Parser: reduce backtracking for command_atom

Backtracking is reduced by left refactoring function definition and bash
command.

3 files changed, 46 insertions, 4 deletions

diff --git a/src/core/interpreter.cpp b/src/core/interpreter.cpp
index ba69143..539b9f1 100644
--- a/src/core/interpreter.cpp
+++ b/src/core/interpreter.cpp
@@ -310,6 +310,27 @@ void interpreter::define_function_arguments(scope& current_stack,
   current_stack["*"].reset(new variable("*", positional_args, true));
 }
 
+namespace
+{
+  bool check_function_name(const std::string& name)
+  {
+    using namespace boost::xpressive;
+    sregex bash_name_pattern =
+      !digit >>
+      ~(set[range('0', '9') | (set= '$', '\'', '"', '(', ')', ' ', '\n', '\r')]) >>
+      *(~(set= '$', '\'', '"', '(', ')', ' ', '\n', '\r'));
+    return regex_match(name, bash_name_pattern);
+  }
+}
+
+void interpreter::define_function(const std::string& name,
+                                  ANTLR3_MARKER body_index)
+{
+  if(!check_function_name(name))
+    throw libbash::parse_exception("illegal function name: " + name);
+  functions.insert(make_pair(name, function(*ast_stack.top(), body_index)));
+}
+
 void interpreter::call(const std::string& name,
                        const std::vector<std::string>& arguments)
 {
diff --git a/src/core/interpreter.h b/src/core/interpreter.h
index 3363ae7..801e24f 100644
--- a/src/core/interpreter.h
+++ b/src/core/interpreter.h
@@ -311,10 +311,7 @@ public:
   /// \param name the name of the function
   /// \param body_index the body index of the function
   void define_function(const std::string& name,
-                       ANTLR3_MARKER body_index)
-  {
-    functions.insert(make_pair(name, function(*ast_stack.top(), body_index)));
-  }
+                       ANTLR3_MARKER body_index);
 
   /// \brief push current AST, used for function definition
   /// \param ast the pointer to the current ast
diff --git a/src/core/tests/interpreter_test.cpp b/src/core/tests/interpreter_test.cpp
index d20697b..ecbcfd9 100644
--- a/src/core/tests/interpreter_test.cpp
+++ b/src/core/tests/interpreter_test.cpp
@@ -261,3 +261,27 @@ TEST(interpreter, undefined_function)
 
   EXPECT_THROW(walker.call("undefined", {}), libbash::runtime_exception);
 }
+
+TEST(interpreter, illegal_function_names)
+{
+  interpreter walker;
+  walker.push_current_ast(0);
+  EXPECT_THROW(walker.define_function("aa'bb", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("aa\"", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("333", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("aa$aa", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("aa(aa", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("aa)aa", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("aa aa", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("aa\naa", 0), libbash::parse_exception);
+  EXPECT_THROW(walker.define_function("aa\raa", 0), libbash::parse_exception);
+}
+
+TEST(interpreter, legal_function_names)
+{
+  interpreter walker;
+  walker.push_current_ast(0);
+  EXPECT_NO_THROW(walker.define_function("aabb", 0));
+  EXPECT_NO_THROW(walker.define_function("1abb", 0));
+  EXPECT_NO_THROW(walker.define_function("a-b", 0));
+}