Pretty print programs partially

src/main.rs

@@ -1,7 +1,6 @@
 use std::fs;
 use std::path::PathBuf;
 
-use ::pretty::{Pretty, RcAllocator};
 use chumsky::Parser as _;
 use clap::Parser;
 
@@ -48,17 +47,14 @@ fn main() -> anyhow::Result<()> {
             let stream = span::stream_from_str(&content);
             match parser::parser().parse(stream) {
                 Ok(program) => {
-                    println!("Successful parse");
-                    let doc = program.pretty(&RcAllocator);
                     let mut out = vec![];
-                    doc.render(100, &mut out)?;
-                    let str = String::from_utf8(out)?;
-                    println!("{str}");
+                    program.to_doc().render(100, &mut out)?;
+                    println!("{}", String::from_utf8(out)?);
                 }
                 Err(errs) => {
-                    println!("Parsing failed");
+                    eprintln!("Parsing failed");
                     for err in errs {
-                        println!("{err:?}");
+                        eprintln!("{err:?}");
                     }
                 }
             }

src/pretty.rs

@@ -1,9 +1 @@
-use pretty::{DocAllocator, DocBuilder, Pretty};
-
-use crate::ast::Program;
-
-impl<'a, A: DocAllocator<'a>> Pretty<'a, A> for Program {
-    fn pretty(self, allocator: &'a A) -> DocBuilder<'a, A, ()> {
-        allocator.text("Hello world")
-    }
-}
+mod program;

src/pretty/program.rs

@@ -0,0 +1,23 @@
+use pretty::RcDoc;
+
+use crate::ast::Program;
+
+impl Program {
+    pub fn to_doc(&self) -> RcDoc {
+        match self {
+            Program::Expr {
+                s0,
+                expr,
+                s1,
+                span: _,
+            } => RcDoc::nil(),
+            Program::Module {
+                s0,
+                s1,
+                elems,
+                s2,
+                span: _,
+            } => RcDoc::text("module"),
+        }
+    }
+}