// © Copyright 2022, Scott Gasch
//
// antlr4 -Dlanguage=Python3 ./chords.g4
//
// Hi, self.  In ANTLR grammars, there are two separate types of symbols: those
// for the lexer and those for the parser.  The former begin with a CAPITAL
// whereas the latter begin with lowercase.  The order of the lexer symbols
// is the order that the lexer will recognize them in.  There's a good tutorial
// on this shit at:
//
//    https://tomassetti.me/antlr-mega-tutorial/
//
// There are also a zillion premade grammars at:
//
//    https://github.com/antlr/grammars-v4

grammar chords;

parse
    : rootNote majMinSusPowerExpr* addNotesExpr* overBassNoteExpr*
    | rootNote majMinSusPowerExpr* addNotesExpr extensionExpr* overBassNoteExpr
    ;

rootNote
    : NOTE
    ;

overBassNoteExpr
    : SLASH NOTE
    ;

majMinSusPowerExpr
    : majExpr
    | minExpr
    | susExpr
    | diminishedExpr
    | augmentedExpr
    | powerChordExpr
    ;

majExpr: MAJOR;

minExpr: MINOR;

susExpr: SUS ('2'|'4');

diminishedExpr: DIMINISHED;

augmentedExpr: AUGMENTED;

powerChordExpr: '5';

addNotesExpr
    : ADD* SIX
    | ADD* SEVEN
    | MAJ_SEVEN
    | MIN_SEVEN
    | ADD* NINE
    | ADD* ELEVEN
    ;

extensionExpr
    : INTERVAL
    ;

SPACE: [ \t\r\n] -> skip;

NOTE: (AS|BS|CS|DS|ES|FS|GS) ;

AS
    : ('A'|'a')
    | ('Ab'|'ab')
    | ('A#'|'a#')
    ;

BS
    : ('B'|'b')
    | ('Bb'|'bb')
    ;

CS
    : ('C'|'c')
    | ('C#'|'c#')
    ;

DS
    : ('D'|'d')
    | ('Db'|'db')
    | ('D#'|'d#')
    ;

ES
    : ('E'|'e')
    | ('Eb'|'eb')
    ;

FS
    : ('F'|'f')
    | ('F#'|'f#')
    ;

GS
    : ('G'|'g')
    | ('Gb'|'gb')
    | ('G#'|'g#')
    ;

MAJOR: ('M'|'Maj'|'maj'|'Major'|'major');

MINOR: ('m'|'min'|'minor');

SUS: ('sus'|'suspended');

DIMINISHED: ('dim'|'diminished'|'-');

AUGMENTED: ('aug'|'augmented'|'+');

SLASH: ('/'|'\\');

ADD: ('add'|'Add'|'dom');

SIX: '6';

SEVEN: '7';

NINE: '9';

ELEVEN: '11';

MAJ_SEVEN: MAJOR '7';

MIN_SEVEN: MINOR '7';

INTERVAL: (MAJOR|MINOR)* ('b'|'#')* DIGITS ;

DIGITS: [1-9]+ ;