replace total note length variable from l to L, swap fasteval log_2 with log(2,...), fix silence rendering, first compiler test

doc/cli-design.txt

@@ -16,7 +16,7 @@ modes:
         -i EXPR, --instrument EXPR
             signal expression (instrument) to generate music samples (you can use the floating-point number t for the current time in seconds, n for the indice of the currently playing note in the list of available notes starting with 0 and N for the number of available notes)  [default: "sin(2*PI*(442+442*((n+1)/N))*t)"]
         -l EXPR, --length EXPR
-            expression to generate note length in seconds  [default: "2^(2-log_2(l))*(60/T)"]
+            expression to generate note length in seconds  [default: "2^(2-log(2, l))*(60/T)"]
         -v VARIABLE=VALUE, --variable VARIABLE=VALUE
             add a variable named VARIABLE (an single letter) for the sheet music and all expressions and set its initial value to VALUE (you can override n, t, l and T which is the only way to set the initial tempo)
         -m NAME:EXPANSION, --macro NAME:EXPANSION
@@ -34,7 +34,7 @@ modes:
         -i EXPR, --instrument EXPR
             signal expression (instrument) to generate music samples (you can use the floating-point number t for the current time in seconds, n for the indice of the currently playing note in the list of available notes starting with 0 and N for the number of available notes)  [default: "sin(2*PI*(442+442*((n+1)/N))*t)"]
         -l EXPR, --length EXPR
-            expression to generate note length in seconds  [default: "2^(2-log_2(l))*(60/T)"]
+            expression to generate note length in seconds  [default: "2^(2-log(2, l))*(60/T)"]
         -v VARIABLE=VALUE, --variable VARIABLE=VALUE
             add a variable named VARIABLE (an single letter) for the sheet music and all expressions and set its initial value to VALUE (you can override n, t, l and T which is the only way to set the initial tempo)
         -m NAME:EXPANSION, --macro NAME:EXPANSION

src/cli/main.rs

@@ -29,7 +29,7 @@ use strum::{EnumDiscriminants, EnumString, IntoDiscriminant, IntoStaticStr};
 use thiserror::Error;
 
 const DEFAULT_INSTRUMENT: &str = "sin(2*PI*(442+442*((n+1)/N))*t)";
-const DEFAULT_LENGTH: &str = "2^(2-log_2(l))*(60/T)";
+const DEFAULT_LENGTH: &str = "2^(2-log(2, l))*(60/T)";
 
 fn main() {
     let cli = Cli::parse();

src/compiler.rs

@@ -66,7 +66,8 @@ impl_type!(Silence);
 
 impl Token for Silence {
     fn apply(&self, mut context: Context) -> Result<Context, CompilerError> {
-        context.render(None)?;
+        let mut next = context.render(None)?;
+        context.result.append(&mut next);
         Ok(context)
     }
 }
@@ -266,14 +267,17 @@ pub struct Context {
 }
 
 #[derive(Debug, Error)]
+#[cfg_attr(test, derive(PartialEq))]
 #[error("variable not found: {0}")]
 pub struct VariableNotFoundError(char);
 
 #[derive(Debug, Error)]
+#[cfg_attr(test, derive(PartialEq))]
 #[error("expression not found: {0}")]
 pub struct SlopeNotFoundError(char);
 
 #[derive(Debug, Error)]
+#[cfg_attr(test, derive(PartialEq))]
 pub enum CompilerError {
     #[error("expression evaluation: {0:?}")]
     FastEval(#[from] fasteval::Error),
@@ -284,19 +288,21 @@ pub enum CompilerError {
 }
 
 impl Context {
-    pub fn current_length(&mut self) -> Result<f64, CompilerError> {
+    pub fn current_length(&self) -> Result<f64, CompilerError> {
-        *self = self
+        self.get_slopes_for('L')
-            .get_slopes_for('L')
             .map_err(CompilerError::from)?
             .iter()
             .try_fold(
                 self.clone(),
                 |mut acc, slope| -> Result<Context, CompilerError> {
+                    // just in case next slopes use L too
                     *acc.get_mut('L')? = self.eval(slope).map_err(Into::<CompilerError>::into)?;
                     Ok(acc)
                 },
-            )?;
+            )?
-        Ok(*self.get('L')?)
+            .get('L')
+            .map_err(Into::into)
+            .cloned()
     }
 
