fmt: keep newlines between toplevel stmts (#8383)

vlib/v/fmt/fmt.v

@@ -61,14 +61,10 @@ pub fn fmt(file ast.File, table &table.Table, is_debug bool) string {
 	}
 	f.process_file_imports(file)
 	f.set_current_module_name('main')
-	for stmt in file.stmts {
-		if stmt is ast.Import {
-			// Just remember the position of the imports for now
-			f.import_pos = f.out.len
-			// f.imports(f.file.imports)
-		}
-		f.stmt(stmt)
-	}
+	// As these are toplevel stmts, the indent increase done in f.stmts() has to be compensated
+	f.indent--
+	f.stmts(file.stmts)
+	f.indent++
 	// for comment in file.comments { println('$comment.line_nr $comment.text')	}
 	f.imports(f.file.imports) // now that we have all autoimports, handle them
 	res := f.out.str().trim_space() + '\n'
@@ -271,20 +267,39 @@ pub fn (f Fmt) imp_stmt_str(imp ast.Import) string {
 	return '$imp.mod$imp_alias_suffix'
 }
 
-pub fn (mut f Fmt) stmts(stmts []ast.Stmt) {
-	f.indent++
-	mut prev_line_nr := 0
-	if stmts.len >= 1 {
-		prev_pos := stmts[0].position()
-		prev_line_nr = util.imax(prev_pos.line_nr, prev_pos.last_line)
+fn (mut f Fmt) should_insert_newline_before_stmt(stmt ast.Stmt, prev_stmt ast.Stmt) bool {
+	prev_line_nr := prev_stmt.position().last_line
+	// The stmt either has or shouldn't have a newline before
+	if stmt.position().line_nr - prev_line_nr <= 1 || f.out.last_n(2) == '\n\n' {
+		return false
 	}
+	// Imports are handled special hence they are ignored here
+	if stmt is ast.Import || prev_stmt is ast.Import {
+		return false
+	}
+	// Attributes are not respected in the stmts position, so we have to check it manually
+	if stmt is ast.StructDecl {
+		if stmt.attrs.len > 0 && stmt.attrs[0].pos.line_nr - prev_line_nr <= 1 {
+			return false
+		}
+	}
+	if stmt is ast.FnDecl {
+		if stmt.attrs.len > 0 && stmt.attrs[0].pos.line_nr - prev_line_nr <= 1 {
+			return false
+		}
+	}
+	return true
+}
+
+pub fn (mut f Fmt) stmts(stmts []ast.Stmt) {
+	mut prev_stmt := if stmts.len > 0 { stmts[0] } else { ast.Stmt{} }
+	f.indent++
 	for stmt in stmts {
-		if stmt.position().line_nr - prev_line_nr > 1 {
+		if f.should_insert_newline_before_stmt(stmt, prev_stmt) {
 			f.out.writeln('')
 		}
 		f.stmt(stmt)
-		prev_pos := stmt.position()
-		prev_line_nr = util.imax(prev_pos.line_nr, prev_pos.last_line)
+		prev_stmt = stmt
 	}
 	f.indent--
 }
@@ -362,6 +377,8 @@ pub fn (mut f Fmt) stmt(node ast.Stmt) {
 		}
 		ast.Import {
 			// Imports are handled after the file is formatted, to automatically add necessary modules
+			// Just remember the position of the imports for now
+			f.import_pos = f.out.len
 			// f.imports(f.file.imports)
 		}
 		ast.InterfaceDecl {

vlib/v/fmt/tests/comment_after_import_expected.vv

@@ -1,5 +1,6 @@
 import semver
 
 // as semver
+
 fn main() {
 }

vlib/v/fmt/tests/hashstmts_keep.vv

@@ -0,0 +1,8 @@
+// comment above HashStmts
+#flag linux -lsdl2
+#include "stdio.h"
+
+// comment between with newlines around
+
+#include "header.h"
+#include "sqlite3.h"

