From: "Cs. Henk" <csaba-ml@...>
Date: 2005-02-28T21:09:29+09:00
Subject: [PATCH] callable argument for PTY.getpty (aka PTY.spawn)

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Hi!

The patch attached enables you to pass a callable object to PTY.spawn,
so that if you do so, of course, the object will be called (instead of
exec'ing an external program).

Rationale: sometimes you want to do some initialization on the pty
before starting the external program, or maybe you don't even want to
call an external program...

Example: this whole thing popped up when I was writing a small readline
wrapper. The pty spawned for the util to be wrapped is to be put into
non-echo mode prior to starting the util. With the current pty the only
way to do this is as follows:

 inp,out,cpid = 
  PTY.spawn(*(["ruby", "-e", 'system "stty -echo"; exec *$*'] + $*))

With this patch I can do just

 inp,out,cpid = PTY.spawn(proc { system "stty -echo"; exec *$*})

Csaba

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diff -Naur ruby-orig/ext/pty/pty.c ruby/ext/pty/pty.c
--- ruby-orig/ext/pty/pty.c	2004-12-08 06:26:27.000000000 -0700
+++ ruby/ext/pty/pty.c	2005-02-28 04:43:11.000000000 -0700
@@ -283,9 +283,14 @@
 	seteuid(getuid());
 #endif
 
-	arg.argc = argc;
-	arg.argv = argv;
-	rb_protect(pty_exec, (VALUE)&arg, &status);
+	if (rb_respond_to(*argv,rb_intern("call"))) {
+	    v = *argv++; 
+	    rb_funcall2(v,rb_intern("call"),--argc,argv);
+	} else {
+	    arg.argc = argc;
+	    arg.argv = argv;
+    	    rb_protect(pty_exec, (VALUE)&arg, &status);
+	}
 	sleep(1);
 	_exit(1);
     }

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