From b9309ce12b06e77f04aeafe927c20a245101d7e4 Mon Sep 17 00:00:00 2001
From: Jeremy Wall <jeremy@marzhillstudios.com>
Date: Wed, 2 Oct 2019 19:53:20 -0500
Subject: [PATCH] FIX: Don't print an extraneous new line on fmt.

Fixes: #49
---
 src/ast/printer/mod.rs  |  15 ++++--
 src/ast/printer/test.rs | 102 ++++++++++++++++++++--------------------
 2 files changed, 61 insertions(+), 56 deletions(-)

diff --git a/src/ast/printer/mod.rs b/src/ast/printer/mod.rs
index 61875bd..7cd400c 100644
--- a/src/ast/printer/mod.rs
+++ b/src/ast/printer/mod.rs
@@ -473,9 +473,11 @@ where
                 write!(self.w, "{{\n")?;
                 self.curr_indent += self.indent_size;
                 let indent = self.make_indent();
+                let mut prefix_newline = false;
                 for stmt in _def.statements.iter() {
                     write!(self.w, "{}", indent)?;
-                    self.render_stmt(stmt)?;
+                    self.render_stmt(stmt, prefix_newline)?;
+                    prefix_newline = true;
                 }
                 self.curr_indent -= self.indent_size;
                 write!(self.w, "}}")?;
@@ -532,8 +534,11 @@ where
         Ok(())
     }
 
-    pub fn render_stmt(&mut self, stmt: &Statement) -> std::io::Result<()> {
+    pub fn render_stmt(&mut self, stmt: &Statement, prefix_newline: bool) -> std::io::Result<()> {
         // All statements start at the beginning of a line.
+        if prefix_newline {
+            write!(self.w, "\n")?;
+        }
         let line = stmt.pos().line;
         self.render_comment_if_needed(line)?;
         match stmt {
@@ -557,14 +562,16 @@ where
                 self.render_expr(&_expr)?;
             }
         };
-        write!(self.w, ";\n\n")?;
+        write!(self.w, ";\n")?;
         self.last_line = line;
         Ok(())
     }
 
     pub fn render(&mut self, stmts: &Vec<Statement>) -> std::io::Result<()> {
+        let mut prefix_newline = false;
         for v in stmts {
-            self.render_stmt(v)?;
+            self.render_stmt(v, prefix_newline)?;
+            prefix_newline = true;
         }
         let comment_line = self.comment_group_lines.first().cloned();
         if let Some(last_comment_line) = comment_line {
diff --git a/src/ast/printer/test.rs b/src/ast/printer/test.rs
index 2e6bba9..67c4010 100644
--- a/src/ast/printer/test.rs
+++ b/src/ast/printer/test.rs
@@ -33,67 +33,67 @@ fn print_to_buffer(input: &str) -> String {
 #[test]
 fn test_simple_value_printing() {
     let input = "1;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_simple_selector_printing() {
     let input = "foo.bar.quux;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_simple_quoted_printing() {
     let input = "\"foo\";";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_escaped_quoted_printing() {
     let input = "\"f\\\\o\\\"o\";";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_empty_tuple_printing() {
     let input = "{};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_empty_list_printing() {
     let input = "[];";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_non_empty_tuple_printing() {
     let input = "{\n  foo = 1,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_nested_empty_tuple_printing() {
     let input = "{\n  foo = {},\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_list_nested_empty_tuple_printing() {
     let input = "[\n  {},\n];";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_nested_non_empty_tuple_printing() {
     let input = "{\n  foo = {\n    bar = 1,\n  },\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_nested_non_empty_list_printing() {
     let input = "[\n  [\n    1,\n  ],\n];";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -101,80 +101,80 @@ fn test_simple_quoted_field_tuple_printing() {
     let input = "{\n  \"foo\" = {\n    bar = 1,\n  },\n};";
     assert_eq!(
         print_to_buffer(input),
-        format!("{}\n\n", "{\n  foo = {\n    bar = 1,\n  },\n};")
+        format!("{}\n", "{\n  foo = {\n    bar = 1,\n  },\n};")
     );
 }
 
 #[test]
 fn test_special_quoted_field_tuple_printing() {
     let input = "{\n  \"foo bar\" = {\n    bar = 1,\n  },\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_let_statement_printing() {
     let input = "let tpl = {\n  \"foo bar\" = {\n    bar = 1,\n  },\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_call_expr_printing() {
     let input = "call(\n  foo,\n  bar,\n);";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_call_expr_one_arg_printing() {
     let input = "call(foo);";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_copy_expr_printing() {
     let input = "copy{\n  foo = 1,\n  bar = 2,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_copy_expr_one_arg_printing() {
     let input = "copy{\n  foo = 1,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_out_expr_printing() {
     let input = "out json {\n  foo = 1,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_select_expr_no_default_printing() {
     let input = "select true, {\n  true = 1,\n  false = 2,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_select_expr_with_default_printing() {
     let input = "select true, 3, {\n  true = 1,\n  false = 2,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_not_expr_printing() {
     let input = "not true;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_fail_expr_printing() {
     let input = "fail \"AHHh\";";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_trace_expr_printing() {
     let input = "TRACE \"AHHh\";";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -189,9 +189,8 @@ fn test_module_no_out_expr_printing() {
     memory_size = mod.mem,
     cpu_count = mod.cpu,
   };
-
 };";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -206,9 +205,8 @@ fn test_module_with_out_expr_printing() {
     memory_size = mod.mem,
     cpu_count = mod.cpu,
   };
-
 };";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -217,7 +215,7 @@ fn test_func_expr_printing() {
   foo = foo,
   bar = bar,
 };";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -225,7 +223,7 @@ fn test_func_expr_single_arg_printing() {
     let input = "let f = func (foo) => {
   foo = foo,
 };";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -233,7 +231,7 @@ fn test_format_expr_single_arg_printing() {
     let input = "\"what? @{item.foo}\" % {
   foo = 1,
 };";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -241,37 +239,37 @@ fn test_format_expr_list_arg_printing() {
     let input = "\"what? @ @\" % (
   1,
   2);";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_statement_with_comment_printing() {
     let input = "// add 1 + 1\n1 + 1;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_statement_with_comment_printing_groups() {
     let input = "// add 1\n// and 1\n1 + 1;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_statement_with_comment_printing_multiple_groups() {
     let input = "\n// group 1\n// more group 1\n\n// group 2\n// more group 2\n1 + 1;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input.trim()));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input.trim()));
 }
 
