gh-107: Fix TNS slice assignment.

Author: python-processing-unit

src/interpreter.c

@@ -2188,6 +2188,8 @@ ExecResult assign_index_chain(Interpreter* interp, Env* env, Expr* idx_expr, Val
         return make_error("Out of memory", stmt_line, stmt_col);
     }
 
+    bool rhs_applied_directly = false;
+
     walker = idx_expr;
     for (size_t i = 0; i < chain_len; i++) {
         nodes[i] = walker;
@@ -2393,6 +2395,7 @@ ExecResult assign_index_chain(Interpreter* interp, Env* env, Expr* idx_expr, Val
             free(starts); free(ends); free(orig_to_out);
             // After slice assignment, set cur to base (no further chaining into this node)
             cur = &base_val;
+            rhs_applied_directly = true;
             continue;
         }
 
@@ -2457,14 +2460,16 @@ ExecResult assign_index_chain(Interpreter* interp, Env* env, Expr* idx_expr, Val
     }
 
     // If we get here, the chain ended after resolving to a tensor element (e.g. a<1> = rhs)
-    if (cur->type != VAL_NULL && value_type_to_decl(cur->type) != value_type_to_decl(rhs.type)) {
-        out = make_error("Element type mismatch", stmt_line, stmt_col);
-        goto cleanup;
+    if (!rhs_applied_directly) {
+        if (cur->type != VAL_NULL && value_type_to_decl(cur->type) != value_type_to_decl(rhs.type)) {
+            out = make_error("Element type mismatch", stmt_line, stmt_col);
+            goto cleanup;
+        }
+        mtx_lock(&g_tns_lock);
+        value_free(*cur);
+        *cur = value_copy(rhs);
+        mtx_unlock(&g_tns_lock);
     }
-    mtx_lock(&g_tns_lock);
-    value_free(*cur);
-    *cur = value_copy(rhs);
-    mtx_unlock(&g_tns_lock);
 
     out = make_ok(value_null());
 

tests/test2.pre

@@ -109,6 +109,18 @@ ASSERT(NOT(ISTNS(0d5)))
 DEL(t)
 PRINT("Tensors: PASS\n")
 
+PRINT("Testing slice indexing...")
+TNS: t = [0d1, 0d2, 0d3]
+t[0d1-0d2] = [0d4, 0d5]
+ASSERT(EQ(t, [0d4, 0d5, 0d3]))
+ASSERT(EQ(t[0d1-0d2], [0d4, 0d5]))
+ASSERT(EQ(t[0d1--0d1], [0d4, 0d5, 0d3]))
+t[*] = [0d6, 0d7, 0d8]
+ASSERT(EQ(t, [0d6, 0d7, 0d8]))
+ASSERT(EQ(t[*], [0d6, 0d7, 0d8]))
+DEL(t)
+PRINT("Slice indexing: PASS\n")
+
 PRINT("Testing PAUSE/RESUME/PAUSED...")
 ! Use a deterministic handshake: worker sets `pause_started` and
 ! waits for `pause_go` to be set. Main waits for `pause_started`, then