Replace `try!` with `try?`.

8 files changed, 38 insertions, 46 deletions

diff --git a/doc/docs/doc/README.md b/doc/docs/doc/README.md
index 1d9c8ad..c0312f7 100755
--- a/doc/docs/doc/README.md
+++ b/doc/docs/doc/README.md
@@ -1516,21 +1516,21 @@ catch err
 </pre>
 </YueDisplay>
 
-### Try!
+### Try?
 
-`try!` is a more concise error handling syntax that omit the boolean status from the `try` statement, and it will return the result from the try block when success, otherwise return nil instead of error object.
+`try?` is a simplified use for error handling syntax that omit the boolean status from the `try` statement, and it will return the result from the try block when success, return nil instead of error object otherwise.
 
 ```moonscript
-a, b, c = try! func!
+a, b, c = try? func!
 
 -- with nil coalescing operator
-a = (try! func!) ?? "default"
+a = (try? func!) ?? "default"
 
 -- as function argument
-f try! func!
+f try? func!
 
 -- with catch block
-f try!
+f try?
   print 123
   func!
 catch e
@@ -1539,16 +1539,16 @@ catch e
 ```
 <YueDisplay>
 <pre>
-a, b, c = try! func!
+a, b, c = try? func!
 
 -- with nil coalescing operator
-a = (try! func!) ?? "default"
+a = (try? func!) ?? "default"
 
 -- as function argument
-f try! func!
+f try? func!
 
 -- with catch block
-f try!
+f try?
   print 123
   func!
 catch e
diff --git a/doc/docs/zh/doc/README.md b/doc/docs/zh/doc/README.md
index 0fa1fed..b4e594c 100755
--- a/doc/docs/zh/doc/README.md
+++ b/doc/docs/zh/doc/README.md
@@ -1516,19 +1516,19 @@ catch err
 
 ### 错误处理简化
 
-`try!` 是 `try` 的简化语法，它不再返回 `try` 语句的布尔状态，并在成功时直接返回 `try` 代码块的结果，失败时返回 `nil` 值而非错误对象。
+`try?` 是 `try` 的功能简化语法，它不再返回 `try` 语句的布尔状态，并在成功时直接返回 `try` 代码块的结果，失败时返回 `nil` 值而非错误对象。
 
 ```moonscript
-a, b, c = try! func!
+a, b, c = try? func!
 
 -- 与空值合并运算符一起使用
-a = (try! func!) ?? "default"
+a = (try? func!) ?? "default"
 
 -- 作为函数参数
-f try! func!
+f try? func!
 
 -- 带 catch 块的 try!
-f try!
+f try?
   print 123
   func!
 catch e
@@ -1537,16 +1537,16 @@ catch e
 ```
 <YueDisplay>
 <pre>
-a, b, c = try! func!
+a, b, c = try? func!
 
 -- 与空值合并运算符一起使用
-a = (try! func!) ?? "default"
+a = (try? func!) ?? "default"
 
 -- 作为函数参数
-f try! func!
+f try? func!
 
 -- 带 catch 块的 try!
-f try!
+f try?
   print 123
   func!
 catch e
diff --git a/spec/inputs/try_catch.yue b/spec/inputs/try_catch.yue
index f2583b7..6c29a52 100644
--- a/spec/inputs/try_catch.yue
+++ b/spec/inputs/try_catch.yue
@@ -71,19 +71,19 @@ f = ->
 
         do
                 local func
-                a, b, c = try! func!
+                a, b, c = try? func!
         
         do
-                a, b, c = try! func!
+                a, b, c = try? func!
 
         do
-                a = (try! func!) ?? "default"
+                a = (try? func!) ?? "default"
 
         do
-                f try! func!
+                f try? func!
         
         do
-                f try!
+                f try?
                         print 123
                         func!
                 catch e
@@ -165,19 +165,19 @@ do
 
         do
                 local func
-                a, b, c = try! func!
+                a, b, c = try? func!
         
         do
-                a, b, c = try! func!
+                a, b, c = try? func!
 
         do
-                a = (try! func!) ?? "default"
+                a = (try? func!) ?? "default"
 
         do
-                f try! func!
+                f try? func!
         
