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path: root/src/mml_composemusic_mcp/lexer.py
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-rw-r--r--src/mml_composemusic_mcp/lexer.py314
1 files changed, 314 insertions, 0 deletions
diff --git a/src/mml_composemusic_mcp/lexer.py b/src/mml_composemusic_mcp/lexer.py
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+++ b/src/mml_composemusic_mcp/lexer.py
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+"""Common lexer for MML."""
+
+from collections.abc import Iterable
+from dataclasses import dataclass
+from enum import Enum, auto
+
+
+class TokenType(Enum):
+ NOTE = auto()
+ REST = auto()
+ OCTAVE = auto()
+ OCTAVE_UP = auto()
+ OCTAVE_DOWN = auto()
+ LENGTH = auto()
+ VOLUME = auto()
+ DUTY = auto()
+ TEMPO = auto()
+ GATE_TIME = auto()
+ TIE = auto()
+ REPEAT_START = auto()
+ REPEAT_END = auto()
+ BAR = auto()
+ TRACK_HEADER = auto()
+ HEADER = auto()
+ COMMENT = auto()
+ NUMBER = auto()
+ SHARP = auto()
+ FLAT = auto()
+ DOT = auto()
+ TEXT = auto()
+ AT = auto()
+ TRANSPOSE = auto()
+ DETUNE = auto()
+ EXT_CMD = auto() # @ENV, @VIB, @GLI
+ EOF = auto()
+
+
+@dataclass
+class Token:
+ type: TokenType
+ value: str
+ line: int
+ column: int
+ raw: str = ""
+
+
+def _track_header_char(ch: str) -> bool:
+ return ch.isupper() and ch in "ABTNL"
+
+
+class Lexer:
+ def __init__(self, source: str, mode: str = "ppmck") -> None:
+ self.source = source
+ self.mode = mode.lower()
+ self.tokens: list[Token] = []
+ self.line = 1
+ self.column = 1
+ self.pos = 0
+
+ def _peek(self, offset: int = 0) -> str:
+ idx = self.pos + offset
+ if idx >= len(self.source):
+ return ""
+ return self.source[idx]
+
+ def _advance(self) -> str:
+ ch = self.source[self.pos]
+ self.pos += 1
+ if ch == "\n":
+ self.line += 1
+ self.column = 1
+ else:
+ self.column += 1
+ return ch
+
+ def _skip_whitespace(self) -> None:
+ while self.pos < len(self.source) and self.source[self.pos] in " \t\r":
+ self._advance()
+
+ def _read_number(self) -> str:
+ start = ""
+ while self.pos < len(self.source) and self.source[self.pos].isdigit():
+ start += self._advance()
+ return start
+
+ def _read_until_newline(self) -> str:
+ start = ""
+ while self.pos < len(self.source) and self.source[self.pos] not in "\r\n":
+ start += self._advance()
+ return start
+
+ def _read_header_value(self) -> str:
+ value = ""
+ if self._peek() == '"':
+ self._advance()
+ while self.pos < len(self.source) and self._peek() not in '"\r\n':
+ value += self._advance()
+ if self._peek() == '"':
+ self._advance()
+ else:
+ # Return raw unterminated header; parser reports error
+ pass
+ return value
+
+ def tokenize(self) -> list[Token]:
+ while self.pos < len(self.source):
+ self._skip_whitespace()
+ if self.pos >= len(self.source):
+ break
+ ch = self._peek()
+ start_line = self.line
+ start_col = self.column
+
+ if self.mode == "ppmck":
+ self._tokenize_ppmck(ch, start_line, start_col)
+ else:
+ self._tokenize_pyxel(ch, start_line, start_col)
+ self.tokens.append(Token(TokenType.EOF, "", self.line, self.column))
+ return self.tokens
+
+ def _emit(self, ttype: TokenType, value: str, raw: str = "") -> None:
+ self.tokens.append(
+ Token(ttype, value, self.line, self.column - len(raw), raw or value)
+ )
+
+ def _tokenize_ppmck(self, ch: str, start_line: int, start_col: int) -> None: # noqa: ARG002
+ if ch == "\n":
+ self._advance()
+ return
+ if ch == ";":
+ raw = self._read_until_newline()
+ self._emit(TokenType.COMMENT, raw, raw)
+ return
+ if ch == "#":
+ raw = "#" + self._read_until_newline()
+ self._emit(TokenType.HEADER, raw, raw)
+ return
+ if ch == "|":
+ self._advance()
+ self._emit(TokenType.BAR, "|", "|")
+ return
+ if ch == ">":
+ self._advance()
+ self._emit(TokenType.OCTAVE_UP, ">", ">")
+ return
+ if ch == "<":
+ self._advance()
+ self._emit(TokenType.OCTAVE_DOWN, "<", "<")
+ return
+ if ch == "&":
+ self._advance()
+ self._emit(TokenType.TIE, "&", "&")
+ return
+ if ch == "[":
+ self._advance()
+ self._emit(TokenType.REPEAT_START, "[", "[")
+ return
+ if ch == "]":
+ self._advance()
+ count = self._read_number()
+ self._emit(TokenType.REPEAT_END, count, "]" + count)
+ return
+ if ch == ".":
+ self._advance()
+ self._emit(TokenType.DOT, ".", ".")
