add goto statement support.

6 files changed, 96 insertions, 12 deletions

diff --git a/README.md b/README.md
index 319e821..c8159c4 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,8 @@ f!
 
 The original Moonscript language 0.5.0 support can be found in the `0.5.0` branch. Moonscript with new features is in the master branch. Here are the new features introduced in MoonPlus.
 
+* Add goto statement support.
+
 * Add macro functions.
 ```Moonscript
 -- file 'macro.moon'
diff --git a/spec/inputs/goto.moon b/spec/inputs/goto.moon
new file mode 100644
index 0000000..3410ca3
--- /dev/null
+++ b/spec/inputs/goto.moon
@@ -0,0 +1,41 @@
+do
+        a = 0
+        ::start::
+        a += 1
+        goto done if a == 5
+        goto start
+        ::done::
+
+do
+        for z = 1, 10 for y = 1, 10 for x = 1, 10
+                if x^2 + y^2 == z^2
+                        print 'found a Pythagorean triple:', x, y, z
+                        goto done
+        ::done::
+
+do
+        for z = 1, 10
+                for y = 1, 10 for x = 1, 10
+                                if x^2 + y^2 == z^2
+                                        print 'found a Pythagorean triple:', x, y, z
+                                        print 'now trying next z...'
+                                        goto zcontinue
+                ::zcontinue::
+
+do
+        ::redo::
+        for x = 1, 10 for y = 1, 10
+                if not f x, y then goto continue
+                if not g x, y then goto skip
+                if not h x, y then goto redo
+                ::continue::
+        ::skip::
+
+do
+        for x in *t
+                if x % 2 == 0
+                        print 'list has even number'
+                        goto has
+        print 'list lacks even number'
+        ::has::
+
diff --git a/src/MoonP/moon_ast.h b/src/MoonP/moon_ast.h
index 0725bda..3f9ce79 100644
--- a/src/MoonP/moon_ast.h
+++ b/src/MoonP/moon_ast.h
@@ -46,6 +46,11 @@ AST_NODE(Variable)
         AST_MEMBER(Variable, &name)
 AST_END(Variable)
 
+AST_NODE(LabelName)
+        ast_ptr<true, Name_t> name;
+        AST_MEMBER(LabelName, &name)
+AST_END(LabelName)
+
 AST_NODE(LuaKeyword)
         ast_ptr<true, Name_t> name;
         AST_MEMBER(LuaKeyword, &name)
@@ -142,6 +147,16 @@ AST_NODE(Import)
         AST_MEMBER(Import, &content)
 AST_END(Import)
 
+AST_NODE(Label)
+        ast_ptr<true, LabelName_t> label;
+        AST_MEMBER(Label, &label)
+AST_END(Label)
+
+AST_NODE(Goto)
+        ast_ptr<true, LabelName_t> label;
+        AST_MEMBER(Goto, &label)
+AST_END(Goto)
+
 class FnArgsDef_t;
 
 AST_LEAF(fn_arrow_back)
@@ -650,7 +665,7 @@ AST_END(BreakLoop)
 AST_NODE(Statement)
         ast_sel<true, Import_t, While_t, For_t, ForEach_t,
                 Return_t, Local_t, Global_t, Export_t, Macro_t, BreakLoop_t,
-                Backcall_t, ExpListAssign_t> content;
+                Label_t, Goto_t, Backcall_t, ExpListAssign_t> content;
         ast_ptr<false, statement_appendix_t> appendix;
         AST_MEMBER(Statement, &content, &appendix)
 AST_END(Statement)
diff --git a/src/MoonP/moon_compiler.cpp b/src/MoonP/moon_compiler.cpp
index c176c01..b89f6d1 100644
--- a/src/MoonP/moon_compiler.cpp
+++ b/src/MoonP/moon_compiler.cpp
@@ -43,7 +43,7 @@ inline std::string s(std::string_view sv) {
 }
 
 const char* moonScriptVersion() {
-        return "0.5.0-r0.3.4";
+        return "0.5.0-r0.3.5";
 }
 
 // name of table stored in lua registry
@@ -750,6 +750,8 @@ private:
                         case id<Export_t>(): transformExport(static_cast<Export_t*>(content), out); break;
                         case id<Macro_t>(): transformMacro(static_cast<Macro_t*>(content), out, false); break;
                         case id<BreakLoop_t>(): transformBreakLoop(static_cast<BreakLoop_t*>(content), out); break;
+                        case id<Label_t>(): transformLabel(static_cast<Label_t*>(content), out); break;
+                        case id<Goto_t>(): transformGoto(static_cast<Goto_t*>(content), out); break;
                         case id<ExpListAssign_t>(): {
                                 auto expListAssign = static_cast<ExpListAssign_t*>(content);
