TCL does for quite some years now use real integers (unbounded size) and floats (float8) whenever possible. By the way, the article does not specify versions of

TCL does for quite some years now use real integers (unbounded size) and floats (float8) whenever possible. By the way, the article does not specify versions of languages, so: $ tclsh % puts $tcl_version 8.6 % expr "9999999999999999.0-9999999999999998.0" 2.0