[] and () are considered as punctuation in lyrics and can start them.
In contrast, "TeX accents" \' \" \` \^ are quite ridiculous to
"support" in lyrics since LilyPond has not been using TeX for a long
time now, so those sequences are no longer considered special in
lyrics.
N [0-9]
AN {AA}|{N}
ANY_CHAR (.|\n)
N [0-9]
AN {AA}|{N}
ANY_CHAR (.|\n)
-PUNCT [?!:'`]
-ACCENT \\[`'"^]
SPECIAL_CHAR [&@]
NATIONAL [\001-\006\021-\027\031\036]
SPECIAL_CHAR [&@]
NATIONAL [\001-\006\021-\027\031\036]
-TEX {AA}|-|{PUNCT}|{ACCENT}|{NATIONAL}|{SPECIAL_CHAR}
+TEX {AA}|-|{PUNCT}|{NATIONAL}|{SPECIAL_CHAR}
DASHED_WORD {A}({AN}|-)*
DASHED_KEY_WORD \\{DASHED_WORD}
DASHED_WORD {A}({AN}|-)*
DASHED_KEY_WORD \\{DASHED_WORD}