1 files changed, 225 insertions, 0 deletions
diff --git a/src/mml_composemusic_mcp/semantic_base.py b/src/mml_composemusic_mcp/semantic_base.py
new file mode 100644
index 0000000..0318a84
--- /dev/null
+++ b/src/mml_composemusic_mcp/semantic_base.py
@@ -0,0 +1,225 @@
+"""Base semantic analyzer: AST -> NoteSequence IR."""
+
+from dataclasses import dataclass, field
+
+from .ast_nodes import (
+    ASTNode,
+    BarStmt,
+    DetuneStmt,
+    DutyStmt,
+    EnvelopeDefStmt,
+    ExtCmdStmt,
+    GateTimeStmt,
+    LengthStmt,
+    NoteStmt,
+    OctaveStmt,
+    Program,
+    RepeatEndStmt,
+    RepeatStartStmt,
+    RestStmt,
+    Statement,
+    TempoStmt,
+    TieStmt,
+    Track,
+    TransposeStmt,
+    VolumeStmt,
+)
+from .ir import (
+    ErrorCode,
+    ErrorDetail,
+    ErrorPhase,
+    NoteEvent,
+    NoteSequence,
+    RestEvent,
+)
+from .parser_base import length_value_to_ticks
+
+
+@dataclass
+class SemanticContext:
+    errors: list[ErrorDetail] = field(default_factory=list)
+
+    def add_error(
+        self,
+        code: ErrorCode,
+        line: int,
+        column: int,
+        message: str,
+        severity: str,
+        hint: str = "",
+        context: str = "",
+    ) -> None:
+        self.errors.append(
+            ErrorDetail(
+                code=code,
+                phase=ErrorPhase.SEMANTIC,
+                line=line,
+                column=column,
+                message=message,
+                severity=severity,
+                hint=hint,
+                context=context,
+            )
+        )
+
+
+class SemanticAnalyzer:
+    """Base class for converting AST to NoteSequence IR."""
+
+    def __init__(self, source: str, program: Program) -> None:
+        self.source = source
+        self.program = program
+        self.ctx = SemanticContext()
+        self.note_sequence = NoteSequence()
+        self.current_channel: str | None = None
+        self.octave = 4
+        self.default_length = 4
+        self.velocity = 15
+        self.gate_time = 1.0
+        self.duty = 2
+        self.tick_position = 0
+
+    def analyze(self) -> tuple[NoteSequence, list[ErrorDetail]]:
+        for track in self.program.tracks:
+            self._analyze_track(track)
+        self._finalize()
+        return self.note_sequence, self.ctx.errors
+
+    def _analyze_track(self, track: Track) -> None:
+        self.current_channel = track.channel
+        self._reset_state(track)
+        if track.channel == "Loop":
+            self._handle_loop_track(track)
+            return
+        for stmt in track.statements:
+            self._analyze_statement(stmt)
+
+    def _reset_state(self, track: Track) -> None:
+        self.octave = 4
+        self.default_length = 4
+        self.velocity = 15
+        self.gate_time = 1.0
+        self.duty = 2
+        self.tick_position = 0
+
+    def _handle_loop_track(self, track: Track) -> None:
+        # Loop track is handled after all tracks are processed.
+        pass
+
+    def _finalize(self) -> None:
+        for ch in self.note_sequence.channels.values():
+            ch.total_ticks = max(
+                (e.tick_position + getattr(e, "duration", 0) for e in ch.events),
+                default=0,
+            )
+
+    def _analyze_statement(self, stmt: Statement) -> None:
+        if isinstance(stmt, NoteStmt):
+            self._analyze_note(stmt)
+        elif isinstance(stmt, RestStmt):
+            self._analyze_rest(stmt)
+        elif isinstance(stmt, OctaveStmt):
+            self._analyze_octave(stmt)
+        elif isinstance(stmt, LengthStmt):
+            self._analyze_length(stmt)
+        elif isinstance(stmt, VolumeStmt):
+            self._analyze_volume(stmt)
+        elif isinstance(stmt, DutyStmt):
+            self._analyze_duty(stmt)
+        elif isinstance(stmt, TempoStmt):
+            self._analyze_tempo(stmt)
+        elif isinstance(stmt, GateTimeStmt):
+            self._analyze_gate_time(stmt)
+        elif isinstance(stmt, TransposeStmt):
+            self._analyze_transpose(stmt)
+        elif isinstance(stmt, DetuneStmt):
+            self._analyze_detune(stmt)
+        elif isinstance(stmt, TieStmt):
+            self._analyze_tie(stmt)
+        elif isinstance(stmt, RepeatStartStmt):
+            self._analyze_repeat_start(stmt)
+        elif isinstance(stmt, RepeatEndStmt):
+            self._analyze_repeat_end(stmt)
+        elif isinstance(stmt, BarStmt):
+            pass
+        elif isinstance(stmt, ExtCmdStmt):
+            self._analyze_ext_cmd(stmt)
+        elif isinstance(stmt, EnvelopeDefStmt):
+            self._analyze_stage2(stmt)
+        else:
+            self._analyze_stage2(stmt)
+
+    def _ticks_for(self, stmt: NoteStmt | RestStmt) -> int:
+        length = stmt.length if stmt.length is not None else self.default_length
+        return length_value_to_ticks(length, stmt.dots)
+
+    def _analyze_note(self, stmt: NoteStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_rest(self, stmt: RestStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_octave(self, stmt: OctaveStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_length(self, stmt: LengthStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_volume(self, stmt: VolumeStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_duty(self, stmt: DutyStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_tempo(self, stmt: TempoStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_gate_time(self, stmt: GateTimeStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_tie(self, stmt: TieStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_repeat_start(self, stmt: RepeatStartStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_repeat_end(self, stmt: RepeatEndStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_ext_cmd(self, stmt: ExtCmdStmt) -> None:
+        raise NotImplementedError
+
+    def _analyze_stage2(self, stmt: ASTNode) -> None:
+        self.ctx.add_error(
+            code=ErrorCode.SEMANTIC_UNSUPPORTED_FEATURE,
+            line=stmt.line,
+            column=stmt.column,
+            message=f"'{stmt.__class__.__name__}' は第2段階で実装されます。",
+            severity="warning",
+            hint="現時点では無視されます。",
+            context=self._context_line(stmt),
+        )
+
+    def _add_event(self, event) -> None:  # type: ignore[no-untyped-def]
+        ch = self.note_sequence.channels[self.current_channel]  # type: ignore[index]
+        ch.events.append(event)
+
+    def _last_note_end(self) -> int:
+        ch = self.note_sequence.channels[self.current_channel]  # type: ignore[index]
+        for ev in reversed(ch.events):
+            if isinstance(ev, (NoteEvent, RestEvent)):
+                return ev.tick_position + ev.duration
+        return self.tick_position
+
+    def _extend_last_note(self, ticks: int) -> None:
+        ch = self.note_sequence.channels[self.current_channel]  # type: ignore[index]
+        for ev in reversed(ch.events):
+            if isinstance(ev, (NoteEvent, RestEvent)):
+                ev.duration += ticks
+                return
+
+    def _context_line(self, node: ASTNode) -> str:
+        lines = self.source.splitlines()
+        if 1 <= node.line <= len(lines):
+            return lines[node.line - 1]
+        return ""