sed: Support command lists.

gash/commands/sed.scm

@@ -107,6 +107,8 @@
 
 (define (execute-function function str)
   (match function
+    (('begin . commands)
+     (execute-commands commands str))
     (('s pattern replacement flags)
      (substitute str pattern replacement flags))
     (_ (error "SED: unsupported function" function))))

test/100-sed-command-list.sh

@@ -0,0 +1,4 @@
+input='foo
+bar'
+
+echo "$input" | \sed '/foo/ { s/foo/baz/ s/baz/bar/ } s/bar/baz/'

test/100-sed-command-list.stdout

@@ -0,0 +1,2 @@
+baz
+baz