         do
-                f try!
+                f try?
                         print 123
                         func!
                 catch e
diff --git a/src/yuescript/yue_ast.cpp b/src/yuescript/yue_ast.cpp
index be10859..c4f133b 100644
--- a/src/yuescript/yue_ast.cpp
+++ b/src/yuescript/yue_ast.cpp
@@ -609,15 +609,12 @@ std::string CatchBlock_t::to_string(void* ud) const {
         info->popScope();
         return line + '\n' + blockStr;
 }
-std::string Omit_t::to_string(void*) const {
-        return "!"s;
-}
 std::string Try_t::to_string(void* ud) const {
         auto info = reinterpret_cast<YueFormat*>(ud);
         str_list temp;
         temp.emplace_back("try"s);
-        if (omit) {
-                temp.back() += '!';
+        if (eop) {
+                temp.back() += eop->to_string(ud);
         }
         if (func.is<Exp_t>()) {
                 temp.back() += (" "s + func->to_string(ud));
diff --git a/src/yuescript/yue_ast.h b/src/yuescript/yue_ast.h
index 393f374..6bdc31b 100644
--- a/src/yuescript/yue_ast.h
+++ b/src/yuescript/yue_ast.h
@@ -383,14 +383,11 @@ AST_NODE(CatchBlock)
         AST_MEMBER(CatchBlock, &err, &block)
 AST_END(CatchBlock)
 
-AST_LEAF(Omit)
-AST_END(Omit)
-
 AST_NODE(Try)
-        ast_ptr<false, Omit_t> omit;
+        ast_ptr<false, ExistentialOp_t> eop;
         ast_sel<true, Block_t, Exp_t> func;
         ast_ptr<false, CatchBlock_t> catchBlock;
-        AST_MEMBER(Try, &omit, &func, &catchBlock)
+        AST_MEMBER(Try, &eop, &func, &catchBlock)
 AST_END(Try)
 
 AST_NODE(Comprehension)
diff --git a/src/yuescript/yue_compiler.cpp b/src/yuescript/yue_compiler.cpp
index 35745f2..4bac51b 100644
--- a/src/yuescript/yue_compiler.cpp
+++ b/src/yuescript/yue_compiler.cpp
@@ -78,7 +78,7 @@ static std::unordered_set<std::string> Metamethods = {
         "close"s // Lua 5.4
 };
 
-const std::string_view version = "0.28.6"sv;
+const std::string_view version = "0.28.7"sv;
 const std::string_view extension = "yue"sv;
 
 class CompileError : public std::logic_error {
@@ -2332,7 +2332,7 @@ private:
                         }
                         case id<Try_t>(): {
                                 auto tryNode = static_cast<Try_t*>(value);
-                                if (tryNode->omit) {
+                                if (tryNode->eop) {
                                         auto assignList = assignment->expList.get();
                                         std::string preDefine = getPreDefineLine(assignment);
                                         transformTry(tryNode, out, ExpUsage::Assignment, assignList);
@@ -10055,7 +10055,7 @@ private:
 
         void transformTry(Try_t* tryNode, str_list& out, ExpUsage usage, ExpList_t* assignList = nullptr) {
                 auto x = tryNode;
-                if (tryNode->omit && usage == ExpUsage::Assignment) {
+                if (tryNode->eop && usage == ExpUsage::Assignment) {
                         str_list rets;
                         pushScope();
                         auto okVar = getUnusedName("_ok_"sv);
@@ -10080,7 +10080,7 @@ private:
                         transformAssignment(assignment, out);
                         return;
                 }
-                if (tryNode->omit && usage != ExpUsage::Common) {
+                if (tryNode->eop && usage != ExpUsage::Common) {
                         auto okVar = getUnusedName("_ok_"sv);
                         auto code = "do\n\t"s + okVar + ", ... = try nil\n\t... if "s + okVar;
                         auto doNode = toAst<Do_t>(code, x);
diff --git a/src/yuescript/yue_parser.cpp b/src/yuescript/yue_parser.cpp
index 2b0aea8..0cf7f05 100644
--- a/src/yuescript/yue_parser.cpp
+++ b/src/yuescript/yue_parser.cpp
@@ -501,9 +501,8 @@ YueParser::YueParser() {
                 return true;
         });
 
-        Omit = expr('!');
         CatchBlock = line_break >> *space_break >> check_indent_match >> space >> key("catch") >> space >> Variable >> space >> in_block;
-        Try = key("try") >> -Omit >> space >> (in_block | Exp) >> -CatchBlock;
+        Try = key("try") >> -ExistentialOp >> space >> (in_block | Exp) >> -CatchBlock;
 
         list_value =
                 and_(
diff --git a/src/yuescript/yue_parser.h b/src/yuescript/yue_parser.h
index 99f3d45..0d9db19 100644
--- a/src/yuescript/yue_parser.h
+++ b/src/yuescript/yue_parser.h
@@ -347,7 +347,6 @@ private:
         AST_RULE(ForEach);
         AST_RULE(Do);
         AST_RULE(CatchBlock);
-        AST_RULE(Omit);
         AST_RULE(Try);
         AST_RULE(Comprehension);
         AST_RULE(CompValue);