feature calt {

# — Rule 2: t or T between L/l and J-family → T.alt3 —
sub L t’ J by T.alt3;
sub L t’ j by T.alt3;
sub L t’ J.alt2 by T.alt3;

sub l t’ J by T.alt3;
sub l t’ j by T.alt3;
sub l t’ J.alt2 by T.alt3;

sub L T’ J by T.alt3;
sub L T’ j by T.alt3;
sub L T’ J.alt2 by T.alt3;

sub l T’ J by T.alt3;
sub l T’ j by T.alt3;
sub l T’ J.alt2 by T.alt3;

# — Rule 1: t or T followed by J-family → T.alt2 —
sub t’ J by T.alt2;
sub t’ j by T.alt2;
sub t’ J.alt2 by T.alt2;

sub T’ J by T.alt2;
sub T’ j by T.alt2;
sub T’ J.alt2 by T.alt2;

# — Rule 3: J-family preceded by T-family → J.alt2 —
# Covers plain t/T
sub t J’ by J.alt2;
sub t j’ by J.alt2;
sub t J.alt2′ by J.alt2;

sub T J’ by J.alt2;
sub T j’ by J.alt2;
sub T J.alt2′ by J.alt2;

# Covers substituted Ts (chaining)
sub T.alt2 J’ by J.alt2;
sub T.alt2 j’ by J.alt2;
sub T.alt2 J.alt2′ by J.alt2;

sub T.alt3 J’ by J.alt2;
sub T.alt3 j’ by J.alt2;
sub T.alt3 J.alt2′ by J.alt2;

@LettersUpperNoL = [A B C D E F G H I J K M N O P Q R S T U V W X Y Z];
@LettersLowerNoL = [a b c d e f g h i j k m n o p q r s t u v w x y z];
@LettersNoL = [@LettersUpperNoL @LettersLowerNoL];

# t/T → T.alt3 when before . or , AND preceded by L/l or . or ,
lookup T_before_punct_alt3 {
sub [L l period comma] t’ [period comma] by T.alt3;
sub [L l period comma] T’ [period comma] by T.alt3;
} T_before_punct_alt3;

# t/T → T.alt2 when before . or , (general case)
lookup T_before_punct_alt2 {
sub t’ [period comma] by T.alt2;
sub T’ [period comma] by T.alt2;
} T_before_punct_alt2;

# t/T → T.alt2 when followed by space AND preceded by a non-L letter
lookup T_before_space_after_nonL {
sub @LettersNoL t’ space by T.alt2;
sub @LettersNoL T’ space by T.alt2;
} T_before_space_after_nonL;

} calt;
feature ss01 {
sub T by T.alt2;
sub t by T.alt2;
} ss01;

feature ss02 {
sub T by T.alt3;
sub t by T.alt3;
} ss02;

feature ss03 {
sub J by J.alt2;
sub j by J.alt2;
} ss03;