Refactor add merge separator constant

src/hvmc_net/mutual_recursion.rs

@@ -1,4 +1,7 @@
-use crate::diagnostics::{Diagnostics, WarningType, ERR_INDENT_SIZE};
+use crate::{
+  diagnostics::{Diagnostics, WarningType, ERR_INDENT_SIZE},
+  term::transform::definition_merge::MERGE_SEPARATOR,
+};
 use hvmc::ast::{Book, Tree};
 use indexmap::{IndexMap, IndexSet};
 use std::fmt::Debug;
@@ -157,9 +160,9 @@ impl Debug for Graph {
 fn combinations_from_merges(cycle: Vec<Ref>) -> Vec<Vec<Ref>> {
   let mut combinations: Vec<Vec<Ref>> = vec![vec![]];
   for r#ref in cycle {
-    if let Some(index) = r#ref.find("_$_") {
+    if let Some(index) = r#ref.find(MERGE_SEPARATOR) {
       let (left, right) = r#ref.split_at(index);
-      let right = &right[3 ..]; // skip "_$_"
+      let right = &right[MERGE_SEPARATOR.len() ..]; // skip merge separator
       let mut new_combinations = Vec::new();
       for combination in &combinations {
         let mut left_comb = combination.clone();

src/term/transform/definition_merge.rs

@@ -4,6 +4,8 @@ use indexmap::{IndexMap, IndexSet};
 use itertools::Itertools;
 use std::collections::BTreeMap;
 
+pub const MERGE_SEPARATOR: &str = "_$_";
+
 impl Book {
   /// Merges definitions that have the same structure into one definition.
   /// Expects variables to be linear.
@@ -28,7 +30,7 @@ impl Book {
 
     for (term, equal_defs) in equal_terms {
       // def1_$_def2_$_def3
-      let new_name = Name::new(equal_defs.iter().join("_$_"));
+      let new_name = Name::new(equal_defs.iter().join(MERGE_SEPARATOR));
 
       // Builtin origin takes precedence
       let builtin = equal_defs.iter().any(|nam| self.defs[nam].builtin);

tests/golden_tests.rs

@@ -349,7 +349,7 @@ fn mutual_recursion() {
       ..DiagnosticsConfig::new(Severity::Allow, true)
     };
     let mut book = do_parse_book(code, path)?;
-    let mut opts =  CompileOpts::light();
+    let mut opts = CompileOpts::light();
     opts.merge = true;
     let res = compile_book(&mut book, opts, diagnostics_cfg, None)?;
     Ok(format!("{}{}", res.diagnostics, res.core_book))