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//! Scheme source code minifier.

use stak_configuration::DEFAULT_HEAP_SIZE;
use stak_device::ReadWriteDevice;
use stak_macro::include_r7rs;
use stak_primitive::{SmallError, SmallPrimitiveSet};
use stak_vm::Vm;
use std::io::{empty, Read, Write};

/// Minifies given source codes.
pub fn minify(reader: impl Read, writer: impl Write) -> Result<(), SmallError> {
    const PROGRAM: &[u8] = include_r7rs!("minify.scm");

    let mut heap = vec![Default::default(); DEFAULT_HEAP_SIZE];
    let mut vm = Vm::new(
        &mut heap,
        SmallPrimitiveSet::new(ReadWriteDevice::new(reader, writer, empty())),
    )?;

    vm.initialize(PROGRAM.iter().copied())?;
    vm.run()?;

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use pretty_assertions::assert_eq;

    #[test]
    fn minify_expression() {
        let source = "(foo  bar)";
        let mut target = vec![];

        minify(source.as_bytes(), &mut target).unwrap();

        assert_eq!(target, b"(foo bar)\n");
    }

    #[test]
    fn minify_expressions() {
        let source = "(foo  bar)\n\n(  baz   blah  )";
        let mut target = vec![];

        minify(source.as_bytes(), &mut target).unwrap();

        assert_eq!(target, b"(foo bar)\n(baz blah)\n");
    }
}