checker: check fn main(); vfmt: fix for{}, module and module comments

cmd/v/v.v

@@ -103,7 +103,7 @@ fn main() {
 		}
 		else {}
 	}
-	if command in ['run', 'build'] || command.ends_with('.v') || os.exists(command) {
+	if command in ['run', 'build-module'] || command.ends_with('.v') || os.exists(command) {
 		//println('command')
 		//println(prefs.path)
 		builder.compile(command, prefs)
@@ -179,7 +179,7 @@ fn parse_args(args []string) (&pref.Preferences, string) {
 		res.path = args[command_pos+1]
 		res.run_args = args[command_pos+1..]
 	}
-	if command == 'build' {
+	if command == 'build-module' {
 		res.build_mode = .build_module
 		res.path = args[command_pos+1]
 	}

vlib/v/checker/checker.v

@@ -60,6 +60,17 @@ pub fn (c mut Checker) check_files(ast_files []ast.File) {
 	for file in ast_files {
 		c.check(file)
 	}
+	// Make sure fn main is defined in non lib builds
+	if c.pref.build_mode == .build_module {
+		return
+	}
+	for i, f in c.table.fns {
+		if f.name == 'main' {
+			return
+		}
+	}
+	eprintln('function `main` is undeclared in the main module')
+	exit(1)
 }
 
 pub fn (c mut Checker) struct_init(struct_init mut ast.StructInit) table.Type {

vlib/v/fmt/fmt.v

@@ -36,7 +36,7 @@ pub fn fmt(file ast.File, table &table.Table) string {
 		file: file
 	}
 	f.cur_mod = 'main'
-	for stmt in file.stmts {
+	for i, stmt in file.stmts {
 		f.stmt(stmt)
 	}
 	// for comment in file.comments { println('$comment.line_nr $comment.text')	}
@@ -279,7 +279,11 @@ fn (f mut Fmt) stmt(node ast.Stmt) {
 		ast.ForStmt {
 			f.write('for ')
 			f.expr(it.cond)
+			if it.is_inf {
+				f.writeln('{')
+			} else {
 				f.writeln(' {')
+			}
 			f.stmts(it.stmts)
 			f.writeln('}')
 		}

vlib/v/gen/cgen.v

@@ -466,6 +466,7 @@ fn (g mut Gen) stmt(node ast.Stmt) {
 		ast.InterfaceDecl {
 			g.writeln('// interface')
 		}
+		ast.Module {}
 		ast.Return {
 			if g.defer_stmts.len > 0 {
 				g.write_defer_stmts()

vlib/v/parser/parser.v

@@ -68,7 +68,7 @@ pub fn parse_file(path string, table &table.Table, comments_mode scanner.Comment
 		scanner: scanner.new_scanner_file(path, comments_mode)
 		table: table
 		file_name: path
-		file_name_dir: os.dir( path )
+		file_name_dir: os.dir(path)
 		pref: pref
 		scope: &ast.Scope{
 			start_pos: 0
@@ -78,12 +78,16 @@ pub fn parse_file(path string, table &table.Table, comments_mode scanner.Comment
 	}
 	// comments_mode: comments_mode
 	p.read_first_token()
-	// module decl
-	module_decl := if p.tok.kind == .key_module { p.module_decl() } else { ast.Module{
-			name: 'main'
-		} }
-	p.mod = module_decl.name
-	p.builtin_mod = p.mod == 'builtin'
+	for p.tok.kind == .comment {
+		mut stmt := ast.Stmt{}		// TODO sum type << bug
+		com := p.comment()
+		stmt = com
+		stmts << stmt
+	}
+	mut mstmt := ast.Stmt{}
+	module_decl := p.module_decl()
+	mstmt = module_decl
+	stmts << mstmt
 	// imports
 	/*
 	mut imports := []ast.Import
@@ -250,6 +254,10 @@ fn (p mut Parser) check_name() string {
 }
 
 pub fn (p mut Parser) top_stmt() ast.Stmt {
+	if p.fileis('mmm.v') {
+		print('!!stmt()')
+		println(p.tok.kind.str())
+	}
 	match p.tok.kind {
 		.key_pub {
 			match p.peek_tok.kind {
@@ -283,9 +291,6 @@ pub fn (p mut Parser) top_stmt() ast.Stmt {
 		.key_interface {
 			return p.interface_decl()
 		}
-		.key_module {
-			return p.module_decl()
-		}
 		.key_import {
 			node := p.import_stmt()
 			p.ast_imports << node
@@ -859,7 +864,7 @@ pub fn (p mut Parser) expr(precedence int) ast.Expr {
 				left: node
 				right: right
 				op: tok.kind
-				pos:pos
+				pos: pos
 			}
 		} else if p.tok.kind.is_infix() {
 			node = p.infix_expr(node)
@@ -1348,7 +1353,7 @@ fn (p mut Parser) array_init() ast.ArrayInit {
 	last_pos := p.tok.position()
 	len := last_pos.pos - first_pos.pos
 	pos := token.Position{
-		line_nr: first_pos.line_nr,
+		line_nr: first_pos.line_nr
 		pos: first_pos.pos
 		len: len
 	}
@@ -1403,10 +1408,14 @@ fn (p mut Parser) parse_number_literal() ast.Expr {
 }
 
 fn (p mut Parser) module_decl() ast.Module {
+	mut name := 'main'
+	if p.tok.kind == .key_module {
 		p.check(.key_module)
-	mod := p.check_name()
-	full_mod := p.table.qualify_module(mod, p.file_name)
+		name = p.check_name()
+	}
+	full_mod := p.table.qualify_module(name, p.file_name)
 	p.mod = full_mod
+	p.builtin_mod = p.mod == 'builtin'
 	return ast.Module{
 		name: full_mod
 	}
@@ -1918,8 +1927,6 @@ fn (p mut Parser) enum_decl() ast.EnumDecl {
 	return ast.EnumDecl{
 		name: name
 		is_pub: is_pub
-		// vals: vals
-		// default_exprs: default_exprs
 		fields: fields
 	}
 }