Add basic `defer` implementation.

We don't have any closures yet, so it's essentially the same as just
moving the statement after the `defer` keyword to the end of the block/
right before returning from the function.

2 files changed, 64 insertions, 1 deletions

diff --git a/tests/common.sh b/tests/common.sh
index 1047708..965975c 100644
--- a/tests/common.sh
+++ b/tests/common.sh
@@ -57,7 +57,7 @@ function assert_stdout_text() {
         echo "----------------------------------------------" 
         echo "Test failed: executable returned non-0 code"
         echo "----------------------------------------------"
-        echo "$code"
+        echo "$1"
         exit 1
     fi
     if [[ "$output" != $2 ]]
diff --git a/tests/basics.sh b/tests/core.sh
index fc43847..71c539d 100755
--- a/tests/basics.sh
+++ b/tests/core.sh
@@ -123,4 +123,67 @@ fn main() {
     return x + y - 1;  
 }
 EOF
+echo " OK"
+
+echo -n "- Defer: "
+assert_stdout_text \
+"fn main() {
+    defer print(5);
+    print(4);
+}" \
+"4
+5"
+
+assert_stdout_text \
+"fn main() {
+    defer print(1);
+    {
+        defer print(2);
+        {
+            defer print(3);
+            print(4);
+        }
+        print(5);
+        return 0;
+    }
+    print(10);
+}" \
+"4
+3
+5
+2
+1"
+
+assert_stdout_text \
+"fn test() {
+    defer {
+        defer print(1);
+        print(2);
+    }
+    print(3);
+}
+fn main() {
+    defer print(4);
+    defer test();
+    print(10);
+}" \
+"10
+3
+2
+1
+4"
+
+assert_stdout_text \
+"let g: int;
+fn test(): int {
+    g = 5;
+    defer g = 10;
+    return g;
+}
+fn main() {
+    print(test());
+    print(g);
+}" \
+"5
+10"
 echo " OK"
\ No newline at end of file