Fix #755 (#757)

* Fix #755

* Add integration test for #755

* Add unit test

examples/inner_expansions.ion

+echo $(let echo_array=[@(echo me myself I)]; echo @echo_array[0] @echo_array[1] @echo_array[2])
+echo $(let echo_array=[@(echo me myself I)]; echo @echo_array[0] @echo_array[2] @echo_array[1])
+echo $(let echo_array=[@(echo me myself I)]; echo @echo_array[1] @echo_array[2] @echo_array[0])
+echo $(let echo_array=[@(echo me myself I)]; echo @echo_array[1] @echo_array[0] @echo_array[2])
+echo $(let echo_array=[@(echo me myself I)]; echo @echo_array[2] @echo_array[1] @echo_array[0])
+echo $(let echo_array=[@(echo me myself I)]; echo @echo_array[2] @echo_array[0] @echo_array[1])

examples/inner_expansions.out

+me myself I
+me I myself
+myself I me
+myself me I
+I myself me
+I me myself

src/lib/parser/shell_expand/words/mod.rs

@@ -254,6 +254,17 @@ impl<'a, E: Expander + 'a> WordIterator<'a, E> {
                 b'"' if !self.flags.contains(Flags::SQUOTE) => self.flags ^= Flags::DQUOTE,
                 b'$' if !self.flags.contains(Flags::SQUOTE) => {
                     if self.data.as_bytes()[self.read + 1] == b'(' {
+                        // Pop out the '(' char
+                        iterator.next();
+                        self.read += 1;
+                        level += 1;
+                    }
+                }
+                b'@' if !self.flags.contains(Flags::SQUOTE) => {
+                    if self.data.as_bytes()[self.read + 1] == b'(' {
+                        // Pop out the '(' char
+                        iterator.next();
+                        self.read += 1;
                         level += 1;
                     }
                 }

src/lib/parser/shell_expand/words/tests.rs

@@ -94,6 +94,22 @@ fn array_processes() {
     compare(input, expected);
 }
 
+#[test]
+fn array_process_within_string_process() {
+    compare(
+        "echo $(let free=[@(free -h)]; echo @free[6]@free[8]/@free[7])",
+        vec![
+            WordToken::Normal("echo", false, false),
+            WordToken::Whitespace(" "),
+            WordToken::Process(
+                "let free=[@(free -h)]; echo @free[6]@free[8]/@free[7]",
+                false,
+                Select::All
+            )
+        ]
+    )
+}
+
 #[test]
 fn indexes() {
     let input = "@array[0..3] @array[0...3] @array[abc] @array[..3] @array[3..]";