Does anyone know a standard package for tcl to easily parse the input arguments ? or a ready proc ? ( I have only 3 flags but something general is preferable ).

回答1:

The documentation includes an example. Here is a simple example:

package require cmdline

set parameters {
    {server.arg ""   "Which server to search"}
    {debug           "Turn on debugging, default=off"}
}

set usage "- A simple script to demo cmdline parsing"
array set options [cmdline::getoptions ::argv $parameters $usage]
parray options

Sample runs:

$ tclsh simple.tcl 
options(debug)  = 0
options(server) = 

$ tclsh simple.tcl -server google.com
options(debug)  = 0
options(server) = google.com

$ tclsh simple.tcl -server google.com -debug
options(debug)  = 1
options(server) = google.com

$ tclsh simple.tcl -help
simple - A simple script to demo cmdline parsing
 -server value        Which server to search <>
 -debug               Turn on debugging, default=off
 -help                Print this message
 -?                   Print this message

    while executing
"error [usage $optlist $usage]"
    (procedure "cmdline::getoptions" line 15)
    invoked from within
"cmdline::getoptions ::argv $parameters $usage"
    invoked from within
"array set options [cmdline::getoptions ::argv $parameters $usage]"
    (file "simple.tcl" line 11)

Discussion

Unlike most Linux utilities, TCL uses single dash instead of double dashes for command-line options
When a flags ends with .arg, then that flag expects an argument to follow, such as in the case of server.arg
The debug flag does not end with .arg, therefore it does not expect any argument
The user defines the command-line parameters by a list of lists. Each sub-list contains 2 or 3 parts:
- The flag (e.g. debug)
- The default value (e.g. 0), only if the parameter takes an argument (flag ends with .arg).
- And the help message
Invoke usage/help with -help or -?, however, the output is not pretty, see the last sample run.

Update: Help/Usage

I have been thinking about the message output when the user invoke help (see the last sample run above). To get around that, you need to trap the error yourself:

set usage "- A simple script to demo cmdline parsing"
if {[catch {array set options [cmdline::getoptions ::argv $parameters $usage]}]} {
    puts [cmdline::usage $parameters $usage]
} else {
    parray options
}

Sample run 2:

$ tclsh simple.tcl -?
simple - A simple script to demo cmdline parsing
 -server value        Which server to search <>
 -debug               Turn on debugging, default=off
 -help                Print this message
 -?                   Print this message

回答2:

Tcllib has such a package, cmdline. It's a bit underdocumented, but it works.