I think "cheating" is the wrong word. Understanding why and how this works in FriCAS is a very useful exercise. Of course, as you have explained it is moot in a pure statically typed environment like native Aldor (or SPAD if such existed).
On Thu, Jul 28, 2011 at 4:10 PM, Ralf Hemmecke <[email protected]> wrote: > > > On 07/28/2011 09:55 PM, Bill Page wrote: >> Your code: >> >> )abbrev package TF TypeFinder >> TypeFinder(S: Type): with >> GetType: S -> Type >> == add >> GetType(x: S): Type == S >> >> --- >> >> Note: Proper indentation >> >> seems to work fine as a spad package in FriCAS. What problem do you >> see in Aldor? Are you using Aldor standalone or as the library >> compiler for FriCAS? > > Bill, you should know that the session below is cheating. The > interpreter provides the type information for GetType and thus import > TypeFinder with an appropriate S. I am pretty sure that I am right. > > I don't try now, but I am pretty sure that you cannot achieve the things > below directly in SPAD. Of course without importing explicitly from > TypeFinder(Integer) and TypeFinder(Polynomial(Integer)), otherwise it > would be no surprise and, of course, working. > > Ralf > > (1) -> i:Integer := 5 > > (1) 5 > Type: Integer > (2) -> GetType i > > (2) Integer > Type: Type > (3) -> p:Polynomial(Integer) := 7 > > (3) 7 > Type: Polynomial(Integer) > (4) -> GetType p > > (4) Polynomial(Integer) > Type: Type > (5) -> z := 5*x+3 > > (5) 5x + 3 > Type: Polynomial(Integer) > (6) -> GetType z > > (6) Polynomial(Integer) > Type: Type > > -- > You received this message because you are subscribed to the Google Groups > "FriCAS - computer algebra system" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/fricas-devel?hl=en. > > -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/fricas-devel?hl=en.
