1 files changed, 36 insertions, 12 deletions
diff --git a/blackboard2gradebook.tcl b/blackboard2gradebook.tcl
index 81e2be4..5bce8e2 100755
--- a/blackboard2gradebook.tcl
+++ b/blackboard2gradebook.tcl
@@ -4,15 +4,50 @@
 exec tclsh "$0" "$@"
 
 package require Tcl 8.5
+package require try         ;# Tcllib.
+package require cmdline 1.5 ;# First version with proper error-codes.
 package require json::write
 package require sqlite3
 package require md5
 source ./GradeBook_lib.tcl
 
-################# Config ############################################
+set options {
+	{w          "Write to database, disabled by default"}
+}
+set usage "
+Usage:
+  $argv0 \[options] gradebook.sqlitedb blackboard.sqlitedb
+
+  Expect both DB files to be sqilte tables.
+  Exported DB should have a single table 'export_table'
+
+Example:
+  $argv0  2020_Fall_Phys251 blackboard.db
+
+Options:"
+
+try {
+	array set params [::cmdline::getoptions argv $options $usage]
+	#parray params
+
+	# Note: argv is modified now. The recognized options are
+	# removed from it, leaving the non-option arguments behind.
+	if { [llength $argv] < 2 } {
+		throw {CMDLINE USAGE} [::cmdline::usage $options $usage]
+	}
+} trap {CMDLINE USAGE} {msg o} {
+	# Trap the usage signal, print the message, and exit the application.
+	# Note: Other errors are not caught and passed through to higher levels!
+	puts $msg
+	exit 1
+}
+
 # if DRYRUN is true the database will not be modified
 set DRYRUN true
+set DRYRUN [expr {!$params(w)}]
+
 
+################# Config ############################################
 #set categories2export [list FinalExam HomeWork LabReport]
 set categories2export [list FinalExam]
 
@@ -22,17 +57,6 @@ set infoColumsMarkers {{ - Lateness \(H:M:S\)} { - Max Points} { - Submission Ti
 set skipCreationCol [concat $commonInfoCol $infoColumsMarkers]
 ######################################################################
 
-if { $argc < 2 } {	
-	puts {Usage:}
-	puts "  $argv0 gradebook.sqlitedb blackboard.sqlitedb"
-	puts {}
-	puts {  expect both files to be sqilte tables:}
-	puts {  blackboard should have a single table 'export_table':}
-	puts {Example:}
-	puts [concat "  $argv0" { 2020_Fall_Phys251 blackboard.db}]
-	exit
-}
-
 set classDB [lindex $argv 0] 
 set blackboardDB [lindex $argv 1]