Add new `functions` flag -V/--inherit-variable

--inherit-variable takes a variable name and snapshots its current
value. When the function is executed, it will have a local variable with
this value already defined. Printing the function source will include
synthesized `set -l` lines for the values.

This is primarily useful for functions that are created on the fly, such
as in `psub`.

1 files changed, 32 insertions, 0 deletions

diff --git a/tests/function.in b/tests/function.in
new file mode 100644
index 00000000..e533b25b
--- /dev/null
+++ b/tests/function.in
@@ -0,0 +1,32 @@
+# vim: set filetype=fish:
+#
+# Test the `function` builtin
+
+# utility function
+function show_ary -a name --no-scope-shadowing
+    set -l count (count $$name)
+    echo "\$$name: ($count)"
+    if test $count -gt 0
+        for i in (seq $count)
+            echo "$i: '$$name[1][$i]'"
+        end
+    end
+end
+
+# Test the -V flag
+set -g foo 'global foo'
+set -l foo 'local foo'
+set bar one 'two    2' \t '' 3
+set baz
+function frob -V foo -V bar -V baz
+    show_ary foo
+    show_ary bar
+    show_ary baz
+end
+echo "Testing -V"
+frob
+echo "Testing -V with changed variables"
+set foo 'bad foo'
+set bar 'bad bar'
+set baz 'bad baz'
+frob