1 files changed, 51 insertions, 0 deletions

diff --git a/crates/ra_ide_api/src/display.rs b/crates/ra_ide_api/src/display.rs
new file mode 100644
index 000000000..60fa72f1b
--- /dev/null
+++ b/crates/ra_ide_api/src/display.rs
@@ -0,0 +1,51 @@
+use super::*;

+use std::fmt::{self, Display};

+

+impl Display for FunctionSignature {

+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {

+        if let Some(t) = &self.visibility {

+            write!(f, "{} ", t)?;

+        }

+

+        if let Some(name) = &self.name {

+            write!(f, "fn {}", name)?;

+        }

+

+        if !self.generic_parameters.is_empty() {

+            write!(f, "<")?;

+            write_joined(f, &self.generic_parameters, ", ")?;

+            write!(f, ">")?;

+        }

+

+        write!(f, "(")?;

+        write_joined(f, &self.parameters, ", ")?;

+        write!(f, ")")?;

+

+        if let Some(t) = &self.ret_type {

+            write!(f, " -> {}", t)?;

+        }

+

+        if !self.where_predicates.is_empty() {

+            write!(f, "\nwhere ")?;

+            write_joined(f, &self.where_predicates, ",\n      ")?;

+        }

+

+        Ok(())

+    }

+}

+

+fn write_joined<T: Display>(

+    f: &mut fmt::Formatter,

+    items: impl IntoIterator<Item = T>,

+    sep: &str,

+) -> fmt::Result {

+    let mut first = true;

+    for e in items {

+        if !first {

+            write!(f, "{}", sep)?;

+        }

+        first = false;

+        write!(f, "{}", e)?;

+    }

+    Ok(())

+}