lookup subs {
    sub @SUBS1 by @SUBS2;
} subs;

feature subs {
    lookup subs;
} subs; 

feature dnom {
    lookup subs;
} dnom;

lookup ordn {
    sub @SUBS1 by @ORDN;
} ordn;

feature ordn {
    lookup ordn;
} ordn;

feature numr {
    lookup ordn;
} numr;

lookup sinf {
    sub @SUBS1 by @SINF;
} sinf;

feature sinf {
    lookup sinf;
} sinf;

lookup sups {
    sub @SUBS1 by @SUPS;
} sups;

feature sups {
    lookup sups;
} sups;

lookup frac_slash {
 sub slash by fraction;
} frac_slash;

lookup frac {
 sub [ slash fraction @DIGITS @DIGITS_SUBS ] @DIGITS' by @DIGITS_SUBS;
 sub @DIGITS' [ slash fraction @DIGITS @DIGITS_ORDN ] by @DIGITS_ORDN;
} frac;

feature frac {
 lookup frac_slash;
 lookup frac;
} frac;

feature lnum {
    sub @ONUM by @LNUM;
    sub @ONUM_TNUM by @LNUM_TNUM;
} lnum;

feature onum {
    sub @LNUM by @ONUM;
    sub @LNUM_TNUM by @ONUM_TNUM;
} onum;

feature tnum {
    sub @ONUM by @ONUM_TNUM;
    sub @LNUM by @LNUM_TNUM;
} tnum;

feature pnum {
    sub @ONUM_TNUM by @ONUM;
    sub @LNUM_TNUM by @LNUM;
} pnum;