chore: More idiomatic display impls for expressions (#3601)

Signed-off-by: Robert Kruszewski <[email protected]>

Author: robert3005

vortex-expr/src/field.rs

@@ -1,17 +1,12 @@
 use std::fmt::Display;
 
+use itertools::Itertools;
 use vortex_dtype::FieldNames;
 
 pub struct DisplayFieldNames<'a>(pub &'a FieldNames);
 
 impl Display for DisplayFieldNames<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        for (i, field) in self.0.iter().enumerate() {
-            if i > 0 {
-                write!(f, ", ")?;
-            }
-            field.fmt(f)?
-        }
-        Ok(())
+        write!(f, "{}", self.0.iter().format(", "))
     }
 }

vortex-expr/src/merge.rs

@@ -47,16 +47,12 @@ pub fn merge(
 
 impl Display for Merge {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str("{")?;
-        self.values
-            .iter()
-            .format_with(", ", |expr, f| f(expr))
-            .fmt(f)?;
-        f.write_str("}")?;
-        if Nullability::Nullable == self.nullability {
-            f.write_str("?")?;
-        }
-        Ok(())
+        write!(
+            f,
+            "merge({}){}",
+            self.values.iter().format(", "),
+            self.nullability
+        )
     }
 }
 

vortex-expr/src/not.rs

@@ -29,8 +29,7 @@ impl Not {
 
 impl Display for Not {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "!")?;
-        self.child.fmt(f)
+        write!(f, "!{}", self.child)
     }
 }
 

vortex-expr/src/pack.rs

@@ -105,23 +105,20 @@ pub fn pack(
 
 impl Display for Pack {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str("{")?;
-        self.names
-            .iter()
-            .zip(&self.values)
-            .format_with(", ", |(name, expr), f| f(&format_args!("{name}: {expr}")))
-            .fmt(f)?;
-        f.write_str("}")?;
-        if Nullability::Nullable == self.nullability {
-            f.write_str("?")?;
-        }
-        Ok(())
+        write!(
+            f,
+            "pack({{{}}}){}",
+            self.names
+                .iter()
+                .zip(&self.values)
+                .format_with(", ", |(name, expr), f| f(&format_args!("{name}: {expr}"))),
+            self.nullability
+        )
     }
 }
 
 #[cfg(feature = "proto")]
 pub(crate) mod proto {
-
     use vortex_error::{VortexResult, vortex_bail};
     use vortex_proto::expr::kind;
     use vortex_proto::expr::kind::Kind;

vortex-expr/src/scope.rs

@@ -56,7 +56,7 @@ impl std::fmt::Display for Identifier {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             Identifier::Identity => write!(f, ""),
-            Identifier::Other(v) => write!(f, "{}", v),
+            Identifier::Other(v) => write!(f, "{v}"),
         }
     }
 }