xkb: add ComposeTable::feed2 API

compose-tests/src/main.rs

@@ -16,7 +16,7 @@ use {
     thiserror::Error,
 };
 
-// const SINGLE: Option<&str> = Some("t0019");
+// const SINGLE: Option<&str> = Some("t0054");
 const SINGLE: Option<&str> = None;
 const WRITE_MISSING: bool = true;
 const WRITE_FAILED: bool = false;
@@ -76,6 +76,8 @@ enum ResultError {
     WriteActualFailed(#[source] io::Error),
     #[error("could not create compose table")]
     CreateComposeTable,
+    #[error("unknown modifier `{0}`")]
+    UnknownModifier(String),
 }
 
 fn test_case2(diagnostics: &mut Vec<Diagnostic>, case: &Path) -> Result<(), ResultError> {
@@ -115,16 +117,32 @@ fn test_case2(diagnostics: &mut Vec<Diagnostic>, case: &Path) -> Result<(), Resu
         if let Some((pre, _)) = line.split_once("#") {
             line = pre;
         }
-        line = line.trim();
-        if line.is_empty() {
-            continue;
+        let mut iter = line.split_whitespace();
+        match iter.next() {
+            Some(l) => line = l,
+            _ => continue,
+        }
+        let mut accept = None;
+        for modifier in iter {
+            match modifier {
+                "use" => accept = Some(true),
+                "skip" => accept = Some(false),
+                _ => return Err(ResultError::UnknownModifier(modifier.to_string())),
+            }
         }
         let Some(keysym) = Keysym::from_str(line) else {
             return Err(ResultError::UnknownKeysym(line.to_string()));
         };
-        let Some(res) = table.feed(&mut state, keysym) else {
+        let Some(mut out) = table.feed2(&mut state, keysym) else {
             continue;
         };
+        if let Some(accept) = accept {
+            match accept {
+                true => out.use_intermediate_composed(),
+                false => out.skip_intermediate_composed(),
+            }
+        }
+        let res = out.apply();
         match res {
             FeedResult::Pending => actual.push_str("    pending\n"),
             FeedResult::Aborted => actual.push_str("    aborted\n"),

compose-tests/testcases/t00/t005/t0050/XCompose

@@ -0,0 +1,3 @@
+<a> <a>:     A
+<a>:         B
+<a> <a> <a>: C

compose-tests/testcases/t00/t005/t0050/expected.txt

@@ -0,0 +1,7 @@
+a
+    pending
+a
+    pending
+a
+    composed
+        C

compose-tests/testcases/t00/t005/t0050/input.txt

@@ -0,0 +1,3 @@
+a
+a
+a

compose-tests/testcases/t00/t005/t0051/XCompose

@@ -0,0 +1,3 @@
+<a> <a>:     A
+<a> <a> <a>: C
+<a>:         B

compose-tests/testcases/t00/t005/t0051/expected.txt

@@ -0,0 +1,7 @@
+a skip
+    pending
+a
+    pending
+a
+    composed
+        C

compose-tests/testcases/t00/t005/t0051/input.txt

@@ -0,0 +1,3 @@
+a skip
+a
+a

compose-tests/testcases/t00/t005/t0052/XCompose

@@ -0,0 +1,3 @@
+<a> <a> <a>: C
+<a> <a>:     A
+<a>:         B

compose-tests/testcases/t00/t005/t0052/expected.txt

@@ -0,0 +1,9 @@
+a
+    composed
+        B
+
+a skip
+    pending
+a
+    composed
+        A

compose-tests/testcases/t00/t005/t0052/input.txt

@@ -0,0 +1,4 @@
+a
+
+a skip
+a

compose-tests/testcases/t00/t005/t0053/XCompose

@@ -0,0 +1,3 @@
+<a>:         B
+<a> <a>:     A
+<a> <a> <a>: C

compose-tests/testcases/t00/t005/t0053/expected.txt

@@ -0,0 +1,5 @@
+a
+    pending
+a use
+    composed
+        A

compose-tests/testcases/t00/t005/t0053/input.txt

@@ -0,0 +1,2 @@
+a
+a use

compose-tests/testcases/t00/t005/t0054/XCompose

@@ -0,0 +1,3 @@
+<a> <a> <a>: C
+<a> <a>:     A
+<a>:         B

compose-tests/testcases/t00/t005/t0054/expected.txt

@@ -0,0 +1,6 @@
+a
+    composed
+        B
+a
+    composed
+        B

compose-tests/testcases/t00/t005/t0054/input.txt

@@ -0,0 +1,2 @@
+a
+a

compose-tests/testcases/t00/t005/t0055/XCompose

@@ -0,0 +1 @@
+<a>: X

compose-tests/testcases/t00/t005/t0055/expected.txt

@@ -0,0 +1,3 @@
+a skip
+    composed
+        X

compose-tests/testcases/t00/t005/t0055/input.txt

@@ -0,0 +1 @@
+a skip

kbvm/release-notes.md

@@ -74,7 +74,7 @@
 - Added support for `VoidAction()`. This is an alias for
   `LockControls(controls=none, affect=neither)`.
 - In compose files, later productions now always override earlier productions.
-  That is, all of the following are the same:
+  That is, all of the following are the same in the `ComposeTable::feed` API.
 
   ```compose
   <a> <b>:     X
@@ -90,6 +90,10 @@
   <a> <b> <c>: Y
   <a> <b>:     X
   ```
+- A new function `ComposeTable::feed2` has been added to give more control over
+  situations such as the above. In the last example above, after inputting
+  `<a> <b>`, the application can choose to either use the `X` output or proceed
+  to the next possible sequence.
 
 # 0.1.4 (2025-04-21)