feat/schema: add parser

schema/azschema.bnf

@@ -4,15 +4,37 @@ _bin_digit: '0' - '1';
 _oct_digit: _bin_digit | '2' - '7';
 _dec_digit: _oct_digit | '8' - '9';
 _hex_digit: _dec_digit | 'A' - 'F' | 'a' - 'f';
-_negative: '-';
-number: [_negative] '0' 'b' _bin_digit {_bin_digit}
-    | [_negative] '0' 'o' _oct_digit {_oct_digit}
-    | [_negative] _dec_digit {_dec_digit}
-    | [_negative] '0' 'x' _hex_digit {_hex_digit};
+number: ['-' | '+'] '0' 'b' _bin_digit {_bin_digit | '_'}
+    | ['-' | '+'] '0' 'o' _oct_digit {_oct_digit | '_'}
+    | ['-' | '+'] _dec_digit {_dec_digit | '_'}
+    | ['-' | '+'] '0' 'x' _hex_digit {_hex_digit | '_'};
 
 _name_initial: 'A' - 'Z' | 'a' - 'z' | '_' | '~' | '!' | '@' | '#' | '$' | '%' | '^' | '&' | '*' | '-' | '_' | '+' | '=' | '?' | '/' | '.' | '\'';
 _name_char: _name_initial | _dec_digit;
 name: _name_initial {_name_char};
 
 !whitespace: ' ' | '\t' | '\n' | '\r';
-!comment: ';' {.} '\n';
+!comment: ';' {.} '\n';
+
+<<>>
+Schema: ExprList;
+ExprList
+    : Expr
+    | ExprList Expr
+    ;
+ValList
+    : Val
+    | ValList Val
+    ;
+Val
+    : string
+    | number
+    | name
+    | Expr
+    ;
+Expr
+    : "(" name Val Val ")"
+    | "(" name Val ")"
+    | "(" name ")"
+    | "(" "." ValList ")"
+    ;