Parser: audio statements (play / start_music / stop_music)

The \`play\`, \`start_music\`, and \`stop_music\` keywords were lexed
but not parsed. Programs using them failed with a generic "unexpected
token" error. Now:

- \`Statement::Play(sfx_name, span)\`
- \`Statement::StartMusic(track_name, span)\`
- \`Statement::StopMusic(span)\`

parse successfully and flow through analyzer / IR lowering / codegen
as no-ops. Semantics match the spec but produce no output — no audio
driver exists yet. Users who need sound can still wire in custom
code via \`asm { ... }\` blocks.

https://claude.ai/code/session_01W6eQFStA66EuMKHUFo2rx3

src/analyzer/mod.rs

@@ -974,6 +974,11 @@ impl Analyzer {
                 // codegen parses and validates the body; analysis has
                 // nothing to check.
             }
+            Statement::Play(_, _) | Statement::StartMusic(_, _) | Statement::StopMusic(_) => {
+                // Audio statements are parsed and recognized but
+                // currently generate no code — no audio driver exists.
+                // Users who need audio can use inline `asm` blocks.
+            }
         }
     }
 
@@ -1219,7 +1224,10 @@ fn collect_calls_stmt(stmt: &Statement, calls: &mut Vec<String>) {
         | Statement::Continue(_)
         | Statement::LoadBackground(_, _)
         | Statement::SetPalette(_, _)
-        | Statement::InlineAsm(_, _) => {}
+        | Statement::InlineAsm(_, _)
+        | Statement::Play(_, _)
+        | Statement::StartMusic(_, _)
+        | Statement::StopMusic(_) => {}
     }
 }
 

src/codegen/mod.rs

@@ -370,6 +370,9 @@ impl CodeGen {
                     self.emit(BRK, AM::Implied);
                 }
             },
+            Statement::Play(_, _) | Statement::StartMusic(_, _) | Statement::StopMusic(_) => {
+                // Audio statements compile to no-ops for now.
+            }
         }
     }
 

src/ir/lowering.rs

@@ -344,6 +344,10 @@ impl LoweringContext {
             Statement::InlineAsm(body, _) => {
                 self.emit(IrOp::InlineAsm(body.clone()));
             }
+            Statement::Play(_, _) | Statement::StartMusic(_, _) | Statement::StopMusic(_) => {
+                // No audio driver yet — these parse but produce no
+                // IR.
+            }
         }
     }
 

src/parser/ast.rs

@@ -286,6 +286,15 @@ pub enum Statement {
     /// Inline 6502 assembly captured verbatim. The body is parsed by
     /// the codegen stage using `asm::parse_inline`.
     InlineAsm(String, Span),
+    /// Audio: `play SfxName` — trigger a one-shot sound effect.
+    /// Currently a no-op at codegen time; no audio driver exists.
+    Play(String, Span),
+    /// Audio: `start_music TrackName` — begin playing background music.
+    /// Currently a no-op at codegen time.
+    StartMusic(String, Span),
+    /// Audio: `stop_music` — stop any currently-playing music.
+    /// Currently a no-op at codegen time.
+    StopMusic(Span),
 }
 
 impl Statement {
@@ -308,7 +317,10 @@ impl Statement {
             | Self::Scroll(_, _, s)
             | Self::DebugLog(_, s)
             | Self::DebugAssert(_, s)
-            | Self::InlineAsm(_, s) => *s,
+            | Self::InlineAsm(_, s)
+            | Self::Play(_, s)
+            | Self::StartMusic(_, s)
+            | Self::StopMusic(s) => *s,
         }
     }
 }

src/parser/mod.rs

@@ -899,6 +899,23 @@ impl Parser {
                 Ok(Statement::Scroll(x, y, span))
             }
             TokenKind::KwDebug => self.parse_debug_statement(),
+            TokenKind::KwPlay => {
+                let span = self.current_span();
+                self.advance();
+                let (name, _) = self.expect_ident()?;
+                Ok(Statement::Play(name, span))
+            }
+            TokenKind::KwStartMusic => {
+                let span = self.current_span();
+                self.advance();
+                let (name, _) = self.expect_ident()?;
+                Ok(Statement::StartMusic(name, span))
+            }
+            TokenKind::KwStopMusic => {
+                let span = self.current_span();
+                self.advance();
+                Ok(Statement::StopMusic(span))
+            }
             TokenKind::KwAsm => {
                 let span = self.current_span();
                 self.advance(); // KwAsm

src/parser/tests.rs

@@ -665,6 +665,27 @@ fn parse_mmc3_mapper() {
     assert_eq!(prog.game.mapper, Mapper::MMC3);
 }
 
+#[test]
+fn parse_audio_statements() {
+    let src = r#"
+        game "Audio" { mapper: NROM }
+        on frame {
+            play JumpSfx
+            start_music MainTheme
+            stop_music
+        }
+        start Main
+    "#;
+    let prog = parse_ok(src);
+    let frame = prog.states[0].on_frame.as_ref().unwrap();
+    assert!(matches!(frame.statements[0], Statement::Play(ref n, _) if n == "JumpSfx"));
+    assert!(matches!(
+        frame.statements[1],
+        Statement::StartMusic(ref n, _) if n == "MainTheme"
+    ));
+    assert!(matches!(frame.statements[2], Statement::StopMusic(_)));
+}
+
 #[test]
 fn parse_struct_decl() {
     let src = r#"