 #[test]
 fn test_statement_with_comment_printing_comments_at_end() {
     let input = "// group 1\n1 + 1;\n\n// group 2\n\n";
-    assert_eq!(print_to_buffer(input), format!("{}\n", input.trim()));
+    assert_eq!(print_to_buffer(input), input.replace("\n\n", "\n"));
 }
 
 #[test]
 fn test_tuple_expression_with_embedded_comment() {
     let input = "{\n  foo = bar,\n  // a comment\n  bar = foo,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
@@ -285,7 +283,7 @@ fn test_tuple_expression_with_embedded_comment_same_line() {
   foo = bar,
   bar = foo,
 };";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", expected));
+    assert_eq!(print_to_buffer(input), format!("{}\n", expected));
 }
 
 #[test]
@@ -293,7 +291,7 @@ fn test_tuple_expression_with_embedded_comment_mid_field_expr() {
     let input = "{\n  foo = bar,\n  bar =\n// a comment\n   foo\n};";
     assert_eq!(
         print_to_buffer(input),
-        "{\n  foo = bar,\n  // a comment\n  bar = foo,\n};\n\n"
+        "{\n  foo = bar,\n  // a comment\n  bar = foo,\n};\n"
     );
 }
 
@@ -302,57 +300,57 @@ fn test_tuple_expression_with_embedded_comment_and_mid_field_expr() {
     let input = "{\n  foo = bar,\n// a comment\n  bar =\n// another comment\n   foo\n};";
     assert_eq!(
         print_to_buffer(input),
-        "{\n  foo = bar,\n  // a comment\n  // another comment\n  bar = foo,\n};\n\n"
+        "{\n  foo = bar,\n  // a comment\n  // another comment\n  bar = foo,\n};\n"
     );
 }
 
 #[test]
 fn test_list_expression_with_embedded_comment() {
     let input = "[\n  bar,\n  // a comment\n  foo,\n];";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_binary_expression_with_embedded_comment() {
     let input = "true == \n// false is not true\nfalse;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_empty_call_expression_with_comment() {
     let input = "// a comment\nmyfunc();";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_call_expression_with_embedded_comment_in_args() {
     let input = "// a comment\nmyfunc(\n  arg1,\n  // another comment\n  arg2,\n);";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_copy_expression_with_embedded_comment_in_args() {
     let input = "// a comment\nmyfunc{\n  foo = arg1,\n  // another comment\n  bar = arg2,\n};";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_trace_expression_with_embedded_comment() {
     let input = "// a comment\nTRACE \n// another comment\nfoo;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_fail_expression_with_embedded_comment() {
     let input = "// a comment\nfail \n// another comment\nfoo;";
-    assert_eq!(print_to_buffer(input), format!("{}\n\n", input));
+    assert_eq!(print_to_buffer(input), format!("{}\n", input));
 }
 
 #[test]
 fn test_format_expression_with_embedded_comment() {
     let input = "// a comment\n\"@(item.bar)\" % \n// another comment\nfoo;";
     let output = print_to_buffer(input);
-    assert_eq!(output, format!("{}\n\n", input.trim()));
+    assert_eq!(output, format!("{}\n", input.trim()));
 }
 
 #[test]
@@ -360,7 +358,7 @@ fn test_filter_func_operator_expression_with_embedded_comment() {
     //let input = "// a comment\nfilter(foo, bar);";
     let input = "// a comment\nfilter(\n  // another comment\n  foo,\n  // one more\n  bar);";
     let output = print_to_buffer(input);
-    assert_eq!(output, format!("{}\n\n", input.trim()));
+    assert_eq!(output, format!("{}\n", input.trim()));
 }
 
 #[test]
@@ -373,7 +371,7 @@ fn test_reduce_func_operator_expression_with_embedded_comment() {
   // and the last
   target);";
     let output = print_to_buffer(input);
-    assert_eq!(output, format!("{}\n\n", input.trim()));
+    assert_eq!(output, format!("{}\n", input.trim()));
 }
 
 #[test]
@@ -381,7 +379,7 @@ fn test_map_func_operator_expression_with_embedded_comment() {
     //let input = "// a comment\nfilter(foo, bar);";
     let input = "// a comment\nmap(\n  // another comment\n  foo,\n  // one more\n  bar);";
     let output = print_to_buffer(input);
-    assert_eq!(output, format!("{}\n\n", input.trim()));
+    assert_eq!(output, format!("{}\n", input.trim()));
 }
 
 #[test]
@@ -389,5 +387,5 @@ fn test_grouped_expression_with_embedded_comment() {
     //let input = "// a comment\nfilter(foo, bar);";
     let input = "// a comment\n(\n  // a comment\n  foo\n);";
     let output = print_to_buffer(input);
-    assert_eq!(output, format!("{}\n\n", input.trim()));
+    assert_eq!(output, format!("{}\n", input.trim()));
 }