PR#5159: better documentation of type "position"

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@12144 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

1 files changed, 5 insertions, 2 deletions

diff --git a/stdlib/lexing.mli b/stdlib/lexing.mli
index 6008e127b..2591b5c18 100644
--- a/stdlib/lexing.mli
+++ b/stdlib/lexing.mli
@@ -26,9 +26,12 @@ type position = {
 (** A value of type [position] describes a point in a source file.
    [pos_fname] is the file name; [pos_lnum] is the line number;
    [pos_bol] is the offset of the beginning of the line (number
-   of characters between the beginning of the file and the beginning
+   of characters between the beginning of the lexbuf and the beginning
    of the line); [pos_cnum] is the offset of the position (number of
-   characters between the beginning of the file and the position).
+   characters between the beginning of the lexbuf and the position).
+   The difference between [pos_cnum] and [pos_bol] is the character
+   offset within the line (i.e. the column number, assuming each
+   character is one column wide).
 
    See the documentation of type [lexbuf] for information about
    how the lexing engine will manage positions.