Added functions to the BPy Text object for positioning the cursor and inserting text. It seems Text.write() actually inserts *then* moves to the end of the buffer, so it doesn't really append as it says in the docs. However, with these new functions both appending and inserting can be achieved.

source/blender/python/api2_2x/Text.c

@@ -91,8 +91,11 @@ static PyObject *Text_getFilename( BPy_Text * self );
 static PyObject *Text_getNLines( BPy_Text * self );
 static PyObject *Text_clear( BPy_Text * self );
 static PyObject *Text_write( BPy_Text * self, PyObject * value );
+static PyObject *Text_insert( BPy_Text * self, PyObject * value );
 static PyObject *Text_set( BPy_Text * self, PyObject * args );
 static PyObject *Text_asLines( BPy_Text * self );
+static PyObject *Text_getCursorPos( BPy_Text * self );
+static PyObject *Text_setCursorPos( BPy_Text * self, PyObject * args );
 
 /*****************************************************************************/
 /* Python BPy_Text methods table:                                            */
@@ -111,10 +114,16 @@ static PyMethodDef BPy_Text_methods[] = {
 	 "() - Clear Text buffer"},
 	{"write", ( PyCFunction ) Text_write, METH_O,
 	 "(line) - Append string 'str' to Text buffer"},
+	{"insert", ( PyCFunction ) Text_insert, METH_O,
+	 "(line) - Insert string 'str' to Text buffer at cursor location"},
 	{"set", ( PyCFunction ) Text_set, METH_VARARGS,
 	 "(name, val) - Set attribute 'name' to value 'val'"},
 	{"asLines", ( PyCFunction ) Text_asLines, METH_NOARGS,
 	 "() - Return text buffer as a list of lines"},
+	{"getCursorPos", ( PyCFunction ) Text_getCursorPos, METH_NOARGS,
+	 "() - Return cursor position as (row, col) tuple"},
+	{"setCursorPos", ( PyCFunction ) Text_setCursorPos, METH_VARARGS,
+	 "(row, col) - Set the cursor position to (row, col)"},
 	{NULL, NULL, 0, NULL}
 };
 
@@ -416,6 +425,26 @@ static PyObject *Text_write( BPy_Text * self, PyObject * value )
 	Py_RETURN_NONE;
 }
 
+static PyObject *Text_insert( BPy_Text * self, PyObject * value )
+{
+	char *str = PyString_AsString(value);
+	int oldstate;
+
+	if( !self->text )
+		return EXPP_ReturnPyObjError( PyExc_RuntimeError,
+					      "This object isn't linked to a Blender Text Object" );
+
+	if( !str )
+		return EXPP_ReturnPyObjError( PyExc_TypeError,
+					      "expected string argument" );
+
+	oldstate = txt_get_undostate(  );
+	txt_insert_buf( self->text, str );
+	txt_set_undostate( oldstate );
+
+	Py_RETURN_NONE;
+}
+
 static PyObject *Text_asLines( BPy_Text * self )
 {
 	TextLine *line;
@@ -442,6 +471,46 @@ static PyObject *Text_asLines( BPy_Text * self )
 	return list;
 }
 
+static PyObject *Text_getCursorPos( BPy_Text * self )
+{
+	Text *text;
+	TextLine *linep;
+	int row, col;
+
+	text = self->text;
+	if( !text )
+		return EXPP_ReturnPyObjError( PyExc_RuntimeError,
+					      "This object isn't linked to a Blender Text Object" );
+
+	for (row=0,linep=text->lines.first; linep!=text->curl; linep=linep->next)
+		row++;
+	col= text->curc;
+
+	return Py_BuildValue( "ii", row, col );
+}
+
+static PyObject *Text_setCursorPos( BPy_Text * self, PyObject * args )
+{
+	int row, col;
+	int oldstate;
+
+	if(!self->text)
+		return EXPP_ReturnPyObjError(PyExc_RuntimeError,
+					      "This object isn't linked to a Blender Text Object");
+
+	if (!PyArg_ParseTuple(args, "ii", &row, &col))
+		return EXPP_ReturnPyObjError(PyExc_TypeError,
+					      "expected two ints as arguments.");
+	if (col<0) col=0;
+	if (col>self->text->curl->len) col=self->text->curl->len;
+
+	oldstate = txt_get_undostate();
+	txt_move_to(self->text, row, col, 0);
+	txt_set_undostate(oldstate);
+
+	Py_RETURN_NONE;
+}
+
 /*****************************************************************************/
 /* Function:    Text_compare                                                 */
 /* Description: This is a callback function for the BPy_Text type. It        */