Big problem with Python functions . not knowing the sheet.

[Nindi Singh <nindi73 yahoo co uk>]

Hi

I have been wanting to add user defined functions to Python, but there has been major hurdle.
If I call a Python function with a parameter that is a range from the same sheet the function is being called 
from, I have trouble getting at the cell data. This is because to access cells I need to know the sheet. If 
the range of cells is from another sheet, there is no problem, the rangeref has a sheet attribute that I can 
query.
But if it he range is on the same sheet as the function this is NULL. 

To solve this , what I have done is written a C function that simply returns the index of this sheet. We can 
then call ths function from our python function and know which sheet the function is evaluated from.

I already had  gnumeric 1.7.0 installed on an Ubuntu box.
I downloaded the source for gnumeric from the gnumeric website and unzipped it.
I then ran 

    ./configure  --prefix=~/opt

I didn't  want to damage my existing installation, I only needed the source. configure showed up alot of 
missing libraries which I downlodaed an installed.

I then ran configure again, successfully.followed by 'make' and 'make 'install'.


The plugin adds the function 'get_EvalSheet()' to Gnumeric. In your python function you can then do something 
like this.

def MyFunc(theRange):

    if theRange.start.sheet == None:
           n = Gnumeric.functions['get_EvalSheet']()
           wb = Gnumeric.Workbooks()[0]  
           range_sheet = wb.get_sheets()[n]
    else:
           range_sheet = theRange.start.sheet
 ..........................



My Makefile

--------------------------------------------------------------------------------------------------------------------------------------
PLUGIN = GetEvalSheet

GNUMERIC_SOURCE =  -I/home/ninds/temp/gnumeric-1.7.0 \
       -I/home/ninds/temp/gnumeric-1.7.0/src
# when I downloaded the gnumeric source I unziped it at  /home/ninds/temp/
       
GNUMERIC_HEADERS = -I/home/ninds/opt/include/libspreadsheet-1-7 \
       -I/usr/include/libgoffice-0.3 
       
# I installed it at /home/ninds/opt/
GNOME_CFLAGS =  -I/usr/include/glib-2.0 \
    -I/usr/lib/glib-2.0/include \
    -I/usr/include/libxml2 \
    -I/usr/include/pango-1.0 \
    -I/usr/include/libgsf-1 
    
all :
 gcc -fPIC -shared -o $(PLUGIN).so \
       $(GNUMERIC_SOURCE)\
       $(GNUMERIC_HEADERS)\
       $(GNOME_CFLAGS) GetEvalSheet.c
        
   
-------------------------------------------------------------------------------------------------------------------------------------

My plugin.xml

----------------------------------------------------------------------------------------------------------------------------------
<?xml version="1.0"?>
<plugin id="GetEvalSheet">
 <information>
  <name>GetEvalSheet  plugin</name>
  <description>Plugin contains a function return the sheet on which a function evaluation is taking place 
</description>
 </information>
 <loader type="Gnumeric_Builtin:module">
  <attribute value="GetEvalSheet" name="module_file"/>
 </loader>
 <services>
  <service type="function_group" id="Ninds">
   <category>Gnumeric</category>
   <category xml:lang="en">Gnumeric</category>
   <functions>
    <function name="get_EvalSheet"/>
   </functions>
  </service>
 </services>
</plugin>

--------------------------------------------------------------------------------------------------------------------------------------------------

#include <gnumeric-config.h>
#include <gnumeric.h>
#include <func.h>
#include <str.h>
#include <cell.h>
#include <sheet.h>
#include <value.h>
#include <rangefunc.h>
#include <gnm-i18n.h>
#include <gnm-plugin.h>


GNM_PLUGIN_MODULE_HEADER;

static GnmFuncHelp const help_getEvalSheet[] = {
 { GNM_FUNC_HELP_OLD,
        F_("@FUNCTION=get_EvalSheete\n"
           "@SYNTAX=get_EvalSheet()\n"
           "@DESCRIPTION= Gets the sheet from where the function is evalued"
           )
 },
 { GNM_FUNC_HELP_END }
};
static GnmValue *
get_EvalSheet (FunctionEvalInfo *ei, GnmValue const * const *argv)
{
 
 return  value_new_int (ei->pos->sheet->index_in_wb);
 
 
}

/***************************************************************************/
const GnmFuncDescriptor Ninds_functions[] = {
 { "get_EvalSheet", "", N_(""),
   help_getEvalSheet,  get_EvalSheet, NULL, NULL, NULL, NULL,
   GNM_FUNC_SIMPLE, GNM_FUNC_IMPL_STATUS_COMPLETE, GNM_FUNC_TEST_STATUS_BASIC },
   {NULL}
};

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