feat(parser): add ON trigger and TRIGGER PROCEDURE statement parsing

CLAUDE.md

@@ -96,14 +96,14 @@ Defines AST nodes for the parser. Key types:
 Parses ABL source code into an AST. Key capabilities:
 
 - **Expression parsing** with proper operator precedence (ternary → or → and → comparison → additive → multiplicative → unary → postfix → primary)
-- **Statement parsing**: DEFINE VARIABLE/VAR/PARAMETER/TEMP-TABLE/BUFFER/PROPERTY/STREAM/FRAME/EVENT, DO blocks (with counting loops), IF/THEN/ELSE, REPEAT, FOR EACH, FIND, CASE, PROCEDURE, FUNCTION, RUN, DISPLAY (with STREAM clause), MESSAGE, ASSIGN, CREATE, DELETE, RELEASE, VALIDATE, BUFFER-COPY, BUFFER-COMPARE, INPUT/OUTPUT/INPUT-OUTPUT stream I/O (FROM/TO/THROUGH/CLOSE), CATCH/FINALLY/THROW, PUBLISH/SUBSCRIBE/UNSUBSCRIBE, LEAVE, NEXT, RETURN
+- **Statement parsing**: DEFINE VARIABLE/VAR/PARAMETER/TEMP-TABLE/BUFFER/PROPERTY/STREAM/FRAME/EVENT, DO blocks (with counting loops), IF/THEN/ELSE, REPEAT, FOR EACH, FIND, CASE, PROCEDURE, FUNCTION, RUN, DISPLAY (with STREAM clause), MESSAGE, ASSIGN, CREATE, DELETE, RELEASE, VALIDATE, BUFFER-COPY, BUFFER-COMPARE, INPUT/OUTPUT/INPUT-OUTPUT stream I/O (FROM/TO/THROUGH/CLOSE), CATCH/FINALLY/THROW, PUBLISH/SUBSCRIBE/UNSUBSCRIBE, ON (UI/developer event triggers with IN FRAME/IN BROWSE, database event triggers, key remapping), TRIGGER PROCEDURE, LEAVE, NEXT, RETURN
 - **OO-ABL**: CLASS (with ABSTRACT/FINAL, INHERITS, IMPLEMENTS), INTERFACE, METHOD (with access modifiers, STATIC/ABSTRACT/OVERRIDE), DEFINE PROPERTY (auto and computed GET/SET), CONSTRUCTOR, DESTRUCTOR, USING
 - **Postfix operations**: Method calls (object:method()), member access (object.member), array access (arr[i]), field access (table.field)
 - **Function calls** with argument lists
 - **Preprocessor**: &IF/&ELSEIF/&ELSE/&ENDIF at statement, expression, and data type levels via generic `PreprocIf<T>`, &SCOPED-DEFINE/&GLOBAL-DEFINE with `PreprocEnd` lexer token, &UNDEFINE, &MESSAGE, `{&variable}` references
 - **Error recovery** via `parse_program()` with synchronization on period boundaries
 
-Not yet implemented: ON triggers.
+Not yet implemented: DO/FOR/REPEAT block-header ON phrases (ON ERROR UNDO, ON ENDKEY UNDO).
 
 ### Code Generation (`oxabl_codegen`)
 
@@ -170,4 +170,4 @@ cargo bench -p oxabl_common --bench source_map_bench
 - `oxabl_lexer`: MVP complete with 43 tests
 - `oxabl_common/source_map`: Implemented with 10 tests
 - `oxabl_ast`: Implemented with expressions, statements, and data types
-- `oxabl_parser`: Actively developed with 330 tests; parses expressions, control flow, variable declarations, functions, procedures, temp-tables, error handling, OO-ABL (CLASS, METHOD, PROPERTY, INTERFACE), preprocessor directives, stream I/O, and frame definitions
+- `oxabl_parser`: Actively developed with 406 tests; parses expressions, control flow, variable declarations, functions, procedures, temp-tables, error handling, OO-ABL (CLASS, METHOD, PROPERTY, INTERFACE), preprocessor directives, stream I/O, frame definitions, ON triggers (UI events, database events, key remapping), and TRIGGER PROCEDURE

crates/oxabl_ast/src/statement.rs

@@ -509,6 +509,36 @@ pub enum Statement {
         operation: StreamOperation,
     },
 
