Ken,<br><br>Thanks for the references! Have two-level types been applied to parser generation?<br><br>Best wishes,<br><br>--greg<br><br><blockquote style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;" class="gmail_quote">
Greg Meredith <<a href="mailto:lgreg.meredith@biosimilarity.com" target="_blank">lgreg.meredith@biosimilarity.com</a>> wrote in article <<a href="mailto:5de3f5ca0712111100l79ec280fl1d828b12125abbdc@mail.gmail.com" target="_blank">
5de3f5ca0712111100l79ec280fl1d828b12125abbdc@mail.gmail.com
</a>> in gmane.comp.lang.haskell.cafe:<br>> Here is an idea so obvious that someone else must have already thought of it<br>> and worked it all out. Consider the following grammar.<br><br>Hello!<br><br>If I understand your basic idea correctly, it is to split a recursive
<br>data type into two parts, a non-recursive type constructor and a<br>knot-tying recursive type. This idea has been christened "two-level<br>types" by<br><br> Tim Sheard and Emir Pasalic. 2004. Two-level types and
<br> parameterized modules. Journal of Functional Programming<br> 14(5):547-587.<br><br>The idea dates earlier, to initial-algebra semantics and "functional<br>programming with bananas and lenses":<br><br>
Mark P. Jones. 1995. Functional programming with overloading and<br> higher-order polymorphism. In Advanced functional programming:<br> 1st international spring school on advanced functional programming<br> techniques, ed. Johan Jeuring and Erik Meijer, 97-136. Lecture
<br> Notes in Computer Science 925.<br> <a href="http://web.cecs.pdx.edu/%7Empj/pubs/springschool.html" target="_blank">http://web.cecs.pdx.edu/~mpj/pubs/springschool.html</a><br><br> Erik Meijer, Maarten Fokkinga, and Ross Paterson. 1991. Functional
<br> programming with bananas, lenses, envelopes and barbed wire. In<br> Functional programming languages and computer architecture: 5th<br> conference, ed. John Hughes, 124-144. Lecture Notes in Computer<br> Science 523.
<br> <a href="http://research.microsoft.com/%7Eemeijer/Papers/fpca91.pdf" target="_blank">http://research.microsoft.com/~emeijer/Papers/fpca91.pdf</a><br><br>Cheers,<br> Ken<br></blockquote><br>Best wishes,<br>
<br>
--greg<br clear="all"><br>-- <br>L.G. Meredith<br>Managing Partner<br>Biosimilarity LLC<br>505 N 72nd St<br>Seattle, WA 98103<br><br>+1 206.650.3740<br><br><a href="http://biosimilarity.blogspot.com">http://biosimilarity.blogspot.com
</a>