Add pass description to nl_opt help

src/bin/nl_opt.rs

@@ -195,9 +195,27 @@ impl Pass for MarkCriticalPath {
     }
 }
 
-register_passes!(PrimitiveCell; PrintVerilog, DotGraph, Clean, DisconnectRegisters,
-                                DisconnectArcSet, MarkArcSet, RenameNets, ReportSccs,
-                                ReportDepth, MarkCriticalPath);
+register_passes!(PrimitiveCell; 
+    /// A dummy pass that emits the Verilog of the netlist.
+    PrintVerilog, 
+    /// Print the dot graph of the netlist
+    DotGraph,
+    /// Clean the netlist of cells which are not used
+    Clean,
+    /// Disconnect all register inputs
+    DisconnectRegisters,
+    /// Disconnect wires based on greedy arc set heuristic, creating a DAG
+    DisconnectArcSet,
+    /// Rename wires and instances that are part of the feedback arc set (prefixed with "arc_")
+    MarkArcSet,
+    /// Rename wires and instances sequentially 0, 1, ...
+    RenameNets,
+    /// Report the number of strongly connected components
+    ReportSccs,
+    /// Report the longest path in the netlist
+    ReportDepth,
+    /// Mark the node names of cells along the critical path (prefixed with "crit_")
+    MarkCriticalPath);
 
 /// Netlist optimization debugging tool
 #[derive(Parser, Debug)]

src/pass.rs

@@ -37,13 +37,28 @@ pub trait Pass {
 }
 
 /// Register all these passes in an enum for clap args
+///
+/// # Example
+/// ```
+/// use eqmap::register_passes;
+/// use eqmap::netlist::PrimitiveCell;
+/// use eqmap::pass::PrintVerilog;
+/// // This defines a enum called `Passes` with unit variants.
+/// // They operate on netlists containing `PrimitiveCell` cells.
+/// register_passes!(PrimitiveCell;
+///   /// A dummy pass that emits the Verilog of the netlist.
+///   PrintVerilog);
+/// ```
 #[macro_export]
 macro_rules! register_passes {
-    ($i:ty ; $($pass:ident),+ $(,)?) => {
+    ($i:ty ; $($(#[$meta:meta])* $pass:ident),+ $(,)?) => {
         /// Enum containing all registered passes for argument parsing.
         #[derive(Debug, Clone, Copy, PartialEq, Eq, clap::ValueEnum)]
         pub enum Passes {
-            $($pass),+
+            $(
+                $(#[$meta])*
+                $pass
+            ),+
         }
 
         impl std::fmt::Display for Passes {