Re: [9front] Re: /bin/"" use of rc -c instead of eval

[Romano <me+unobe@fallglow.com>]

On Sat Jul  6 07:11:12 -0700 2024, sirjofri+ml-9front@sirjofri.de wrote:
> To add on that, I would vote for changing everything to make cd work. It's about consistency.
> 
> The question is if it's better to have it in /bin/"" or as /env/fn#"". I think that /bin/"" makes more sense for various reasons.
> 
> Also a good question would be: do we create an extra case for cd commands, or do we use eval? An extra case for cd commands would imply that the cd part of custom programs (including shell scripts) wouldn't work, so eval would be the most consistent, as OP suggested. I don't know about the downsides of eval though.
 
I noticed there was a bigger issue with rc, and so sent the mailing list
a suggested patch to address. With that in place, the below patch makes
"" works for built-ins by defining itself as a function, which then
updates the parent since it's called with a shared environment.

From: Romano <me+unobe@fallglow.com>
Date: Thu, 11 Jul 2024 05:56:24 +0000
Subject: [PATCH] make "" use a fn that will then work with built-ins

	currently "" does not work with built-ins, so re-running
	built-ins might not have the desired effect (e.g., setting
	environment variables, cd). This updates "" to be defined
	internally as a function, which then updates the parent
	environment after being called.
---
diff 23b40c5aa93bb205423c8c40d02eef825011b215 7637f8f5fd6490d07ba64bcf404321028e698ed9
--- a/rc/bin/""
+++ b/rc/bin/""
@@ -1,5 +1,5 @@
-#!/bin/rc
-
+#!/bin/rc -b
+fn "" {
 PROMPT='[^ 	]*(%|;)+[ 	]+'
 
 _x = `{" $* | tail -1}
@@ -10,4 +10,6 @@
 
 echo '	' $_x >[1=2]
 _x=`{ echo -n 'eval '''; echo $_x | sed 's/^'$PROMPT'//; s/''/''''/g; s/$/''/'}
-rc -c $"_x
+eval $"_x
+}
+"" $*