Update hw4 to a newer version.

Signed-off-by: jmug <u.g.a.mariano@gmail.com>

hw4/lib/util/range.mli

@@ -0,0 +1,53 @@
+(* Ranges and utilities on ranges. *)
+
+(* A range represents a segment of text in a given file; it has a
+ * beginning and ending position specified in terms of line and column
+ * numbers. A range is associated with tokens during lexing to allow
+ * the compiler to give better error messages during lexing and
+ * parsing.  
+ *)
+
+(* a position in the source file; line number and column *)
+type pos = int * int
+
+(* a range of positions in a particular file *)
+type t = string * pos * pos
+
+(* line of position *)
+val line_of_pos : pos -> int
+
+(* column of position *)
+val col_of_pos : pos -> int
+
+(* new position with given line and col *)
+val mk_pos : int -> int -> pos
+
+(* the filename a range is in *)
+val file_of_range : t -> string
+
+(* the beginning of the range *)
+val start_of_range : t -> pos
+
+(* the end of the range *)
+val end_of_range : t -> pos
+
+(* create a new range from the given filename and start, end positions *)
+val mk_range : string -> pos -> pos -> t
+
+(* merge two ranges together *)
+val merge_range : t -> t -> t
+
+(* pretty-print a range *)
+val string_of_range : t -> string
+
+(* print a range as an ocaml value *)
+val ml_string_of_range : t -> string
+
+(* use to tag generated AST nodes where range does not apply *)
+val norange : t
+
+val pos_of_lexpos : Lexing.position -> pos
+
+val mk_lex_range : Lexing.position -> Lexing.position -> t
+
+val lex_range : Lexing.lexbuf -> t