Merge pull request #61 from marcusramberg/improve_help

Better help for perl6 binary

src/Perl6/Compiler.nqp

@@ -41,4 +41,35 @@ class Perl6::Compiler is HLL::Compiler {
             }
         }
     }
+
+    method usage($name?) {
+        say(($name ?? $name !! "") ~ " [switches] [--] [programfile] [arguments]
+ 
+        With no arguments, enters a REPL. With a \"[programfile]\" or the
+        \"-e\" option, compiles the given program and by default also
+        executes the compiled code.
+ 
+          -c                   check syntax only (runs BEGIN and CHECK blocks)
+          --doc                extract documentation and print it as text
+          -e program           one line of program
+          -h, --help           display this help text
+          -n                   run program once for each line of input
+          -p                   same as -n, but also print \$_ at the end of lines
+          --target=[stage]     specify compilation stage to emit
+          -t, --trace=[flags]  enable trace flags, see 'parrot --help-debug'
+          --encoding=[mode]    specify string encoding mode
+          -o, --output=[name]  specify name of output file
+          -v, --version        display version information
+          --stagestats         display time spent in the compilation stages
+          --ll-backtrace       display a low level backtrace on errors
+
+        Note that only boolean single-letter options may be bundled.
+
+        To modify the include path, you can set the PERL6LIB environment variable:
+        
+        PERL6LIB=\"lib\" perl6 example.pl
+        
+        For more information, see the perl6(1) man page.\n"); 
+        pir::exit__vi(0);
+    }
 }