Lua improvements - Mark Gossage patch #1295168

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@7476 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Lib/lua/std_string.i

@@ -0,0 +1,122 @@
+/***********************************************************************
+ * std_string.i
+ *
+ *     std::string typemaps for LUA
+ *
+ * Author : Mark Gossage (mark@gossage.cjb.net)
+ ************************************************************************/
+
+%{
+	#include <string>
+%}
+/*
+Only std::string and const std::string& are typemaped
+they are converted to the Lua strings automatically
+
+eg.
+
+std::string test_value(std::string x) {
+   return x;
+}
+
+can be used as
+
+s="hello world"
+s2=test_value(s)
+assert(s==s2)
+
+*/
+%typemap(in,checkfn="lua_isstring") std::string
+%{$1 = (char*)lua_tostring(L, $input);%}
+
+%typemap(out) std::string
+%{  lua_pushstring(L,$1.c_str()); SWIG_arg++;%}
+
+%typemap(in,checkfn="lua_isstring")	const std::string& (std::string temp)
+%{temp=(char*)lua_tostring(L, $input); $1=&temp;%}
+%typemap(out) const std::string&
+%{  lua_pushstring(L,$1->c_str()); SWIG_arg++;%}
+
+%typemap(throws) std::string,const std::string&
+%{lua_pushstring(L,$1.c_str());
+SWIG_fail; %}
+
+/*
+std::string& can be wrappered, but you must inform SWIG if it is in or out
+
+eg:
+void fn(std::string& str);
+Is this an in/out/inout value?
+
+Therefore you need the usual
+%apply (std::string& INOUT) {(std::string& str)};
+or
+%apply std::string& INOUT {std::string& str};
+typemaps to tell SWIG what to do.
+*/
+
+%typemap(in) std::string &INPUT=const std::string &;
+%typemap(in, numinputs=0) std::string &OUTPUT (std::string temp)
+%{ $1 = &temp; %}
+%typemap(argout) std::string &OUTPUT
+%{  lua_pushstring(L,$1.c_str()); SWIG_arg++;%}
+%typemap(in) std::string &INOUT =const std::string &;
+%typemap(argout) std::string &INOUT = std::string &OUTPUT;
+
+/*
+For const std::string* and std::string* is not clear
+is this a pointer or an array?
+
+Therefore just leaving it as is
+(there is some rough code below which could be used if needed
+
+// SWIG wraps const ref's as pointer
+// typemaps to deal with this and const ptrs
+%typemap(in,checkfn="lua_isstring")
+	const std::string& INPUT(std::string temp),
+	const std::string* INPUT(std::string temp)
+%{temp=(char*)lua_tostring(L, $input); $1=&temp;%}
+%typemap(out) const std::string&, const std::string*
+%{  lua_pushstring(L,$1->c_str()); SWIG_arg++;%}
+
+// the non-const pointer version
+%typemap(in) std::string *INPUT=const std::string *INPUT;
+%typemap(in, numinputs=0) std::string *OUTPUT (std::string temp)
+%{ $1 = &temp; %}
+%typemap(argout) std::string *OUTPUT
+%{  lua_pushstring(L,$1->c_str()); SWIG_arg++;%}
+%typemap(in) std::string *INOUT = std::string *INPUT;
+%typemap(argout) std::string *INOUT = std::string *OUTPUT;
+
+*/
+
+/*
+A really cut down version of the string class
+
+This provides basic mapping of lua strings <-> std::string
+and little else
+(the std::string has a lot of unneeded functions anyway)
+
+*/
+namespace std {
+
+    class string {
+      public:
+        string();
+        string(const char*);
+        string(const string&);
+        unsigned int size() const;
+        unsigned int length() const;
+        bool empty() const;
+        // no support for operator[]
+        const char* c_str()const;
+        const char* data()const;
+        // assign does not return a copy of this object
+        // (no point in a scripting language)
+        void assign(const char*);
+        void assign(const string&);
+        // no support for all the other features
+        // its probably better to do it in lua
+    };
+}
+