+    /// ON trigger statement -- event handlers for UI, database, and key events.
+    ///
+    /// ```abl
+    /// ON CHOOSE OF btnOk IN FRAME f1 DO: /* ... */ END.
+    /// ON WRITE OF Customer NEW BUFFER bNew OLD BUFFER bOld DO: /* ... */ END.
+    /// ON F1 HELP.
+    /// ```
+    On { kind: OnKind },
+
+    /// TRIGGER PROCEDURE FOR event OF table [NEW/OLD clauses].
+    ///
+    /// Declares a schema trigger -- always the first statement in a trigger procedure file.
+    ///
+    /// ```abl
+    /// TRIGGER PROCEDURE FOR WRITE OF Customer
+    ///     NEW BUFFER bNew OLD BUFFER bOld.
+    /// ```
+    TriggerProcedure {
+        /// The trigger event (CREATE, DELETE, FIND, WRITE, ASSIGN, or REPLICATION-*).
+        event: DbTriggerEvent,
+        /// The target table (or table.field for ASSIGN OF form).
+        target: Identifier,
+        /// NEW/OLD BUFFER referencing (WRITE triggers).
+        referencing: TriggerReferencing,
+        /// NEW VALUE variable definition (ASSIGN triggers, mutually exclusive with OF form).
+        new_value: Option<TriggerAssignParam>,
+        /// OLD VALUE variable definition (ASSIGN NEW VALUE form).
+        old_value_param: Option<TriggerAssignParam>,
+    },
+
     /// Leave statement - exit innermost loop
     Leave,
 
@@ -865,3 +895,127 @@ pub enum SubscribeTarget {
     /// Subscribe to events from any publisher.
     Anywhere,
 }
+
+// =============================================================================
+// ON trigger types
+// =============================================================================
+
+/// Discriminant for the different forms of the ON statement.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum OnKind {
+    /// UI/developer event trigger (includes "WEB-NOTIFY" ANYWHERE form):
+    /// ON event-list OF widget-list [OR event-list OF widget-list]... [ANYWHERE]
+    ///   { trigger-block | REVERT | PERSISTENT RUN proc [(args)] }
+    UiEvent {
+        /// Event/widget clauses -- at least one, chained via OR.
+        /// Empty when ANYWHERE is used standalone (e.g., ON "WEB-NOTIFY" ANYWHERE).
+        clauses: Vec<OnEventClause>,
+        /// Whether ANYWHERE was specified.
+        anywhere: bool,
+        /// The trigger action.
+        action: OnAction,
+    },
+    /// Database event trigger:
+    /// ON CREATE|DELETE|FIND|WRITE|ASSIGN OF table [referencing] [OVERRIDE]
+    ///   { trigger-block | REVERT }
+    DbEvent {
+        /// The database event.
+        event: DbTriggerEvent,
+        /// The table (or table.field for ASSIGN) the trigger is on.
+        target: Identifier,
+        /// NEW/OLD BUFFER/VALUE referencing phrases.
+        referencing: TriggerReferencing,
+        /// Whether OVERRIDE was specified.
+        is_override: bool,
+        /// The trigger action (block or REVERT).
+        action: OnAction,
+    },
+    /// Key remapping: ON key-label key-function.
+    KeyRemap {
+        /// The key label (e.g., F1, CTRL-X) -- any identifier.
+        key_label: Identifier,
+        /// The key function (e.g., HELP, ENDKEY, GO) -- any identifier.
+        key_function: Identifier,
+    },
+}
+
+/// A single event/widget-list clause in a UI ON trigger.
+///
+/// `ON CHOOSE, ENTRY OF btnOk IN FRAME f1, btnCancel`
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct OnEventClause {
+    /// Comma-separated event names (identifiers, including keywords like LEAVE/ENTRY).
+    pub events: Vec<Identifier>,
+    /// Comma-separated widget references with optional frame/browse qualifiers.
+    pub widgets: Vec<WidgetRef>,
+}
+
+/// The action taken by an ON trigger.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum OnAction {
+    /// A trigger block -- either a single statement or DO...END block.
+    Block(Box<Statement>),
+    /// REVERT -- removes the trigger.
+    Revert,
+    /// PERSISTENT RUN procedure [(args)].
+    PersistentRun {
+        procedure: Identifier,
+        arguments: Vec<Expression>,
+    },
+}
+
+/// Database trigger event types.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum DbTriggerEvent {
+    Create,
+    Delete,
+    Find,
+    Write,
+    Assign,
+    ReplicationCreate,
+    ReplicationDelete,
+    ReplicationWrite,
+}
+
+/// Referencing phrase for database triggers (NEW/OLD BUFFER for WRITE, OLD VALUE for ASSIGN).
+/// Shared between ON db-event triggers and TRIGGER PROCEDURE.
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct TriggerReferencing {
+    /// NEW [BUFFER] alias (WRITE triggers).
+    pub new_buffer: Option<Identifier>,
+    /// OLD [BUFFER] alias (WRITE triggers).
+    pub old_buffer: Option<Identifier>,
+    /// OLD [VALUE] alias (ASSIGN triggers in ON statement).
+    pub old_value: Option<Identifier>,
+}
+
+/// Widget reference in an ON trigger, with optional frame/browse qualifier.
+///
+/// `btnOk IN FRAME main-frame` or `col1 IN BROWSE brw1`
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct WidgetRef {
+    pub name: Identifier,
+    pub qualifier: Option<WidgetQualifier>,
+}
+
+/// Optional qualification for a widget reference.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum WidgetQualifier {
+    /// IN FRAME frame-name
+    InFrame(Identifier),
+    /// IN BROWSE browse-name
+    InBrowse(Identifier),
+}
+
+/// A variable-like parameter for TRIGGER PROCEDURE FOR ASSIGN NEW VALUE form.
+///
+/// ```abl
+/// TRIGGER PROCEDURE FOR ASSIGN
+///     NEW VALUE newVal AS CHARACTER
+///     OLD VALUE oldVal AS CHARACTER.
+/// ```
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct TriggerAssignParam {
+    pub name: Identifier,
+    pub data_type: DataType,
+}