                                 if (expListAssign->action) {
@@ -4997,6 +4999,14 @@ private:
                 _buf << indent() << "break"sv << nll(breakLoop);
                 out.push_back(clearBuf());
         }
+
+        void transformLabel(Label_t* label, str_list& out) {
+                out.push_back(indent() + s("::"sv) + _parser.toString(label->label) + s("::"sv) + nll(label));
+        }
+
+        void transformGoto(Goto_t* gotoNode, str_list& out) {
+                out.push_back(indent() + s("goto "sv) + _parser.toString(gotoNode->label) + nll(gotoNode));
+        }
 };
 
 const std::string MoonCompilerImpl::Empty;
diff --git a/src/MoonP/moon_parser.cpp b/src/MoonP/moon_parser.cpp
index c8a3a23..872e30e 100644
--- a/src/MoonP/moon_parser.cpp
+++ b/src/MoonP/moon_parser.cpp
@@ -15,18 +15,18 @@ using namespace std::string_view_literals;
 
 std::unordered_set<std::string> LuaKeywords = {
         "and", "break", "do", "else", "elseif",
-        "end", "false", "for", "function", "if",
-        "in", "local", "nil", "not", "or",
-        "repeat", "return", "then", "true", "until",
-        "while"
+        "end", "false", "for", "function", "goto",
+        "if", "in", "local", "nil", "not",
+        "or", "repeat", "return", "then", "true",
+        "until", "while"
 };
 
 std::unordered_set<std::string> Keywords = {
         "and", "break", "do", "else", "elseif",
-        "end", "false", "for", "function", "if",
-        "in", "local", "nil", "not", "or",
-        "repeat", "return", "then", "true", "until",
-        "while", // Lua keywords
+        "end", "false", "for", "function", "goto",
+        "if", "in", "local", "nil", "not",
+        "or", "repeat", "return", "then", "true",
+        "until", "while", // Lua keywords
         "as", "class", "continue", "export", "extends",
         "from", "global", "import", "macro", "switch",
         "unless", "using", "when", "with" // Moon keywords
@@ -85,6 +85,14 @@ MoonParser::MoonParser() {
                 return isValid;
         });
 
+        LabelName = pl::user(Name, [](const item_t& item) {
+                State* st = reinterpret_cast<State*>(item.user_data);
+                for (auto it = item.begin; it != item.end; ++it) st->buffer += static_cast<char>(*it);
+                auto isValid = LuaKeywords.find(st->buffer) == LuaKeywords.end();
+                st->buffer.clear();
+                return isValid;
+        });
+
         LuaKeyword = pl::user(Name, [](const item_t& item) {
                 State* st = reinterpret_cast<State*>(item.user_data);
                 for (auto it = item.begin; it != item.end; ++it) st->buffer += static_cast<char>(*it);
@@ -191,9 +199,14 @@ MoonParser::MoonParser() {
 
         Import = key("import") >> (ImportAs | ImportFrom);
 
+        Label = Space >> expr("::") >> LabelName >> expr("::");
+
+        Goto = key("goto") >> Space >> LabelName;
+
         BreakLoop = (expr("break") | expr("continue")) >> not_(AlphaNum);
 
         Return = key("return") >> -ExpListLow;
+
         WithExp = ExpList >> -Assign;
 
         With = key("with") >> DisableDo >> ensure(WithExp, PopDo) >> -key("do") >> Body;
@@ -527,8 +540,8 @@ MoonParser::MoonParser() {
         Statement = (
                 Import | While | For | ForEach |
                 Return | Local | Global | Export |
-                Macro | Space >> BreakLoop |
-                Backcall | ExpListAssign
+                Macro | Space >> BreakLoop | Label |
+                Goto | Backcall | ExpListAssign
         ) >> Space >>
         -statement_appendix;
 
diff --git a/src/MoonP/moon_parser.h b/src/MoonP/moon_parser.h
index 4d67696..cea14fa 100644
--- a/src/MoonP/moon_parser.h
+++ b/src/MoonP/moon_parser.h
@@ -182,6 +182,7 @@ private:
         AST_RULE(Num)
         AST_RULE(Name)
         AST_RULE(Variable)
+        AST_RULE(LabelName)
         AST_RULE(LuaKeyword)
         AST_RULE(self)
         AST_RULE(self_name)
@@ -201,6 +202,8 @@ private:
         AST_RULE(ImportFrom)
         AST_RULE(ImportAs)
         AST_RULE(Import)
+        AST_RULE(Label)
+        AST_RULE(Goto)
         AST_RULE(fn_arrow_back)
         AST_RULE(Backcall)
         AST_RULE(ExpListLow)