Partial work toward a PEG parser library

src/labels/labels.rs

@@ -0,0 +1,14 @@
+use super::super::preprocess::peg::Parser;
+use anyhow::Result;
+
+fn parse_program(p: &mut Parser) -> Result<()> {
+    p.star(|p| parse_line(p))?;
+    p.eof()?;
+    Ok(())
+}
+
+fn parse_line(p: &mut Parser) -> Result<()> {
+    p.star(|p| p.char(|c| c != '\n'))?;
+    p.literal("\n")?;
+    Ok(())
+}