synchronization

spl/std.spl

@@ -905,3 +905,20 @@ func register-field { | with field-name namespace-name ;
     iter:next dyn-call
     iter:foreach<&dyn-objcall>
 }
+
+
+construct Synchronizer {
+    sync
+    ;
+    construct { this | with this ;
+        0 this:=sync
+        this
+    }
+    do { | with callable this ;
+        "will increment the sync field if and only if it is zero. when it was incremented (returned zero), the loop will exit";
+        while { this "sync" atomic-get-inc-if-zero } { yield }
+        callable:call
+        0 this:=sync
+    }
+}
+

src/std_fns.rs

@@ -1014,6 +1014,11 @@ pub fn time(stack: &mut Stack) -> OError {
     Ok(())
 }
 
+pub fn thread_yield(stack: &mut Stack) -> OError {
+    thread::yield_now();
+    Ok(())
+}
+
 pub fn str_readf(stack: &mut Stack) -> OError {
     require_on_stack!(string, Str, stack, "str-readf");
     require_on_stack!(pat, Str, stack, "str-readf");
@@ -1275,9 +1280,22 @@ pub fn json_parse(stack: &mut Stack) -> OError {
     Ok(())
 }
 
+pub fn atomic_get_inc_if_zero(stack: &mut Stack) -> OError {
+    require_on_stack!(field, Str, stack, "atomic-get-inc-if-zero");
+    let o = stack.pop();
+    let o = o.lock_ro();
+    let f = o.field(&field, stack)?;
+    let mut f = f.lock();
+    stack.push(f.clone().spl());
+    if f.native == Value::Mega(0) {
+        f.native = Value::Mega(1);
+    }
+    Ok(())
+}
+
 pub fn register(r: &mut Stack, o: Arc<Frame>) {
     type Fn = fn(&mut Stack) -> OError;
-    let fns: [(&str, Fn, u32); 71] = [
+    let fns: [(&str, Fn, u32); 73] = [
         ("pop", pop, 0),
         ("dup", dup, 2),
         ("dup2", dup2, 3),
@@ -1340,6 +1358,7 @@ pub fn register(r: &mut Stack, o: Arc<Frame>) {
         ("write-file-sasm", write_file_sasm, 1),
         ("fork", fork, 0),
         ("sleeptime", time, 0),
+        ("yield", thread_yield, 0),
         ("str-readf", str_readf, 1),
         ("str-to-mega-radix", str_to_mega_radix, 1),
         ("mega-to-str-radix", mega_to_str_radix, 1),
@@ -1349,6 +1368,7 @@ pub fn register(r: &mut Stack, o: Arc<Frame>) {
         ("delete-file", delete_file, 1),
         ("delete-dir", delete_dir, 1),
         ("chdir", chdir, 0),
+        ("atomic-get-inc-if-zero", atomic_get_inc_if_zero, 1),
         // ("json-parse", json_parse, 1),
     ];
     for f in fns {

test.spl

@@ -464,6 +464,34 @@ func main { int | with args ;
         println
     }
 
+    
+    "" println;
+    "testing sync (should be 5)" println;
+
+    def x 5 =x
+    def sync Synchronizer:new =sync
+
+    10 :foreach<|
+        fork<| 10 :foreach<| sync:do<| x ++ =x > > >
+        fork<| 10 :foreach<| sync:do<| x -- =x > > >
+    >
+
+    1000 time:sleep;
+
+    x println
+
+    "nonsynced for comparison:" println
+
+    def x 5 =x
+
+    10 :foreach<|
+        fork<| 10 :foreach<| x ++ =x > >
+        fork<| 10 :foreach<| x -- =x > >
+    >
+
+    1000 time:sleep;
+
+    x println