAREN expr T_RPAREN statement.
+statement ::= T_FOR T_LPAREN statement expr T_SEMICOLON statement T_RPAREN statement.
+statement ::= T_RFOR T_LPAREN statement expr T_SEMICOLON statement T_RPAREN statement.
+statement ::= T_RETURN T_SEMICOLON.
+statement ::= T_RETURN expr T_SEMICOLON.
+statement ::= T_BEGIN statements T_END.
+statement ::= vardef T_SEMICOLON.
+statement ::= expr T_SEMICOLON.
+statements ::=.
+statements ::= statements statement.
+expr ::= T_IDENTIFIER.
+expr ::= T_IDENTIFIER T_ASSIGN expr.
+expr ::= expr T_EQUALS expr.
+expr ::= expr T_LESS expr.
+expr ::= expr T_PLUS expr.
+expr ::= expr T_MINUS expr.
+expr ::= expr T_TIMES expr.
+expr ::= expr T_DIV expr.
+expr ::= T_CINT.
+expr ::= T_TRUE.
+expr ::= T_FALSE.
+expr ::= T_IDENTIFIER T_LPAREN values T_RPAREN.
+vardef ::= type T_IDENTIFIER.
+values ::=.
+values ::= expr.
+values ::= values T_COMMA expr.
+
+# The Symbols are
+keywords:
+  "bool", T_BOOL
+  "for", T_FOR
+  "if", T_IF
+  "int", T_INT
+  "return", T_RETURN
+  "void", T_VOID
+  "rfor", T_RFOR
+  "rif", T_RIF
+
+special characters:
+  "dana", T_LPAREN
+  "fox", T_RPAREN
+  "mulder", T_BEGIN
+  "scully", T_END
+  ",", T_COMMA
+  ";", T_SEMICOLON
+
+operators:
+  "=", T_ASSIGN
+  "==", T_EQUALS
+  "<", T_LESS
+  "+", T_PLUS
+  "-", T_MINUS
+  "*", T_TIMES
+  "/", T_DIV
+
+constants:
+  "true", T_TRUE
+  "false", T_FALSE
+  "\\d+", T_CINT
+
+identifier:
+  "[a-zA-Z_][a-zA-Z_0-9]*", T_IDENTIFIER
+
+whitespace:
+  "\\s+", T_WHITESPACE