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We've seen lists of symbols and lists of numbers; you can of course have a list with elements of any given type...--including other structures like

<tt>

posn

</tt>

_posn_s. This exercise just uses ideas you've already learned, but in new contexts.

1. Define the type of lists of

   HTML
   <tt>

   posn

   HTML
   </tt>

   list of _posn_s.
2. Write the templates of lists of

   HTML
   <tt>

   posn

   HTML
   </tt>

   template for list of posn_s. (NB: There are two non-primitive types here, one inductive the other an inductive type and one that simply consists of a structure. So this writing a program that processes a list of positions may require two templates or one, depending on if you believe in structure templatesusing two templates; a template for lists of _posn_s and a template for processing _posn_s. If you need to use two templates, you _also need to write two functions, one to process a list of positions and one to process positions.)
3. Write the function positive-quadrant? , which takes in a single posn and returns true only when its components are both positive.
4. Develop count-positive-quadrant , which takes a list of

   HTML
   <tt>

   posn

   HTML
   </tt>

   _posn_s and returns a count of those in the upper-right quadrant.
5. Develop filter-positive-quadrant , which takes a list of

   HTML
   <tt>

   posn

   HTML
   </tt>

   _posn_s and returns a list of those in the upper-right quadrant.

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Here are two reasonable definitions for non-empty lists.

• Solution: comp211-lab01.ss (https:wikiriceedudisplayCSWIKI211lab01comp211lab01ss)

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