feat: add cli to output for graphviz

simpcli/src/main.rs

@@ -28,6 +28,7 @@ fn usage(process_name: &str) {
     eprintln!("Usage:");
     eprintln!("  {} assemble <filename>", process_name);
     eprintln!("  {} disassemble <base64>", process_name);
+    eprintln!("  {} graph <base64>", process_name);
     eprintln!("  {} relabel <base64>", process_name);
     eprintln!();
     eprintln!("For commands which take an optional expression, the default value is \"main\".");
@@ -43,6 +44,7 @@ fn invalid_usage(process_name: &str) -> Result<(), String> {
 enum Command {
     Assemble,
     Disassemble,
+    Graph,
     Relabel,
     Help,
 }
@@ -53,6 +55,7 @@ impl FromStr for Command {
         match s {
             "assemble" => Ok(Command::Assemble),
             "disassemble" => Ok(Command::Disassemble),
+            "graphviz" | "dot" | "graph" => Ok(Command::Graph),
             "relabel" => Ok(Command::Relabel),
             "help" => Ok(Command::Help),
             x => Err(format!("unknown command {}", x)),
@@ -65,6 +68,7 @@ impl Command {
         match *self {
             Command::Assemble => false,
             Command::Disassemble => false,
+            Command::Graph => false,
             Command::Relabel => false,
             Command::Help => false,
         }
@@ -155,6 +159,14 @@ fn main() -> Result<(), String> {
             let prog = Forest::<DefaultJet>::from_program(commit);
             println!("{}", prog.string_serialize());
         }
+        Command::Graph => {
+            let v = simplicity::base64::Engine::decode(&STANDARD, first_arg.as_bytes())
+                .map_err(|e| format!("failed to parse base64: {}", e))?;
+            let iter = BitIter::from(v.into_iter());
+            let commit = CommitNode::<DefaultJet>::decode(iter)
+                .map_err(|e| format!("failed to decode program: {}", e))?;
+            println!("{}", commit.display_as_dot());
+        }
         Command::Relabel => {
             let prog = parse_file(&first_arg)?;
             println!("{}", prog.string_serialize());

src/node/display.rs

@@ -197,6 +197,39 @@ where
     }
 }
 
+pub struct DisplayAsDot<'a, M: Marker>(&'a Node<M>);
+
+impl<'a, M: Marker> From<&'a Node<M>> for DisplayAsDot<'a, M> {
+    fn from(node: &'a Node<M>) -> Self {
+        Self(node)
+    }
+}
+
+impl<'a, M: Marker> fmt::Display for DisplayAsDot<'a, M>
+where
+    &'a Node<M>: DagLike,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        writeln!(f, "digraph G {{")?;
+        writeln!(f, "ordering=\"out\";")?;
+
+        for data in self.0.post_order_iter::<NoSharing>() {
+            let node_name = data.node.inner().to_string();
+            writeln!(f, "  node{}[label=\"{}\"];", data.index, node_name)?;
+            if let Some(left) = data.left_index {
+                writeln!(f, "  node{}->node{};", data.index, left)?;
+            }
+            if let Some(right) = data.right_index {
+                writeln!(f, "  node{}->node{};", data.index, right)?;
+            }
+        }
+
+        writeln!(f, "}}")?;
+
+        Ok(())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::human_encoding::Forest;
@@ -241,4 +274,54 @@ mod tests {
             program.display_expr().to_string()
         )
     }
+
+    #[test]
+    fn display_as_dot() {
+        let s = "
+            oih := take drop iden
+            input := pair (pair unit unit) unit
+            output := unit
+            main := comp input (comp (pair oih (take unit)) output)";
+        let program = parse_program(s);
+        let str = program
+            .display_as_dot()
+            .to_string()
+            .replace(" ", "")
+            .replace("\n", "");
+        let expected = "
+        digraph G {
+ordering=\"out\";
+  node0[label=\"unit\"];
+  node1[label=\"unit\"];
+  node2[label=\"pair\"];
+  node2->node0;
+  node2->node1;
+  node3[label=\"unit\"];
+  node4[label=\"pair\"];
+  node4->node2;
+  node4->node3;
+  node5[label=\"iden\"];
+  node6[label=\"drop\"];
+  node6->node5;
+  node7[label=\"take\"];
+  node7->node6;
+  node8[label=\"unit\"];
+  node9[label=\"take\"];
+  node9->node8;
+  node10[label=\"pair\"];
+  node10->node7;
+  node10->node9;
+  node11[label=\"unit\"];
+  node12[label=\"comp\"];
+  node12->node10;
+  node12->node11;
+  node13[label=\"comp\"];
+  node13->node4;
+  node13->node12;
+}"
+        .replace(" ", "")
+        .replace("\n", "");
+
+        assert_eq!(str, expected);
+    }
 }

src/node/mod.rs

@@ -66,6 +66,7 @@
 use crate::dag::{DagLike, MaxSharing, SharingTracker};
 use crate::encode;
 use crate::jet::Jet;
+use crate::node::display::DisplayAsDot;
 use crate::{types, BitWriter, Cmr, FailEntropy, HasCmr, Value};
 
 use std::sync::Arc;
@@ -723,6 +724,10 @@ impl<N: Marker> Node<N> {
         DisplayExpr::from(self)
     }
 
+    pub fn display_as_dot(&self) -> DisplayAsDot<'_, N> {
+        DisplayAsDot::from(self)
+    }
+
     /// Encode a Simplicity expression to bits without any witness data.
     pub fn encode_without_witness<W: io::Write>(&self, prog: W) -> io::Result<usize> {
         let mut w = BitWriter::new(prog);