toolcontext: add `usage` and `tooldescription`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/toolcontext.nit b/src/toolcontext.nit
index ba080e3..b91fdad 100644 (file)
--- a/src/toolcontext.nit
+++ b/src/toolcontext.nit
@@ -171,6 +171,22 @@ class ToolContext
                option_context.add_option(opt_warn, opt_quiet, opt_stop_on_first_error, opt_no_color, opt_log, opt_log_dir, opt_help, opt_version, opt_verbose)
        end
 
+       # Name, usage and synopsis of the tool.
+       # It is mainly used in `usage`.
+       # Should be correctly set by the client before calling `process_options`
+       # A multi-line string is recommmended.
+       #
+       # eg. `"Usage: tool [OPTION]... [FILE]...\nDo some things."`
+       var tooldescription: String writable = "Usage: [OPTION]... [ARG]..."
+
+       # print the full usage of the tool.
+       # It also could be called by the client.
+       fun usage
+       do
+               print tooldescription
+               option_context.usage
+       end
+
        # Parse and process the options given on the command line
        fun process_options
        do