From 8a2d25247f69f891784a0828ed958269bf751e4b Mon Sep 17 00:00:00 2001
From: joe-conigliaro <joe-conigliaro@users.noreply.github.com>
Date: Sun, 7 Jul 2019 09:22:47 +1000
Subject: [PATCH] submodules

---
 compiler/main.v                          | 16 +++++++++++++---
 compiler/parser.v                        | 16 +++++++++++++++-
 compiler/tests/submodule_test.v          |  5 +++++
 vlib/{ => encoding}/base64/base64.v      |  0
 vlib/{ => encoding}/base64/base64_test.v |  2 +-
 5 files changed, 34 insertions(+), 5 deletions(-)
 create mode 100644 compiler/tests/submodule_test.v
 rename vlib/{ => encoding}/base64/base64.v (100%)
 rename vlib/{ => encoding}/base64/base64_test.v (99%)

diff --git a/compiler/main.v b/compiler/main.v
index c423a02f80..69aca8003c 100644
--- a/compiler/main.v
+++ b/compiler/main.v
@@ -717,7 +717,7 @@ fn (v mut V) add_user_v_files() {
 	// Parse lib imports
 	if v.pref.build_mode == .default_mode {
 		for i := 0; i < v.table.imports.len; i++ {
-			pkg := v.table.imports[i]
+			pkg := v.module_path(v.table.imports[i])
 			vfiles := v.v_files_from_dir('$TmpPath/vlib/$pkg')
 			// Add all imports referenced by these libs
 			for file in vfiles {
@@ -730,7 +730,7 @@ fn (v mut V) add_user_v_files() {
 		// TODO this used to crash compiler?
 		// for pkg in v.table.imports {
 		for i := 0; i < v.table.imports.len; i++ {
-			pkg := v.table.imports[i]
+			pkg := v.module_path(v.table.imports[i])
 			idir := os.getwd()
 			mut import_path := '$idir/$pkg'
 			if(!os.file_exists(import_path)) {
@@ -749,7 +749,8 @@ fn (v mut V) add_user_v_files() {
 		println(v.table.imports)
 	}
 	// Only now add all combined lib files
-	for pkg in v.table.imports {
+	for _pkg in v.table.imports {
+		pkg := v.module_path(_pkg)
 		idir := os.getwd()
 		mut module_path := '$idir/$pkg'
 		// If we are in default mode, we don't parse vlib .v files, but header .vh files in
@@ -790,6 +791,15 @@ fn get_arg(joined_args, arg, def string) string {
 	return res
 }
 
+fn (v &V) module_path(pkg string) string {
+	// submodule support
+	if pkg.contains('.') {
+		// return pkg.replace('.', path_sep)
+		return pkg.replace('.', '/')
+	}
+	return pkg
+}
+
 fn (v &V) log(s string) {
 	if !v.pref.is_verbose {
 		return
diff --git a/compiler/parser.v b/compiler/parser.v
index e8e345fcce..7a73a7b791 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -289,7 +289,21 @@ fn (p mut Parser) import_statement() {
 	if p.tok != NAME {
 		p.error('bad import format')
 	}
-	pkg := p.lit.trim_space()
+	mut pkg := p.lit.trim_space()
+	// submodule support
+	// limit depth to 4 for now
+	max_module_depth := 4
+	mut depth := 1
+	for p.peek() == DOT {
+		p.next() // SKIP DOT
+		p.next() // SUBMODULE
+		submodule := p.lit.trim_space()
+		pkg = pkg + '.' + submodule
+		depth++
+		if depth > max_module_depth {
+			panic('Sorry. Module depth of $max_module_depth exceeded: $pkg ($submodule is too deep).')
+		}
+	}
 	p.next()
 	p.fgenln(' ' + pkg)
 	// Make sure there are no duplicate imports
diff --git a/compiler/tests/submodule_test.v b/compiler/tests/submodule_test.v
new file mode 100644
index 0000000000..896e24bfd6
--- /dev/null
+++ b/compiler/tests/submodule_test.v
@@ -0,0 +1,5 @@
+import encoding.base64
+
+pub fn test_submodules() {
+    assert base64.decode('c3VibW9kdWxlcyBhcmUgd29ya2luZyE=') == 'submodules are working!'
+}
diff --git a/vlib/base64/base64.v b/vlib/encoding/base64/base64.v
similarity index 100%
rename from vlib/base64/base64.v
rename to vlib/encoding/base64/base64.v
diff --git a/vlib/base64/base64_test.v b/vlib/encoding/base64/base64_test.v
similarity index 99%
rename from vlib/base64/base64_test.v
rename to vlib/encoding/base64/base64_test.v
index e9a92a7fff..f2ce9f4b0d 100644
--- a/vlib/base64/base64_test.v
+++ b/vlib/encoding/base64/base64_test.v
@@ -1,4 +1,4 @@
-import base64
+import encoding.base64
 
 struct testpair {
 	decoded string