Discuss the default behaviour up front before talking about options

modifying it; based on a remark by kristaps@.
While here, mention parsing of unformatted files
and the changed index format and fix a few minor issues.

1 files changed, 47 insertions, 36 deletions

diff --git a/mandocdb.8 b/mandocdb.8
index e7a0bf13..f2feba5e 100644
--- a/mandocdb.8
+++ b/mandocdb.8
@@ -23,7 +23,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl av
-.Op Ar dir...
+.Op Ar dir ...
 .Nm
 .Op Fl v
 .Fl d Ar dir
@@ -43,52 +43,54 @@ and
 .Sx Index Database
 for fast retrieval.
 .Pp
-The arguments are as follows:
-.Bl -tag -width Ds
-.It Fl a
-Use all directories and files found below
-.Ar dir ... .
-By default, only files matching
+By default,
+.Nm
+creates databases in each
+.Ar dir
+using the files
 .Sm off
 .Sy man Ar section Li /
 .Op Ar arch Li /
 .Ar title . section
 .Sm on
-will be used.
+and
+.Sm off
+.Sy cat Ar section Li /
+.Op Ar arch Li /
+.Ar title . Sy 0
+.Sm on
+in that directory;
+existing databases are truncated.
+If
+.Ar dir
+is not provided,
+.Nm
+uses the default paths stipulated by
+.Xr man 1 .
+.Pp
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl a
+Use all directories and files found below
+.Ar dir ... .
 .It Fl d Ar dir
 Merge (remove and re-add)
 .Ar
-from the databases in
-.Ar dir .
+to the database in
+.Ar dir
+without truncating it.
 .It Fl u Ar dir
 Remove
 .Ar
-from the databases in
-.Ar dir .
-.It Ar dir...
-Recursively add files rooted at each
+from the database in
 .Ar dir
-to the databases in the respective
-.Ar dir .
-Existing databases are truncated.
+without truncating it.
 .It Fl v
 Verbose operation.
 Use once to display all files added or removed and twice for keywords as
 well.
 .El
 .Pp
-By default,
-.Nm
-creates databases in each
-.Ar dir
-using files rooted in that directory.
-If
-.Ar dir
-is not provided,
-.Nm
-uses the default paths stipulated by
-.Xr man 1 .
-.Pp
 If fatal parse errors are encountered while parsing, the offending file
 is printed to stderr, omitted from the index, and the parse continues
 with the next input file.
@@ -101,18 +103,27 @@ database with record values consisting of
 .Pp
 .Bl -enum -compact
 .It
-a nil-terminated filename,
+the string
+.Cm mdoc ,
+.Cm man ,
+or
+.Cm cat
+to indicate the file type,
 .It
-a nil-terminated manual section,
+the filename,
 .It
-a nil-terminated manual title,
+the manual section,
 .It
-a nil-terminated architecture
-.Pq this is not often available
+the manual title,
 .It
-and a nil-terminated description.
+the architecture
+.Pq often empty ,
+.It
+and the description.
 .El
 .Pp
+Each of the above is NUL-terminated.
+.Pp
 Both the manual section and description may be zero-length if the record
 is unassigned.
 Entries are sequentially-numbered, but the filenames are unordered.
@@ -121,7 +132,7 @@ The keyword database,
 .Pa mandoc.db ,
 is a
 .Xr btree 3
-database of nil-terminated keywords (record length is non-zero string
+database of NUL-terminated keywords (record length is non-zero string
 length plus one) mapping to a 8-byte binary field consisting of the
 keyword type and source
 .Sx Index Database