From 6d4f2146b89d9d43eedb5326d0411a698b9e4ae9 Mon Sep 17 00:00:00 2001
From: Jonathan Turner <probata@hotmail.com>
Date: Thu, 2 Jul 2009 17:22:12 +0000
Subject: [PATCH] Added function guards

---
 chaiscript/chaiscript_eval.hpp   | 36 +++++++++++++++++++++++++-------
 chaiscript/chaiscript_parser.hpp | 11 ++++++++--
 2 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/chaiscript/chaiscript_eval.hpp b/chaiscript/chaiscript_eval.hpp
index 755bb80..8d374ce 100644
--- a/chaiscript/chaiscript_eval.hpp
+++ b/chaiscript/chaiscript_eval.hpp
@@ -315,7 +315,7 @@ namespace chaiscript
                 }
                 catch(const dispatchkit::dispatch_error &e){
                     ss.set_stack(prev_stack);
-                    throw EvalError("Engine error: " + std::string(e.what()) + " on '" + node->children[0]->text + "'", node->children[0]);
+                    throw EvalError("Engine error: " + std::string(e.what()) + " with function '" + node->children[0]->text + "'", node->children[0]);
                 }
                 catch(ReturnValue &rv) {
                     ss.set_stack(prev_stack);
@@ -485,19 +485,41 @@ namespace chaiscript
             case (Token_Type::Def) : {
                 std::vector<std::string> param_names;
 
-                if ((node->children.size() > 1) && (node->children[1]->identifier == Token_Type::Arg_List)) {
+                if ((node->children.size() > 2) && (node->children[1]->identifier == Token_Type::Arg_List)) {
                     for (i = 0; i < node->children[1]->children.size(); ++i) {
                         param_names.push_back(node->children[1]->children[i]->text);
                     }
-                    ss.register_function(boost::shared_ptr<dispatchkit::Proxy_Function>(
-                          new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children.back(), param_names, _1), node->children[1]->children.size())), node->children[0]->text);
+
+                    if (node->children.size() > 3) {
+                        //Guarded function
+                        boost::shared_ptr<dispatchkit::Dynamic_Proxy_Function> guard = boost::shared_ptr<dispatchkit::Dynamic_Proxy_Function>
+                            (new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children[2], param_names, _1), node->children[1]->children.size()));
+
+                        ss.register_function(boost::shared_ptr<dispatchkit::Proxy_Function>(
+                              new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children.back(), param_names, _1), node->children[1]->children.size(),
+                              guard)), node->children[0]->text);
+
+                    }
+                    else {
+                        ss.register_function(boost::shared_ptr<dispatchkit::Proxy_Function>(
+                              new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children.back(), param_names, _1), node->children[1]->children.size())), node->children[0]->text);
+                    }
                 }
                 else {
                     //no parameters
-                    ss.register_function(boost::shared_ptr<dispatchkit::Proxy_Function>(
-                            //no parameters
-                          new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children.back(), param_names, _1), 0)), node->children[0]->text);
 
+                    if (node->children.size() > 2) {
+                        boost::shared_ptr<dispatchkit::Dynamic_Proxy_Function> guard = boost::shared_ptr<dispatchkit::Dynamic_Proxy_Function>
+                            (new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children[1], param_names, _1), 0));
+
+                        ss.register_function(boost::shared_ptr<dispatchkit::Proxy_Function>(
+                              new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children.back(), param_names, _1), 0,
+                              guard)), node->children[0]->text);
+                    }
+                    else {
+                        ss.register_function(boost::shared_ptr<dispatchkit::Proxy_Function>(
+                          new dispatchkit::Dynamic_Proxy_Function(boost::bind(&eval_function<Eval_System>, boost::ref(ss), node->children.back(), param_names, _1), 0)), node->children[0]->text);
+                    }
                 }
             }
             break;
diff --git a/chaiscript/chaiscript_parser.hpp b/chaiscript/chaiscript_parser.hpp
index e79642b..5d3c1e2 100644
--- a/chaiscript/chaiscript_parser.hpp
+++ b/chaiscript/chaiscript_parser.hpp
@@ -682,6 +682,13 @@ namespace chaiscript
 
                 while (Eol());
 
+                if (Char(':')) {
+                    if (!Expression()) {
+                        throw Parse_Error("Missing guard expression for function", File_Position(line, col), filename);
+                    }
+                }
+
+                while (Eol());
                 if (!Block()) {
                     throw Parse_Error("Incomplete function definition", File_Position(line, col), filename);
                 }
@@ -870,7 +877,7 @@ namespace chaiscript
             std::string::iterator prev_pos = input_pos;
 
             unsigned int prev_stack_top = match_stack.size();
-            if (Id(true)) {
+            if (Id(true) || Id_Literal()) {
                 retval = true;
                 bool has_more = true;
 
@@ -1021,7 +1028,7 @@ namespace chaiscript
 
         bool Value() {
             if (Var_Decl() || Lambda() || Id_Fun_Array() || Num(true) || Prefix() || Quoted_String(true) || Single_Quoted_String(true) ||
-                    Paren_Expression() || Inline_Container() || Id_Literal()) {
+                    Paren_Expression() || Inline_Container()) {
                 return true;
             }
             else {