introducing multiple inheritance

grammars/multiple/City.gf

@@ -0,0 +1,7 @@
+abstract City = {
+  cat 
+    City ;
+  fun
+    MkCity : String -> City ;
+} ;    
+

grammars/multiple/CityEng.gf

@@ -0,0 +1,5 @@
+concrete CityEng of City = open Prelude in {
+  lin
+    MkCity s = s ;
+} ;    
+

grammars/multiple/Math.gf

@@ -0,0 +1,7 @@
+abstract Math = {
+  cat 
+    Number ;
+  fun
+    MkNumber : Int -> Number ;
+} ;    
+

grammars/multiple/MathEng.gf

@@ -0,0 +1,5 @@
+concrete MathEng of Math = open Prelude in {
+  lin
+    MkNumber i = i ;
+} ;    
+

grammars/multiple/System.gf

@@ -0,0 +1,4 @@
+abstract System = {
+  cat Reply ;
+  fun Bye : Reply ;
+}

grammars/multiple/SystemCity.gf

@@ -0,0 +1,4 @@
+abstract SystemCity = System, City ** {
+  fun
+    RDistance : City -> City -> Int -> Reply ;
+} ;

grammars/multiple/SystemCityEng.gf

@@ -0,0 +1,6 @@
+concrete SystemCityEng of SystemCity = SystemEng, CityEng ** open
+  Prelude in {
+  lin
+    RDistance x y d = 
+      ss (["the distance from"] ++ x.s ++ "to" ++ y.s ++ "is" ++ d.s) ;
+} ;

grammars/multiple/SystemEng.gf

@@ -0,0 +1,3 @@
+concrete SystemEng of System = open Prelude in {
+  lin Bye = ss "bye" ;
+}

grammars/multiple/SystemMath.gf

@@ -0,0 +1,4 @@
+abstract SystemMath = System, Math ** {
+  fun
+    RSum : Number -> Number -> Int -> Reply ;
+} ;

grammars/multiple/SystemMathEng.gf

@@ -0,0 +1,6 @@
+concrete SystemMathEng of SystemMath = SystemEng, MathEng ** open
+  Prelude in {
+  lin
+    RSum x y d = 
+      ss (["the sum of"] ++ x.s ++ "and" ++ y.s ++ "is" ++ d.s) ;
+} ;

grammars/multiple/Top.gf

@@ -0,0 +1,7 @@
+abstract Top = User, System ** {
+  cat 
+    Move ;
+  fun
+    MUser : Query -> Move ;
+    MSystem : Reply -> Move ; 
+}

grammars/multiple/TopCity.gf

@@ -0,0 +1 @@
+abstract TopCity = Top, UserCity, SystemCity ** {} ;

grammars/multiple/TopCityEng.gf

@@ -0,0 +1,3 @@
+--# -path=.:../prelude
+
+concrete TopCityEng of TopCity = TopEng, UserCityEng, SystemCityEng ** {} ;

grammars/multiple/TopEng.gf

@@ -0,0 +1,6 @@
+
+concrete TopEng of Top = UserEng, SystemEng ** open Prelude in {
+  lin
+    MUser q = q ;
+    MSystem r = r ;
+}

grammars/multiple/TopMath.gf

@@ -0,0 +1 @@
+abstract TopMath = Top, UserMath, SystemMath ** {} ;

grammars/multiple/TopMathEng.gf

@@ -0,0 +1,3 @@
+--# -path=.:../prelude
+
+concrete TopMathEng of TopMath = TopEng, UserMathEng, SystemMathEng ** {} ;

grammars/multiple/User.gf

@@ -0,0 +1,7 @@
+abstract User = {
+  cat
+    Query ;
+  fun
+    QQuit : Query ;
+} ;
+

grammars/multiple/UserCity.gf

@@ -0,0 +1,5 @@
+abstract UserCity = User, City ** {
+  fun
+    QDistance : City -> City -> Query ;
+} ;
+

grammars/multiple/UserCityEng.gf

@@ -0,0 +1,6 @@
+concrete UserCityEng of UserCity = UserEng, CityEng ** open Prelude in
+  {
+  lin
+    QDistance x y = ss (["what is the distance from"] ++ x.s ++ "to" ++ y.s) ;
+  }
+

grammars/multiple/UserEng.gf

@@ -0,0 +1,5 @@
+concrete UserEng of User = open Prelude in {
+  lin
+    QQuit = ss ["that's enough"] ;
+} ;
+

grammars/multiple/UserMath.gf

@@ -0,0 +1,5 @@
+abstract UserMath = User, Math ** {
+  fun
+    QSum : Number -> Number -> Query ;
+} ;
+

grammars/multiple/UserMathEng.gf

@@ -0,0 +1,6 @@
+concrete UserMathEng of UserMath = UserEng, MathEng ** open Prelude in
+  {
+  lin
+    QSum x y = ss (["what is the sum of"] ++ x.s ++ "and" ++ y.s) ;
+  }
+

grammars/multiple/UserUnionCity.gf

@@ -0,0 +1 @@
+abstract UserUnionCity = union User, City ;

grammars/multiple/map.txt

@@ -0,0 +1,32 @@
+Using multiple inheritance in GF. AR 15/9/2004.
+
+The following diagrams show inheritance between abstract syntaxes in two simple systems.
+
+                   TopCity
+                  /   |    \
+                 /    |     \
+      SystemCity   UserCity  Top
+        /      \   /     \
+  System       City      User
+
+
+                   TopMath
+                  /   |    \
+                 /    |     \
+      SystemMath   UserMath  Top
+        /      \   /     \
+  System       Math      User
+
+
+Idea of each module: 
+
+  User            -- User's moves on any domain
+  System          -- System's moves on any domain
+  Top             -- grammar covering both kinds of moves
+  X = Math, City  -- possible domains
+  UserX           -- User's domain specific moves
+  SystemX         -- System's domain specific moves
+  TopX            -- all moves on the domain X
+
+In parallel to the abstract syntax hierarchies, we have of course
+hierarchies of concrete syntaxes for any language; this directory contains Eng.