September Morn Update

Task/Multiple-distinct-objects/00META.yaml

@@ -0,0 +1 @@
+--- {}

Task/Multiple-distinct-objects/ALGOL-W/multiple-distinct-objects.alg

@@ -0,0 +1,24 @@
+begin
+    record    T  ( integer n, m );
+    reference(T) singleT;
+    integer      numberOfElements;
+    singleT          := T( 0, 0 );
+    numberOfElements := 3;
+    begin
+        reference(T) array tArray ( 1 :: numberOfElements );
+        % initialise the "right" way            %
+        for i := 1 until numberOfElements do begin
+            tArray( i )    := T( i, i * 2 );
+            m(tArray( i )) := m(tArray( i )) + 1;
+        end for_i ;
+        write();
+        for i := 1 until numberOfElements do writeon( i_w := 1, s_w := 0, n(tArray( i )), ", ", m(tArray( i )), "; " );
+        % initialise the "wrong" way            %
+        for i := 1 until numberOfElements do begin
+            tArray( i )    := singleT;
+            m(tArray( i )) := m(tArray( i )) + 1;
+        end for_i ;
+        write();
+        for i := 1 until numberOfElements do writeon( i_w := 1, s_w := 0, n(tArray( i )), ", ", m(tArray( i )), "; " )
+    end
+end.

Task/Multiple-distinct-objects/Modula-3/multiple-distinct-objects-1.mod3

@@ -0,0 +1 @@
+VAR a: ARRAY[1..N] OF T

Task/Multiple-distinct-objects/Modula-3/multiple-distinct-objects-2.mod3

@@ -0,0 +1,56 @@
+MODULE DistinctObjects EXPORTS Main;
+
+IMPORT IO, Random;
+
+VAR
+
+  random := NEW(Random.Default).init();
+
+TYPE
+
+  T = RECORD (* value will initialize to 2 unless otherwise specified *)
+    value: INTEGER := 2;
+  END;
+
+CONST Size = 3;
+
+VAR
+
+  (* initialize records *)
+  t1 := T { 3 };
+  t2 := T { 4 };
+  t3 :  T;       (* t3's value will be default (2) *)
+
+  (* initialize a reference to T with value 100 *)
+  tr := NEW(REF T, value := 100);
+
+  (* initialize an array of records *)
+  a := ARRAY[1..Size] OF T { t1, t2, t3 };
+  (* initialize an array of integers *)
+  b := ARRAY[1..Size] OF INTEGER { -9, 2, 6 };
+  (* initialize an array of references to a record -- NOT copied! *)
+  c := ARRAY[1..Size] OF REF T { tr, tr, tr };
+
+BEGIN
+
+  (* display the data *)
+  FOR i := 1 TO Size DO
+    IO.PutInt(a[i].value); IO.Put(" , ");
+    IO.PutInt(b[i]);       IO.Put(" , ");
+    IO.PutInt(c[i].value); IO.Put(" ; ");
+  END;
+  IO.PutChar('\n');
+
+  (* re-initialize a's data to random integers *)
+  FOR i := 1 TO Size DO a[i].value := random.integer(-10, 10); END;
+  (* modify "one" element of c *)
+  c[1].value := 0;
+  (* display the data *)
+  FOR i := 1 TO Size DO
+    IO.PutInt(a[i].value); IO.Put(" , ");
+    IO.PutInt(b[i]);       IO.Put(" , ");
+    IO.PutInt(c[i].value); IO.Put(" ; ");
+  END;
+  IO.PutChar('\n');
+
+END DistinctObjects.

Task/Multiple-distinct-objects/Modula-3/multiple-distinct-objects.mod3

@@ -1 +0,0 @@
-VAR a: ARRAY OF T

Task/Multiple-distinct-objects/Rust/multiple-distinct-objects.rust

@@ -0,0 +1,21 @@
+use std::rc::Rc;
+use std::cell::RefCell;
+
+fn main() {
+    let size = 3;
+
+    // Clone the given element to fill out the vector.
+    let mut v: Vec<String> = vec![String::new(); size];
+    v[0].push('a');
+    println!("{:?}", v);
+
+    // Run a given closure to create each element.
+    let mut v: Vec<String> = (0..size).map(|i| i.to_string()).collect();
+    v[0].push('a');
+    println!("{:?}", v);
+
+    // For multiple mutable views of the same thing, use something like Rc and RefCell.
+    let v: Vec<Rc<RefCell<String>>> = vec![Rc::new(RefCell::new(String::new())); size];
+    v[0].borrow_mut().push('a');
+    println!("{:?}", v);
+}