LilyPond scheme predicates

These predicates are only available within LilyPond and defined in Scheme.

Type predicateDescription
alist?association list (list of pairs)
boolean-or-symbol?boolean or symbol
cheap-list?list (use this instead of list? for faster processing)
exact-rational?an exact rational number
fraction?fraction, as pair
grob-list?list of grobs
index?non-negative, exact integer
index-or-markup?index or markup
key?index or symbol
key-list?list of indices or symbols
key-list-or-music?key list or music
key-list-or-symbol?key list or symbol
ly:skyline-pair?pair of skylines
markup-command-list?markup command list
markup-list?markup list
moment-pair?pair of moment objects
musical-length?non-negative moment with no grace part
non-negative-number?non-negative number
number-list?number list
number-or-grob?number or grob
number-or-pair?number or pair
number-or-string?number or string
number-pair?pair of numbers
number-pair-list?list of number pairs
positive-fraction?positive, finite fraction, as pair
positive-musical-length?positive moment with no grace part
positive-number?positive number
rational-or-procedure?an exact rational or procedure
rhythmic-location?rhythmic location
scale?non-negative rational, fraction, or moment
scheme?any type
string-or-music?string or music
string-or-pair?string or pair
string-or-symbol?string or symbol
symbol-key-alist?alist, with symbols as keys
symbol-list?symbol list
symbol-list-or-music?symbol list or music
symbol-list-or-symbol?symbol list or symbol

LilyPond — Notation Reference v2.25.8 (development-branch).