crates/oxabl_lexer/build.rs

@@ -93,6 +93,7 @@ fn main() {
             "blank",
             "blob",
             "break",
+            "browse",
             "buffer",
             "buffer-compare",
             "buffer-copy",
@@ -111,6 +112,7 @@ fn main() {
             "char",
             "character",
             "check",
+            "choose",
             "chr",
             "class",
             "clear",
@@ -203,6 +205,7 @@ fn main() {
             "enable",
             "encode",
             "end",
+            "endkey",
             "entry",
             "eq",
             "error stat",

crates/oxabl_lexer/src/kind.rs

@@ -323,6 +323,9 @@ pub enum Kind {
     Event,
     Signature,
     RunProcedure,
+    Choose,
+    Endkey,
+    Browse,
 
     // Phrases
     Editing,
@@ -832,11 +835,13 @@ pub fn match_keyword(s: &str) -> Option<Kind> {
             "availa" => Some(Kind::Available),
             "backgr" => Some(Kind::Background),
             "begins" => Some(Kind::Begins),
+            "browse" => Some(Kind::Browse),
             "buffer" => Some(Kind::Buffer),
             "can do" => Some(Kind::CanDo),
             "can-do" => Some(Kind::CanDo),
             "center" => Some(Kind::Centered),
             "charac" => Some(Kind::Character),
+            "choose" => Some(Kind::Choose),
             "create" => Some(Kind::Create),
             "cursor" => Some(Kind::Cursor),
             "dbname" => Some(Kind::Dbname),
@@ -852,6 +857,7 @@ pub fn match_keyword(s: &str) -> Option<Kind> {
             "displa" => Some(Kind::Display),
             "enable" => Some(Kind::Enable),
             "encode" => Some(Kind::Encode),
+            "endkey" => Some(Kind::Endkey),
             "escape" => Some(Kind::Escape),
             "except" => Some(Kind::Except),
             "exists" => Some(Kind::Exists),

crates/oxabl_parser/src/parser/mod.rs

@@ -279,6 +279,14 @@ impl<'a> Parser<'a> {
                     | Kind::Event
                     | Kind::Signature
                     | Kind::RunProcedure
+                    // ON trigger keywords (unreserved)
+                    | Kind::Trigger
+                    | Kind::Triggers
+                    | Kind::Persistent
+                    | Kind::Revert
+                    | Kind::Choose
+                    | Kind::Endkey
+                    | Kind::Browse
             )
     }