Simplified async/await docs

blog/src/AsyncUserInput.lf

@@ -6,44 +6,27 @@ reactor UserInput {
   preamble {=
     #include <stdio.h>
     #include <stdlib.h>
-
-    // Read a line from stdin into dynamically allocated memory, dropping the
-    // trailing newline. The caller must free the result. Returns 0 on EOF or error.
-    size_t read_string(char** result) {
-      char* buffer = NULL;
-      size_t capacity = 0;
-      ssize_t nread = getline(&buffer, &capacity, stdin);
-      if (nread < 0) {
-        free(buffer);
-        return 0;
-      }
-      if (nread > 0 && buffer[nread - 1] == '\n') {
-        buffer[nread - 1] = '\0';
-      }
-      *result = buffer;
-      return nread;
-    }
   =}
   timer t(0, 5 s)
   output out: char*
   state count: int
   physical action awake
 
-  // This reaction must precede the reaction that calls lf_async on the physical action.
-  // It causes that reaction to resume at the logical time of the physical action.
-  reaction(awake) {=
-    lf_async_resume(awake);
-  =}
-
-  reaction(startup) -> out, awake {=
+  reaction(startup, awake) -> out, awake {=
+    lf_print("Control-D to exit.");
     while (true) {
       char* line = NULL;
-      int nread = lf_async(awake, read_string, &line);
-      if (nread == 0) {
+      size_t capacity = 0;
+      int nread = lf_async(awake, getline, &line, &capacity, stdin);
+      if (nread < 0) {
+        lf_print("User input: EOF");
+        free(line);
         lf_request_stop();
         break;
       }
-      // The logical time is now the physical time at which the line was read.
+      if (nread > 0 && line[nread - 1] == '\n') {
+        line[nread - 1] = '\0';
+      }
       lf_set(out, line);
     }
   =}

blog/src/AsyncUserInputPy.lf

@@ -0,0 +1,35 @@
+target Python {
+  keepalive: true
+}
+
+reactor UserInput {
+  timer t(0, 5 s)
+  output out
+  state count = 0
+  physical action awake
+
+  reaction(startup, awake) -> out, awake {=
+    print("Control-D to exit.")
+    while True:
+      try:
+        line = self.lf_async(awake, input)
+        # The logical time is now the physical time at which the line was read.
+        out.set(line)
+      except EOFError:
+        request_stop()
+        break
+  =}
+
+  reaction(t) -> out {=
+    out.set(f"{self.count}: Waiting for input...")
+    self.count += 1
+  =}
+}
+
+main reactor {
+  user_input = new UserInput()
+
+  reaction(user_input.out) {=
+    print(f"At logical time {lf.time.logical_elapsed()}, Line: {user_input.out.value}")
+  =}
+}

blog/src/AwaitLET.lf

@@ -8,13 +8,7 @@ reactor RequestWork {
   timer t(0, 200 ms)
   state count: int = 1
 
-  // This reaction must precede the reaction that awaits the result.
-  // It causes that reaction to resume at the logical time of the result.
-  reaction(result) {=
-    lf_await_resume(result);
-  =}
-
-  reaction(t) result -> request {=
+  reaction(t, result) -> request {=
     lf_print("Request work at logical time " PRINTF_TIME, lf_time_logical_elapsed());
     lf_set(request, self->count++);
     lf_await(result);

blog/src/py/AwaitLET.lf → blog/src/AwaitLETPy.lf

@@ -8,13 +8,7 @@ reactor RequestWork {
   timer t(0, 200 ms)
   state count = 1
 
-  # This reaction must precede the reaction that awaits the result.
-  # It causes that reaction to resume at the logical time of the result.
-  reaction(result) {=
-    self.lf_await_resume(result)
-  =}
-
-  reaction(t) result -> request {=
+  reaction(t, result) -> request {=
     print(f"Request work at logical time {lf.time.logical_elapsed()}")
     request.set(self.count)
     self.count += 1

docs/assets/code/c/src/AsyncUserInput.lf

@@ -29,13 +29,7 @@ reactor UserInput {
   state count: int
   physical action awake
 
-  // This reaction must precede the reaction that calls lf_async on the physical action.
-  // It causes that reaction to resume at the logical time of the physical action.
-  reaction(awake) {=
-    lf_async_resume(awake);
-  =}
-
-  reaction(startup) -> out, awake {=
+  reaction(startup, awake) -> out, awake {=
     while (true) {
       char* line = NULL;
       int nread = lf_async(awake, read_string, &line);

docs/assets/code/c/src/AwaitLET.lf

@@ -8,13 +8,7 @@ reactor RequestWork {
   timer t(0, 200 ms)
   state count: int = 1
 
-  // This reaction must precede the reaction that awaits the result.
-  // It causes that reaction to resume at the logical time of the result.
-  reaction(result) {=
-    lf_await_resume(result);
-  =}
-
-  reaction(t) result -> request {=
+  reaction(t, result) -> request {=
     lf_print("Request work at logical time " PRINTF_TIME, lf_time_logical_elapsed());
     lf_set(request, self->count++);
     lf_await(result);

docs/assets/code/py/src/AsyncUserInput.lf

@@ -17,13 +17,7 @@ reactor UserInput {
   state count = 0
   physical action awake
 
-  # This reaction must precede the reaction that calls lf_async on the physical action.
-  # It causes that reaction to resume at the logical time of the physical action.
-  reaction(awake) {=
-    self.lf_async_resume(awake)
-  =}
-
-  reaction(startup) -> out, awake {=
+  reaction(startup, awake) -> out, awake {=
     while True:
         line = self.lf_async(awake, read_string)
         if line is None:

docs/assets/code/py/src/AwaitLET.lf

@@ -8,13 +8,7 @@ reactor RequestWork {
   timer t(0, 200 ms)
   state count = 1
 
-  # This reaction must precede the reaction that awaits the result.
-  # It causes that reaction to resume at the logical time of the result.
-  reaction(result) {=
-    self.lf_await_resume(result)
-  =}
-
-  reaction(t) result -> request {=
+  reaction(t, result) -> request {=
     print(f"Request work at logical time {lf.time.logical_elapsed()}")
     request.set(self.count)
     self.count += 1