Typol facilities

[kuehne@pi.informatik.th-darmstadt.de (Thomas Kuehne)]

First i would like to suggest a useful extension of the TYPOL typechecker.
There should be (maybe on&off switchable) WARNINGS for TYPOL variables
used only once in a TYPOL rule. If the single occurence was intentional
use of the anonymous variable is appropiate. In the case of a misspelled
variable name (that is the single ocurrence happened by accident) it would
be most helpful to get a hint from the typechecker. Currently one wonders
why things go wrong during execution, simply because some unification did not
take place that should have (If one spelled the variables correctly).

^C
(Interrupt -- one more to kill letter)
^Cpisun19% mail centaur@mirsa.inria.fr
Subject: Typol facilities

First i would like to suggest a useful extension of the TYPOL typechecker.
There should be (maybe on&off switchable) WARNINGS for TYPOL variables
used only once in a TYPOL rule. If the single occurence was intentional
use of the anonymous variable is appropiate. In the case of a misspelled
variable name (that is the single ocurrence happened by accident) it would
be most helpful to get a hint from the typechecker. Currently one wonders
why things go wrong during execution, simply because some unification did not
take place that should have (If the variable name were spelled correctly).

Am i right to assume that, using TYPOL, there is no way walking up some tree,
without walking down before ?
Say i want to start at some leaf in a tree, working way up to the root, while
modifying the path from root to leaf.
The possibility i can think of is to start at the root, walking to all leafs
and returning new subtrees for each subtree in the tree.
The result of the calculation, which will be the old tree in most of the
subtrees, will replace the old tree.
Is there another more fitting solution for my aim?
If you want to reply on this matter please consider that if i have to
start at the root i do not want to use additional information to navigate
to the goal-leaf.

Thank you

	- Thomas -