Re: How to implement dynamic typing?

"BGB / cr88192" <cr88192@hotmail.com> wrote in message
> "David Belier" <davidbleier@hotmail.com> wrote in message
>> Recently I finished chapter 7 of the dragon book (2nd edition) but I
>> still don't understand how to implement dynamic typing. I don't get
>> how you are supposed to store the type information with each variable
>> and check it every time using an acceptable amount of resources and
>> time. Can someone please name papers or websites to read?
>
> as others have said, it is not stored with the variable.


Yes, quite a few people have said that.


Yet, I *do* store a tag with the variable! So clearly I must be doing
something wrong...


In:


  A := (1, "two", 3.0)


a tag is stored with the variable A (saying it is a list), but tags are also
stored for each of the values (saying they are an integer, a string, and a
float).


(In this implementation, A is not a pointer, it is a descriptor containing,
for this example, the list tag, the length of the list (3), and a pointer to
the elements, each in turn being a descriptor.)


So more accurately tags can be stored with both variables and values.


--
Bartc

Return to the comp.compilers page.
Search the comp.compilers archives again.