FEATURE: Improvements to format expression printing.

src/ast/printer/mod.rs

@@ -248,21 +248,21 @@ where
                 self.render_expr(&_def.message)?;
             }
             Expression::Format(_def) => {
-                self.w
+                write!(self.w, "\"{}\"", Self::escape_quotes(&_def.template))?;
-                    .write(Self::escape_quotes(&_def.template).as_bytes())?;
                 write!(self.w, " % ")?;
                 match _def.args {
                     FormatArgs::Single(ref e) => {
                         self.render_expr(e)?;
                     }
                     FormatArgs::List(ref es) => {
-                        self.w.write("(".as_bytes())?;
+                        self.w.write("(\n".as_bytes())?;
                         self.curr_indent += self.indent;
                         let indent = self.make_indent();
+                        let mut prefix = "";
                         for e in es.iter() {
-                            self.w.write(indent.as_bytes())?;
+                            write!(self.w, "{}{}", prefix, indent)?;
                             self.render_expr(e)?;
-                            self.w.write("\n".as_bytes())?;
+                            prefix = ",\n";
                         }
                         self.curr_indent -= self.indent;
                         self.w.write(")".as_bytes())?;

src/ast/printer/test.rs

@@ -333,3 +333,29 @@ fn test_func_expr_single_arg_printing() {
     assert!(printer.err.is_none());
     assert_eq!(String::from_utf8(buffer).unwrap(), format!("{}\n", input));
 }
+
+#[test]
+fn test_format_expr_single_arg_printing() {
+    let input = "\"what? @{item.foo}\" % {
+  foo = 1,
+};";
+    let stmts = assert_parse(input);
+    let mut buffer: Vec<u8> = Vec::new();
+    let mut printer = AstPrinter::new(2, &mut buffer);
+    printer.render(&stmts);
+    assert!(printer.err.is_none());
+    assert_eq!(String::from_utf8(buffer).unwrap(), format!("{}\n", input));
+}
+
+#[test]
+fn test_format_expr_list_arg_printing() {
+    let input = "\"what? @ @\" % (
+  1,
+  2);";
+    let stmts = assert_parse(input);
+    let mut buffer: Vec<u8> = Vec::new();
+    let mut printer = AstPrinter::new(2, &mut buffer);
+    printer.render(&stmts);
+    assert!(printer.err.is_none());
+    assert_eq!(String::from_utf8(buffer).unwrap(), format!("{}\n", input));
+}