all: fix current module in build-module mode

vlib/v/builder/cc.v

@@ -176,8 +176,8 @@ fn (mut v Builder) cc() {
 			verror('-fast is only supported on Linux right now')
 		}
 	}
-	if !v.pref.is_shared && v.pref.build_mode != .build_module &&
+	if !v.pref.is_shared && v.pref.build_mode != .build_module && os.user_os() == 'windows' &&
-		os.user_os() == 'windows' && !v.pref.out_name.ends_with('.exe') {
+		!v.pref.out_name.ends_with('.exe') {
 		v.pref.out_name += '.exe'
 	}
 	// linux_host := os.user_os() == 'linux'
@@ -199,13 +199,15 @@ fn (mut v Builder) cc() {
 	}
 	if v.pref.build_mode == .build_module {
 		// Create the modules & out directory if it's not there.
-		mut out_dir := if v.pref.path.starts_with('vlib') { '$pref.default_module_path${os.path_separator}cache$os.path_separator$v.pref.path' } else { '$pref.default_module_path$os.path_separator$v.pref.path' }
+		mut out_dir := if v.pref.path.starts_with('vlib') { '$pref.default_module_path${os.path_separator}cache$os.path_separator$v.pref.path' } else { '$pref.default_module_path${os.path_separator}cache/$v.pref.path' }
 		pdir := out_dir.all_before_last(os.path_separator)
 		if !os.is_dir(pdir) {
 			os.mkdir_all(pdir)
 		}
 		v.pref.out_name = '${out_dir}.o' // v.out_name
 		println('Building ${v.pref.out_name}...')
+		// println('v.table.imports:')
+		// println(v.table.imports)
 	}
 	debug_mode := v.pref.is_debug
 	mut debug_options := '-g3'
@@ -290,7 +292,14 @@ fn (mut v Builder) cc() {
 			os.system('$vexe build module vlib${os.path_separator}builtin')
 		}
 		*/
+		// TODO add `.unique()` to V arrays
+		mut unique_imports := []string{cap: v.table.imports.len}
 		for imp in v.table.imports {
+			if imp !in unique_imports {
+				unique_imports << imp
+			}
+		}
+		for imp in unique_imports {
 			if imp.contains('vweb') {
 				continue
 			}
@@ -385,8 +394,8 @@ fn (mut v Builder) cc() {
 	}
 	// Without these libs compilation will fail on Linux
 	// || os.user_os() == 'linux'
-	if !v.pref.is_bare && v.pref.build_mode != .build_module &&
+	if !v.pref.is_bare && v.pref.build_mode != .build_module && v.pref.os in
-		v.pref.os in [.linux, .freebsd, .openbsd, .netbsd, .dragonfly, .solaris, .haiku] {
+		[.linux, .freebsd, .openbsd, .netbsd, .dragonfly, .solaris, .haiku] {
 		linker_flags << '-lm'
 		linker_flags << '-lpthread'
 		// -ldl is a Linux only thing. BSDs have it in libc.
@@ -529,7 +538,8 @@ fn (mut v Builder) cc() {
 				println('install upx with `brew install upx`')
 			}
 			$if linux {
-				println('install upx\n' + 'for example, on Debian/Ubuntu run `sudo apt install upx`')
+				println('install upx\n' +
+					'for example, on Debian/Ubuntu run `sudo apt install upx`')
 			}
 			$if windows {
 				// :)

vlib/v/gen/cgen.v

@@ -132,7 +132,7 @@ pub fn cgen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 		fn_decl: 0
 		autofree: true
 		indent: -1
-		module_built: pref.path.after('vlib/')
+		module_built: pref.path.after('vlib/').replace('/', '.')
 	}
 	for mod in g.table.modules {
 		g.inits[mod] = strings.new_builder(100)
@@ -740,6 +740,7 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 				if !node.name.starts_with(g.module_built + '.') && node.mod != g.module_built.after('/') {
 					// Skip functions that don't have to be generated
 					// for this module.
+					println('skip bm $node.name mode=$node.mod module_built=$g.module_built')
 					skip = true
 				}
 				if g.is_builtin_mod && g.module_built == 'builtin' {

vlib/v/gen/fn.v

@@ -7,6 +7,9 @@ import v.ast
 import v.table
 import v.util
 
+pub fn kek_cheburek() {
+}
+
 fn (mut g Gen) gen_fn_decl(it ast.FnDecl, skip bool) {
 	if it.language == .c {
 		// || it.no_body {
@@ -277,9 +280,8 @@ fn (mut g Gen) call_expr(node ast.CallExpr) {
 		g.write('$styp $tmp_opt = ')
 	}
 	if node.is_method && !node.is_field {
-		if node.name == 'writeln' && g.pref.experimental &&
+		if node.name == 'writeln' && g.pref.experimental && node.args.len > 0 && node.args[0].expr is
-			node.args.len > 0 && node.args[0].expr is ast.StringInterLiteral &&
+			ast.StringInterLiteral && g.table.get_type_symbol(node.receiver_type).name == 'strings.Builder' {
-			g.table.get_type_symbol(node.receiver_type).name == 'strings.Builder' {
 			g.string_inter_literal_sb_optimized(node)
 		} else {
 			g.method_call(node)

vlib/v/parser/module.v

@@ -9,6 +9,7 @@ pub fn (p &Parser) known_import(mod string) bool {
 }
 
 fn (p &Parser) prepend_mod(name string) string {
+	// println('prepend_mod() name=$name p.mod=$p.mod expr_mod=$p.expr_mod')
 	if p.expr_mod != '' {
 		return p.expr_mod + '.' + name
 	}

vlib/v/parser/parser.v

@@ -1342,7 +1342,20 @@ fn (mut p Parser) module_decl() ast.Module {
 		}
 		module_pos = module_pos.extend(pos)
 	}
-	full_mod := p.table.qualify_module(name, p.file_name)
+	mut full_mod := p.table.qualify_module(name, p.file_name)
+	if p.pref.build_mode == .build_module && !full_mod.contains('.') {
+		// A hack to make building vlib modules work
+		// `v build-module v.gen` will result in `full_mod = "gen"`, not "v.gen",
+		// because the module being built
+		// is not imported.
+		// So here we fetch the name of the module by looking at the path that's being built.
+		word := p.pref.path.after('/')
+		if full_mod == word {
+			full_mod = p.pref.path.after('vlib/').replace('/', '.')
+			// println('new full mod =$full_mod')
+		}
+		// println('file_name=$p.file_name path=$p.pref.path')
+	}
 	p.mod = full_mod
 	p.builtin_mod = p.mod == 'builtin'
 	return ast.Module{

vlib/v/table/table.v

@@ -489,6 +489,7 @@ pub fn (t &Table) mktyp(typ Type) Type {
 // this is not optimal
 pub fn (table &Table) qualify_module(mod, file_path string) string {
 	for m in table.imports {
+		//if m.contains('gen') { println('qm=$m') }
 		if m.contains('.') && m.contains(mod) {
 			m_parts := m.split('.')
 			m_path := m_parts.join(os.path_separator)