> A list is just a space-separate string with quoting rules and the difference is entirely in manipulation.
This has not been true since the release of Tcl 8.0 that added the Tcl_Obj subsystem.
Lists in modern Tcl (8.0+, with 8.0 released in 1997) are proper O(1) indexed arrays. Yes, you can still request from Tcl the 'string' representation of the O(1) indexed array, and the result you get is the old (pre 8.0) "space-separate [sic] string with quoting rules" variant that will parse back into the O(1) indexed array later if you want.
But Tcl lists have not been /only/ those strings for a very long time.
This has not been true since the release of Tcl 8.0 that added the Tcl_Obj subsystem.
Lists in modern Tcl (8.0+, with 8.0 released in 1997) are proper O(1) indexed arrays. Yes, you can still request from Tcl the 'string' representation of the O(1) indexed array, and the result you get is the old (pre 8.0) "space-separate [sic] string with quoting rules" variant that will parse back into the O(1) indexed array later if you want.
But Tcl lists have not been /only/ those strings for a very long time.