Add "pretty" subcommand

Cargo.lock

@@ -17,6 +17,12 @@ version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "216261ddc8289130e551ddcd5ce8a064710c0d064a4d2895c67151c92b5443f6"
 
+[[package]]
+name = "arrayvec"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23b62fc65de8e4e7f52534fb52b0f3ed04746ae267519eef2a83941e8085068b"
+
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -146,6 +152,15 @@ version = "0.2.137"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fc7fcc620a3bff7cdd7a365be3376c97191aeaccc2a603e600951e452615bf89"
 
+[[package]]
+name = "log"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.16.0"
@@ -158,6 +173,18 @@ version = "6.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b5bf27447411e9ee3ff51186bf7a08e16c341efdde93f4d823e8844429bed7e"
 
+[[package]]
+name = "pretty"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "83f3aa1e3ca87d3b124db7461265ac176b40c277f37e503eaa29c9c75c037846"
+dependencies = [
+ "arrayvec",
+ "log",
+ "typed-arena",
+ "unicode-segmentation",
+]
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -230,6 +257,7 @@ dependencies = [
  "anyhow",
  "chumsky",
  "clap",
+ "pretty",
 ]
 
 [[package]]
@@ -250,12 +278,24 @@ dependencies = [
  "crunchy",
 ]
 
+[[package]]
+name = "typed-arena"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0685c84d5d54d1c26f7d3eb96cd41550adb97baed141a761cf335d3d33bcd0ae"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ceab39d59e4c9499d4e5a8ee0e2735b891bb7308ac83dfb4e80cad195c9f6f3"
 
+[[package]]
+name = "unicode-segmentation"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fdbf052a0783de01e944a6ce7a8cb939e295b1e7be835a1112c3b9a7f047a5a"
+
 [[package]]
 name = "version_check"
 version = "0.9.4"

Cargo.toml

@@ -7,3 +7,4 @@ edition = "2021"
 anyhow = "1.0.66"
 chumsky = "0.8.0"
 clap = { version = "4.0.26", features = ["derive", "deprecated"] }
+pretty = "0.11.3"

src/main.rs

@@ -1,12 +1,14 @@
 use std::fs;
 use std::path::PathBuf;
 
+use ::pretty::{Pretty, RcAllocator};
 use chumsky::Parser as _;
 use clap::Parser;
 
 mod ast;
 mod builtin;
 mod parser;
+mod pretty;
 mod span;
 mod table;
 mod value;
@@ -14,6 +16,7 @@ mod value;
 #[derive(Parser)]
 enum Command {
     Parse { file: PathBuf },
+    Pretty { file: PathBuf },
 }
 
 #[derive(Parser)]
@@ -31,7 +34,27 @@ fn main() -> anyhow::Result<()> {
             let content = fs::read_to_string(&file)?;
             let stream = span::stream_from_str(&content);
             match parser::parser().parse(stream) {
-                Ok(lit) => println!("Successful parse: {lit:#?}"),
+                Ok(program) => println!("Successful parse: {program:#?}"),
+                Err(errs) => {
+                    println!("Parsing failed");
+                    for err in errs {
+                        println!("{err:?}");
+                    }
+                }
+            }
+        }
+        Command::Pretty { file } => {
+            let content = fs::read_to_string(&file)?;
+            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}");
+                }
                 Err(errs) => {
                     println!("Parsing failed");
                     for err in errs {

src/pretty.rs

@@ -0,0 +1,9 @@
+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")
+    }
+}