bng syntax rules & poc

Cargo.toml

@@ -4,11 +4,15 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+amplify = "4.7.0"
 anyhow = "1.0"
 cfg-if = "1.0.0"
 clap = { version = "4.5", features = ["derive"] }
 derived-deref = "2.1.0"
 fasteval = "0.2.4"
+nom = "7.1.3"
+serde = "1.0.209"
+serde_yml = "0.0.12"
 splines = "4.3.1"
 tinyaudio = { version = "0.1", optional = true }
 

poc/poc.yml

@@ -0,0 +1,44 @@
+# fixed
+instruments:
+  # instrument name
+  sine:
+    # fixed
+    expr: sin(2*PI*f*t) # instrument formula (f is the frequency in Hertz, t is the time in seconds)
+  square:
+    expr: v*abs(sin(2*PI*f*t))
+    # fixed
+    vars:
+      # name of the variable
+      v: 1 # initial value of the variable
+channels:
+  melody:
+    instr: sine
+    score:
+      aabc.
+      'rt°y
+      +d+d+d---
+      /ff/f\\
+      ab>c<ba
+      ;this is a comment (or lyrics whatever),
+      s:df
+      (3deff)
+      (deff)
+      [ffe]
+      {1-cos((PI*x)/2),acced}
+      abbc!o5cc!v15feed!l4fedd!t60hdd
+      # rest: .
+      # pizz.: '°
+      # volume: +-
+      # length: /\
+      # octave: ><
+      # comment?: ;,
+      # start here: ':'
+      # glissando: {EXPR, score}
+      # loop: ()
+      # loop with count: (COUNT, score)
+      # tuple: []
+      # modifier: !
+      #   volume modifier prefix: v
+      #   octave modifier prefix: o
+      #   length modifier prefix: l
+      #   tempo modifier prefix: t

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/cli.rs

@@ -1,5 +1,6 @@
-use std::path::PathBuf;
+use std::{fmt::Display, fs::read_to_string, io, str::FromStr};
 
+use amplify::{From, Wrapper};
 use clap::Parser;
 
 /// Cli entry point
@@ -8,9 +9,9 @@ use clap::Parser;
 pub enum BngCli {
     /// Play the song through default sink
     Play(PlayOpts),
-    /// Export the song to a sound file
+    /// Export the song to a sound FileContents
     Export(ExportOpts),
-    /// List supported sound file extensions and instrument / song available expressions
+    /// List supported sound FileContents extensions and instrument / song available expressions
     #[command(subcommand)]
     List(ListOpts),
 }
@@ -19,24 +20,27 @@ pub enum BngCli {
 #[derive(Clone, Parser)]
 #[cfg_attr(debug_assertions, derive(Debug))]
 pub struct PlayOpts {
-    input: PathBuf,
+    #[arg(value_parser = FileContents::from_str)]
+    input: FileContents,
 }
 
 /// [`BngCli`] "export" command options
 #[derive(Clone, Parser)]
 #[cfg_attr(debug_assertions, derive(Debug))]
 pub struct ExportOpts {
-    /// Input file (written song file)
-    input: PathBuf,
-    /// Output file (sound file)
-    output: PathBuf,
+    /// Input FileContents (written song FileContents)
+    #[arg(value_parser = FileContents::from_str)]
+    input: FileContents,
+    /// Output FileContents (sound FileContents)
+    #[arg(value_parser = AudioFileName::from_str)]
+    output: AudioFileName,
 }
 
 /// [`BngCli`] "list" command sub-commands
 #[derive(Clone, Parser)]
 #[cfg_attr(debug_assertions, derive(Debug))]
 pub enum ListOpts {
-    /// List supported sound file extensions to export songs
+    /// List supported sound FileContents extensions to export songs
     #[command(subcommand)]
     Extensions,
     /// List available math expressions for instrument definition
@@ -46,3 +50,41 @@ pub enum ListOpts {
     #[command(subcommand)]
     Glyphs,
 }
+
+#[derive(Clone, Wrapper, From)]
+#[wrapper(Deref)]
+#[cfg_attr(debug_assertions, derive(Debug))]
+pub struct FileContents(String);
+
+impl FromStr for FileContents {
+    type Err = io::Error;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        read_to_string(s).map(Into::into)
+    }
+}
+
+#[derive(Clone, Wrapper, From)]
+#[wrapper(Deref)]
+#[cfg_attr(debug_assertions, derive(Debug))]
+pub struct AudioFileName(String);
+
+#[derive(Debug)]
+pub struct UnsupportedFileExtensionError;
+
+impl std::error::Error for UnsupportedFileExtensionError {}
+
+impl Display for UnsupportedFileExtensionError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "The extension of the selected output sound file is not supported."
+        )
+    }
+}
+
+impl FromStr for AudioFileName {
+    type Err = UnsupportedFileExtensionError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(s.to_owned().into())
+    }
+}

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);