Subtle stuff.
Thanks, everyone, for your patience. You've been VERY helpful. Great list!
Michael
--- On Sat, 7/31/10, Brandon S Allbery KF8NH
Are you saying:
[ head x ] -> [ *thunk* ] and length [ *thunk* ] -> 1, independent of what *thunk* is, even head [], i.e., *thunk* never needs be evaluated?
Exactly. (I was being cagey because the first response was cagey, possibly suspecting a homework question although it seems like an odd time for it.) length not only does not look inside of the thunk, it *can't* look inside it; all it knows is that it has a list, it specifically does *not* know what that list can hold. So the only thing it can do is count the number of "unknown somethings" in the list. - -- brandon s. allbery [linux,solaris,freebsd,perl] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkxUa54ACgkQIn7hlCsL25XVpgCeIxWwVWhjYQQ86uE2JeJD7mCB mKUAn3WwhrgrYyudv/E8pn5a0HB4gLA9 =H++/ -----END PGP SIGNATURE----- _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe