7z: add some TODO notes on parsing "i" output for extensions

Author: scop

completions/7z

@@ -95,6 +95,14 @@ _7z()
     _count_args =
     if [[ $args -eq 2 ]]; then
         _filedir_xspec unzip
+        # TODO: parsing 7z i output?
+        # - how to figure out if the format is input or output?
+        # - find string Formats:, read until next empty line
+        # - extensions start from column 26
+        #   - ignore everything in parens
+        #   - terminate on two spaces
+        #   - terminate on token containing anything [^a-z0-9]
+        #     (assumption: extensions are all lowercase)
         [[ $mode == w ]] &&
             _filedir '@(7z|bz2|swf|?(g)tar|?(t)[bglx]z|tb?(z)2|wim)' ||
             _filedir '@(7z|arj|bz2|cab|chm|cpio|deb|dmg|flv|gem|img|iso|lz[ah]|lzma?(86)|msi|pmd|[rx]ar|rpm|sw[fm]|?(g)tar|taz|?(t)[bglx]z|tb?(z)2|vhd|wim|Z)'