lrec tutorial examples

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diff --git a/examples/lrec-tutorial/Morpho.gf b/examples/lrec-tutorial/Morpho.gf
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+resource Morpho = open Prelude in {
+
+param
+  VForm = VInf | VPres | VPast | VPastPart | VPresPart ;
+
+oper
+  Verb : Type = {s : VForm => Str} ;
+
+-- worst-case function for data abstraction
+
+  mkVerb : (_,_,_,_,_ : Str) -> Verb = \vi,vpr,vpa,vpap,vprp -> {
+    s = table {
+      VInf => vi ;
+      VPres => vpr ;
+      VPast => vpa ;
+      VPastPart => vpap ;
+      VPresPart => vprp
+      }
+    } ;
+
+  regVerb : Str -> Verb = \walk -> 
+    mkVerb walk (walk + "s") (walk + "ed") (walk + "ed") (walk + "ing") ;
+
+  s_regVerb : Str -> Verb = \kiss -> 
+    mkVerb kiss (kiss + "es") (kiss + "ed") (kiss + "ed") (kiss + "ing") ;
+
+  e_regVerb : Str -> Verb = \use -> 
+    let us = init use 
+    in
+    mkVerb use (use + "s") (us + "ed") (us + "ed") (us + "ing") ;
+
+  y_regVerb : Str -> Verb = \cry -> 
+    let cr = init cry 
+    in
+    mkVerb cry (cr + "ies") (cr + "ied") (cr + "ied") (cry + "ing") ;
+
+  ie_regVerb : Str -> Verb = \die -> 
+    let dy = Predef.tk 2 die + "y" 
+    in
+    mkVerb die (die + "s") (die + "d") (die + "d") (dy + "ing") ;
+
+  dupRegVerb : Str -> Verb = \stop -> 
+    let stopp = stop + last stop 
+    in
+    mkVerb stop (stop + "s") (stopp + "ed") (stopp + "ed") (stopp + "ing") ;
+
+  smartVerb : Str -> Verb = \v -> case v of {
+    _ + ("s"|"z"|"x"|"ch")      => s_regVerb v ;
+    _                    + "ie" => ie_regVerb v ;
+    _                    + "ee" => mkVerb v (v + "s") (v + "d") (v + "d") (v + "ing") ;
+    _                     + "e" => e_regVerb v ;
+    _ + ("a"|"e"|"o"|"u") + "y" =>   regVerb v ;
+    _                     + "y" => y_regVerb v ;
+    _ + ("ea"|"ee"|"ie"|"oa"|"oo"|"ou") + ? => regVerb v ;
+    _ + ("a"|"e"|"i"|"o"|"u") + 
+            ("b"|"d"|"g"|"m"|"n"|"p"|"s"|"t") => dupRegVerb v ;
+    _ => regVerb v
+    } ;
+
+  irregVerb : (_,_,_ : Str) -> Verb = \sing,sang,sung -> 
+    let v = smartVerb sing 
+    in
+    mkVerb sing (v.s ! VPres) sang sung (v.s ! VPresPart) ;
+
+-- first example of matching
+
+  add_s : Str -> Str = \v -> case v of {
+    _ +     ("s"|"z"|"x"|"ch")  => v  + "es" ;
+    _ + ("a"|"e"|"o"|"u") + "y" => v  + "s" ;
+    cr                    + "y" => cr + "ies" ;
+    _                           => v  + "s"
+    } ;
+
+-- user paradigm
+
+  mkV = overload {
+    mkV : (cry : Str) -> Verb = smartVerb ;
+    mkV : (sing,sang,sung : Str) -> Verb = irregVerb ;
+    mkV : (go,goes,went,gone,going : Str) -> Verb = mkVerb ;
+  } ;
+
+}