+ return
+ if ch == "+":
+ self._advance()
+ self._emit(TokenType.SHARP, "+", "+")
+ return
+ if ch == "-":
+ self._advance()
+ self._emit(TokenType.FLAT, "-", "-")
+ return
+ if ch.isdigit():
+ num = self._read_number()
+ self._emit(TokenType.NUMBER, num, num)
+ return
+ if _track_header_char(ch):
+ raw = self._advance()
+ self._emit(TokenType.TRACK_HEADER, raw.upper(), raw)
+ return
+ if ch.isalpha():
+ cmd = self._advance()
+ if ch in "olvtq":
+ num = self._read_number()
+ raw = cmd + num
+ if ch == "o":
+ self._emit(TokenType.OCTAVE, num, raw)
+ elif ch == "l":
+ self._emit(TokenType.LENGTH, num, raw)
+ elif ch == "v":
+ self._emit(TokenType.VOLUME, num, raw)
+ elif ch == "t":
+ self._emit(TokenType.TEMPO, num, raw)
+ elif ch == "q":
+ self._emit(TokenType.DUTY, num, raw)
+ return
+ # Note commands
+ note = ch.lower()
+ if note in "cdefgabr":
+ if note == "r":
+ self._emit(TokenType.REST, note, note)
+ else:
+ self._emit(TokenType.NOTE, note, note)
+ return
+ # Unknown command
+ self._emit(TokenType.TEXT, cmd, cmd)
+ return
+ # Fallback invalid char
+ raw = self._advance()
+ self._emit(TokenType.TEXT, raw, raw)
+
+ def _tokenize_pyxel(self, ch: str, start_line: int, start_col: int) -> None: # noqa: ARG002
+ if ch == "\n":
+ self._advance()
+ return
+ if ch == "|":
+ self._advance()
+ self._emit(TokenType.BAR, "|", "|")
+ return
+ if ch == ">":
+ self._advance()
+ self._emit(TokenType.OCTAVE_UP, ">", ">")
+ return
+ if ch == "<":
+ self._advance()
+ self._emit(TokenType.OCTAVE_DOWN, "<", "<")
+ return
+ if ch == "&":
+ self._advance()
+ self._emit(TokenType.TIE, "&", "&")
+ return
+ if ch == "[":
+ self._advance()
+ self._emit(TokenType.REPEAT_START, "[", "[")
+ return
+ if ch == "]":
+ self._advance()
+ count = self._read_number()
+ self._emit(TokenType.REPEAT_END, count, "]" + count)
+ return
+ if ch == ".":
+ self._advance()
+ self._emit(TokenType.DOT, ".", ".")
+ return
+ if ch == "+":
+ self._advance()
+ self._emit(TokenType.SHARP, "+", "+")
+ return
+ if ch == "-":
+ self._advance()
+ self._emit(TokenType.FLAT, "-", "-")
+ return
+ if ch.isdigit():
+ num = self._read_number()
+ if self._peek() == ":":
+ self._advance()
+ self._emit(TokenType.TRACK_HEADER, num, num + ":")
+ else:
+ self._emit(TokenType.NUMBER, num, num)
+ return
+ if ch == "@":
+ self._advance()
+ if self.source[self.pos : self.pos + 3].upper() in ("ENV", "VIB", "GLI"):
+ ext = self.source[self.pos : self.pos + 3].upper()
+ self.pos += 3
+ self.column += 3
+ raw = "@" + ext
+ self._emit(TokenType.EXT_CMD, ext, raw)
+ return
+ num = self._read_number()
+ self._emit(TokenType.AT, num, "@" + num)
+ return
+ if ch.isalpha():
+ cmd = self._advance()
+ if cmd in "OLVTQKY":
+ num = self._read_number()
+ raw = cmd + num
+ if cmd == "O":
+ self._emit(TokenType.OCTAVE, num, raw)
+ elif cmd == "L":
+ self._emit(TokenType.LENGTH, num, raw)
+ elif cmd == "V":
+ self._emit(TokenType.VOLUME, num, raw)
+ elif cmd == "T":
+ self._emit(TokenType.TEMPO, num, raw)
+ elif cmd == "Q":
+ self._emit(TokenType.GATE_TIME, num, raw)
+ elif cmd == "K":
+ self._emit(TokenType.TRANSPOSE, num, raw)
+ elif cmd == "Y":
+ self._emit(TokenType.DETUNE, num, raw)
+ return
+ note = cmd.upper()
+ if note in "CDEFGABR":
+ if note == "R":
+ self._emit(TokenType.REST, note, note)
+ else:
+ self._emit(TokenType.NOTE, note, note)
+ return
+ self._emit(TokenType.TEXT, cmd, cmd)
+ return
+ # Fallback
+ raw = self._advance()
+ self._emit(TokenType.TEXT, raw, raw)
+
+
+def tokenize(source: str, mode: str = "ppmck") -> list[Token]:
+ return Lexer(source, mode).tokenize()
+
+
+def iter_token_text(tokens: Iterable[Token]) -> str:
+ return " ".join(f"{t.type.name}:{t.value}" for t in tokens)
generated by cgit v1.2.3 (git 2.39.1) at 2026-10-19 15:13:26 +0000