     pub fn get(&self, name: char) -> Result<&f64, VariableNotFoundError> {
@@ -323,13 +329,11 @@ impl Context {
     }
 
     fn tick(&mut self) -> Result<(), CompilerError> {
-        *self.get_mut('t')? += 1f64 / SAMPLE_RATE as f64;
+        *self.get_mut('t')? += 1f64 / (SAMPLE_RATE as f64);
-        {
+        *self = self.slopes.iter().try_fold(
-            let changes = self
+            self.clone(),
-                .slopes
+            |mut acc,
-                .iter()
+             (
-                .map(
-                    |(
                 v,
                 Expression {
                     from: _,
@@ -337,25 +341,18 @@ impl Context {
                     slab,
                 },
             )|
-                     -> Result<(char, f64), fasteval::Error> {
+             -> Result<Self, CompilerError> {
-                        Ok((
+                *acc.get_mut(*v)? = instruction.eval(
-                            *v,
-                            instruction.eval(
                     slab,
-                                &mut self
+                    &mut acc
                         .variables
                         .iter()
                         .map(|(c, f)| (c.to_string(), *f))
                         .collect::<BTreeMap<String, f64>>(),
-                            )?,
+                )?;
-                        ))
+                Ok(acc)
             },
-                )
+        )?;
-                .collect::<Result<Vec<(char, f64)>, fasteval::Error>>()?;
-            for (variable, new_value) in changes {
-                *self.get_mut(variable)? = new_value;
-            }
-        }
         Ok(())
     }
 
@@ -398,10 +395,14 @@ impl Context {
             }
             Ok(result)
         } else {
-            while (self.current_length()? * SAMPLE_RATE as f64) > *self.get('t')? - curr_t {
+            while (self.current_length()?) > *self.get('t')? - curr_t {
                 self.tick()?;
             }
-            Ok(vec![0.0; (*self.get('t')? - curr_t) as usize])
+            Ok(vec![
+                0.0;
+                ((*self.get('t')? - curr_t) * SAMPLE_RATE as f64)
+                    as usize
+            ])
         }
     }
 
@@ -411,29 +412,34 @@ impl Context {
 }
 
 #[derive(From)]
+#[cfg_attr(test, derive(Debug, PartialEq))]
 struct Compiler(Context);
 
 impl Compiler {
-    fn step(self, token: impl Token) -> Result<Self, CompilerError> {
+    pub fn step(self, token: impl Token) -> Result<Self, CompilerError> {
         token.apply(self.0).map(Into::into)
     }
-    fn compile_all(
+    fn apply_all(
         self,
         tokens: impl IntoIterator<Item = impl Token>,
-    ) -> Result<Vec<f64>, CompilerError> {
+    ) -> Result<Self, CompilerError> {
         tokens
             .into_iter()
             .try_fold(self, |acc, token| acc.step(token))
-            .map(|c| c.0)
+    }
-            .map(Context::finalize)
+    pub fn compile_all(
+        self,
+        tokens: impl IntoIterator<Item = impl Token>,
+    ) -> Result<Vec<f64>, CompilerError> {
+        self.apply_all(tokens).map(|c| c.0).map(Context::finalize)
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use crate::compiler::Expression;
+    use crate::compiler::{Compiler, Expression, SAMPLE_RATE, Silence};
 
-    use super::Context;
+    use super::{CompilerError, Context};
 
     #[test]
     fn expression_is_clone() {
@@ -453,7 +459,20 @@ mod tests {
                 ('T', 60.0),
             ],
             "sin(2*PI*(442+442*((n+1)/N))*t)".parse().unwrap(),
-            [('L', "2^(2-log_2(l))*(60/T)")].map(|(c, e)| (c, e.parse().unwrap())),
+            [('L', "2^(2-log(2, l))*(60/T)")].map(|(c, e)| (c, e.parse().unwrap())),
         )
     }
+
+    #[test]
+    fn silence() -> Result<(), CompilerError> {
+        assert_eq!(
+            SAMPLE_RATE as usize,
+            Compiler::from(context_generator())
+                .apply_all(vec![Silence])?
+                .0
+                .result
+                .len()
+        );
+        Ok(())
+    }
 }