Initial state - basic lexer + parser + interpreter

lib/lexer.mll

@@ -0,0 +1,36 @@
+{
+open Lexing
+open Parser
+exception SyntaxError of string
+
+let strip_quotes s = String.sub s 1 (String.length s - 2);;
+}
+
+let digit = ['0'-'9']
+let number_sign = '-' | '+'
+let int = number_sign? digit+
+let double = digit* '.' digit+ | digit+ '.' digit*
+
+
+let white = [' ' '\t']+
+let newline = '\r' | '\n' | "\r\n"
+
+let sym_char = ['a'-'z' 'A'-'Z' '!' '\\' '+' '-' '*' '/' '_' '?']
+let sym = sym_char sym_char*
+
+let str = '"' [^'"']* '"'
+
+rule read =
+    parse
+    | white { read lexbuf }
+    | newline { new_line lexbuf; read lexbuf}
+    | int { INT (int_of_string (Lexing.lexeme lexbuf))}
+    | double { DOUBLE (float_of_string (Lexing.lexeme lexbuf))}
+    | sym { SYM (Lexing.lexeme lexbuf)}
+    | str { STR (strip_quotes (Lexing.lexeme lexbuf))}
+    | '(' { LPAREN }
+    | ')' { RPAREN }
+    | '\'' { QUOTE }
+    | _ { raise (SyntaxError ("Unexpected char: " ^ Lexing.lexeme lexbuf))}
+    | eof { EOF }
+