vlib/v/fmt/tests/import_keep.vv

@@ -0,0 +1,5 @@
+// import time This should be commented out
+import os
+import rand
+
+// another comment after imports

vlib/v/fmt/tests/newlines_keep.vv

@@ -0,0 +1,19 @@
+// Module with attribute
+[manualfree]
+module websocket
+
+fn main() {}
+
+// This should stay between both functions
+
+fn x() {}
+
+// doc comment above an attributed function
+[inline]
+fn y_with_attr() {
+}
+
+// doc comment above an attributed struct
+[typedef]
+struct Foo {
+}

vlib/v/fmt/tests/types_expected.vv

@@ -13,6 +13,7 @@ type MyInt = int
 pub type Abc = f32
 
 // Fn type decl
+
 type EmptyFn = fn ()
 
 type OneArgFn = fn (i int)

vlib/v/parser/comptime.v

@@ -16,7 +16,7 @@ const (
 
 // // #include, #flag, #v
 fn (mut p Parser) hash() ast.HashStmt {
-	mut pos := p.prev_tok.position()
+	pos := p.tok.position()
 	val := p.tok.lit
 	kind := val.all_before(' ')
 	p.next()

vlib/v/parser/if_match.v

@@ -15,12 +15,11 @@ fn (mut p Parser) if_expr(is_comptime bool) ast.IfExpr {
 		p.inside_ct_if_expr = was_inside_ct_if_expr
 	}
 	p.inside_if_expr = true
-	mut pos := if is_comptime {
+	mut pos := p.tok.position()
+	if is_comptime {
 		p.inside_ct_if_expr = true
 		p.next() // `$`
-		p.prev_tok.position().extend(p.tok.position())
-	} else {
-		p.tok.position()
+		pos = p.prev_tok.position().extend(p.tok.position())
 	}
 	mut branches := []ast.IfBranch{}
 	mut has_else := false

vlib/v/parser/parser.v

@@ -204,7 +204,11 @@ pub fn (mut p Parser) parse() ast.File {
 	}
 	// module
 	module_decl := p.module_decl()
+	if module_decl.is_skipped {
+		stmts.insert(0, ast.Stmt(module_decl))
+	} else {
 		stmts << module_decl
+	}
 	// imports
 	for {
 		if p.tok.kind == .key_import {
@@ -513,8 +517,10 @@ pub fn (mut p Parser) top_stmt() ast.Stmt {
 				return p.struct_decl()
 			}
 			.dollar {
+				if_expr := p.if_expr(true)
 				return ast.ExprStmt{
-					expr: p.if_expr(true)
+					expr: if_expr
+					pos: if_expr.pos
 				}
 			}
 			.hash {
@@ -1753,6 +1759,7 @@ fn (mut p Parser) parse_number_literal() ast.Expr {
 
 fn (mut p Parser) module_decl() ast.Module {
 	mut module_attrs := []table.Attr{}
+	mut attrs_pos := p.tok.position()
 	if p.tok.kind == .lsbr {
 		p.attributes()
 		module_attrs = p.attrs
@@ -1788,7 +1795,7 @@ fn (mut p Parser) module_decl() ast.Module {
 				return mod_node
 			}
 		}
-		module_pos = module_pos.extend(name_pos)
+		module_pos = attrs_pos.extend(name_pos)
 	}
 	full_name := util.qualify_module(name, p.file_name)
 	p.mod = full_name

vlib/v/scanner/scanner.v

@@ -154,10 +154,11 @@ pub fn (mut s Scanner) set_current_tidx(cidx int) {
 fn (mut s Scanner) new_token(tok_kind token.Kind, lit string, len int) token.Token {
 	cidx := s.tidx
 	s.tidx++
+	line_offset := if tok_kind == .hash { 0 } else { 1 }
 	return token.Token{
 		kind: tok_kind
 		lit: lit
-		line_nr: s.line_nr + 1
+		line_nr: s.line_nr + line_offset
 		pos: s.pos - len + 1
 		len: len
 		tidx: cidx