Rob Thorpe wrote: > Andreas Rossberg wrote: >>Rob Thorpe wrote: >> >>>Its easy to create a reasonable framework. >> >>Luca Cardelli has given the most convincing one in his seminal tutorial >>"Type Systems", where he identifies "typed" and "safe" as two orthogonal >>dimensions and gives the following matrix: >> >> | typed | untyped >> -------+-------+---------- >> safe | ML | Lisp >> unsafe | C | Assembler >> >>Now, jargon "dynamically typed" is simply untyped safe, while "weakly >>typed" is typed unsafe. > > Consider a langauge something like BCPL or a fancy assembler, but with > not quite a 1:1 mapping with machine langauge. > > It differs in one key regard: it has a variable declaration command. > This command allows the programmer to allocate a block of memory to a > variable. If the programmer attempts to index a variable outside the > block of memory allocated to it an error will occur. Similarly if the > programmer attempts to copy a larger block into a smaller block an > error would occur. > > Such a language would be truly untyped and "safe", that is safe > according to many peoples use of the word including, I think, yours. > > But it differs from latently typed languages like python, perl or lisp. > In such a language there is no information about the type the variable > stores. The programmer cannot write code to test it, and so can't > write functions that issue errors if given arguments of the wrong type.
So the hypothetical language, unlike Python, Perl and Lisp, is not dynamically *tagged*. -- David Hopwood <[EMAIL PROTECTED]> -- http://mail.python.org/mailman/listinfo/python-list
