feat(hydroflow_lang): Render singleton references in graphvis (#1146)

Refs: #797 #1065

docs/src/pages/playground.js

@@ -200,6 +200,7 @@ export function EditorDemo({ compileFn, examples, mermaidId }) {
     noVarnames: false,
     noPullPush: false,
     noHandoffs: false,
+    noReferences: false,
     opShortText: false,
   });
   const writeGraphConfigOnChange = (name) => {

hydroflow/tests/snapshots/surface_singleton__state_ref@graphvis_dot.snap

@@ -19,6 +19,7 @@ digraph {
     n5v1 -> n6v1
     n1v1 -> n5v1
     n4v1 -> n8v1 [color=darkgreen, style=bold]
+    n6v1 -> n4v1 [color=red]
     subgraph "cluster n1v1" {
         fillcolor="#dddddd"
         style=filled

hydroflow/tests/snapshots/surface_singleton__state_ref@graphvis_mermaid.snap

@@ -22,6 +22,7 @@ linkStyle default stroke:#aaa
 5v1-->6v1
 1v1-->5v1
 4v1==>8v1; linkStyle 5 stroke:#060
+6v1--x4v1; linkStyle 6 stroke:red
 subgraph sg_1v1 ["sg_1v1 stratum 0"]
     1v1
     5v1

hydroflow_lang/src/graph/graph_write.rs

@@ -11,7 +11,7 @@ use super::{Color, FlowProps, GraphNodeId, GraphSubgraphId, LatticeFlowType};
 
 /// Trait for writing textual representations of graphs, i.e. mermaid or dot graphs.
 #[auto_impl(&mut, Box)]
-pub trait GraphWrite {
+pub(crate) trait GraphWrite {
     /// Error type emitted by writing.
     type Err: Error;
 
@@ -34,6 +34,7 @@ pub trait GraphWrite {
         delay_type: Option<DelayType>,
         flow_props: Option<FlowProps>,
         label: Option<&str>,
+        is_reference: bool,
     ) -> Result<(), Self::Err>;
 
     /// Begin writing a subgraph.
@@ -164,6 +165,7 @@ where
         delay_type: Option<DelayType>,
         flow_props: Option<FlowProps>,
         label: Option<&str>,
+        _is_reference: bool,
     ) -> Result<(), Self::Err> {
         let src_str = format!("{:?}", src_id.data());
         let dest_str = format!("{:?}", dst_id.data());
@@ -342,6 +344,7 @@ where
         delay_type: Option<DelayType>,
         flow_props: Option<FlowProps>,
         label: Option<&str>,
+        _is_reference: bool,
     ) -> Result<(), Self::Err> {
         let lattice_flow_type = flow_props.and_then(|flow_props| flow_props.lattice_flow_type);
         let mut properties = Vec::<Cow<'static, str>>::new();

hydroflow_lang/src/graph/hydroflow_graph.rs

@@ -19,7 +19,7 @@ use super::{
     HANDOFF_NODE_STR, HYDROFLOW,
 };
 use crate::diagnostic::{Diagnostic, Level};
-use crate::graph::ops::null_write_iterator_fn;
+use crate::graph::ops::{null_write_iterator_fn, DelayType};
 use crate::graph::MODULE_BOUNDARY_NODE_STR;
 use crate::pretty_span::{PrettyRowCol, PrettySpan};
 use crate::process_singletons::postprocess_singletons;
@@ -1341,7 +1341,7 @@ impl HydroflowGraph {
     }
 
     /// Write out this `HydroflowGraph` using the given `GraphWrite`. E.g. `Mermaid` or `Dot.
-    pub fn write_graph<W>(
+    pub(crate) fn write_graph<W>(
         &self,
         mut graph_write: W,
         write_config: &WriteConfig,
@@ -1456,7 +1456,31 @@ impl HydroflowGraph {
             let delay_type = self
                 .node_op_inst(dst_id)
                 .and_then(|op_inst| (op_inst.op_constraints.input_delaytype_fn)(dst_port));
-            graph_write.write_edge(src_id, dst_id, delay_type, flow_props, label.as_deref())?;
+            graph_write.write_edge(
+                src_id,
+                dst_id,
+                delay_type,
+                flow_props,
+                label.as_deref(),
+                false,
+            )?;
+        }
+
+        // Write reference edges.
+        if !write_config.no_references {
+            for src_id in self.node_ids() {
+                for dst_id in self
+                    .node_singleton_references(src_id)
+                    .iter()
+                    .copied()
+                    .flatten()
+                {
+                    let delay_type = Some(DelayType::Stratum);
+                    let flow_props = None;
+                    let label = None;
+                    graph_write.write_edge(src_id, dst_id, delay_type, flow_props, label, true)?;
+                }
+            }
         }
 
         // Write subgraphs.
@@ -1588,6 +1612,9 @@ pub struct WriteConfig {
     /// Will not render handoffs if set.
     #[cfg_attr(feature = "debugging", arg(long))]
     pub no_handoffs: bool,
+    /// Will not render singleton references if set.
+    #[cfg_attr(feature = "debugging", arg(long))]
+    pub no_references: bool,
 
     /// Op text will only be their name instead of the whole source.
     #[cfg_attr(feature = "debugging", arg(long))]

website_playground/src/lib.rs

@@ -111,13 +111,15 @@ pub fn compile_hydroflow(
     no_varnames: bool,
     no_pull_push: bool,
     no_handoffs: bool,
+    no_references: bool,
     op_short_text: bool,
 ) -> JsValue {
     let write_config = WriteConfig {
         no_subgraphs,
         no_varnames,
         no_pull_push,
         no_handoffs,
+        no_references,
         op_short_text,
     };
 
@@ -164,13 +166,15 @@ pub fn compile_datalog(
     no_varnames: bool,
     no_pull_push: bool,
     no_handoffs: bool,
+    no_references: bool,
     op_short_text: bool,
 ) -> JsValue {
     let write_config = WriteConfig {
         no_subgraphs,
         no_varnames,
         no_pull_push,
         no_handoffs,
+        no_references,
         op_short_text,
     };