bng syntax rules & poc

src/bng/score.rs

@@ -0,0 +1,42 @@
+use fasteval::Instruction;
+
+mod lex;
+
+pub(super) enum Atom {
+    Note(u8),
+    Rest,
+    StartHere,
+    Modifier(Modifier),
+    QuickModifier(QuickModifier),
+    Wrapper(WrapperKind, Vec<Atom>),
+    EmptyWrapper(WrapperKind),
+}
+
+pub(super) enum Modifier {
+    Volume(u8),
+    Octave(u8),
+    Length(u8),
+    Tempo(u16),
+}
+
+pub(super) enum QuickModifier {
+    Volume(bool),
+    Octave(bool),
+    Length(bool),
+    Pizz(bool),
+}
+
+pub(super) enum WrapperKind {
+    Loop(u8),
+    Tuple,
+    Slope(SlopeModifier, Instruction),
+    Comment,
+}
+
+pub(super) enum SlopeModifier {
+    Note,
+    Volume,
+    Octave,
+    Length,
+    Tempo,
+}

src/bng/score/lex.rs

@@ -0,0 +1,50 @@
+use super::{Atom, Modifier, WrapperKind};
+const MORE: bool = true;
+const LESS: bool = false;
+const ON: bool = true;
+const OFF: bool = false;
+
+struct WrappingTokens;
+impl WrappingTokens {
+    const PARENTHESES: (char, char) = ('(', ')');
+    const SQUARE_BRACKETS: (char, char) = ('[', ']');
+    const BRACKETS: (char, char) = ('{', '}');
+    const SEMICOLON_COMMA: (char, char) = (';', ',');
+}
+
+trait Token<T> {
+    fn token(self) -> T;
+}
+
+impl Token<(char, char)> for WrapperKind {
+    fn token(self) -> (char, char) {
+        match self {
+            Self::Loop(_) => WrappingTokens::PARENTHESES,
+            Self::Tuple => WrappingTokens::SQUARE_BRACKETS,
+            Self::Slope(_, _) => WrappingTokens::BRACKETS,
+            WrapperKind::Comment => WrappingTokens::SEMICOLON_COMMA,
+        }
+    }
+}
+
+impl Token<char> for Modifier {
+    fn token(self) -> char {
+        match self {
+            Self::Volume(_) => 'v',
+            Self::Octave(_) => 'o',
+            Self::Length(_) => 'l',
+            Self::Tempo(_) => 't',
+        }
+    }
+}
+
+impl Token<char> for Atom {
+    fn token(self) -> char {
+        match self {
+            Atom::Rest => '.',
+            Atom::StartHere => ':',
+            Atom::Modifier(_) => '!',
+            _ => unimplemented!("not a singleton"),
+        }
+    }
+}

src/main.rs

@@ -1,9 +1,11 @@
+#![feature(unsize)]
 use clap::Parser;
 
 mod bng;
 mod cli;
 
 fn main() {
+    // println!("{}", option_env!("TEST").unwrap_or("ok"));
     let args = cli::BngCli::parse();
     #[cfg(debug_assertions)]
     println!("{:?}", args);