[Gambas-user] SimpleEval

[Fabien Bodard]

In fact internally it use two process.

the first one when you set the formula. It compile it... understand
reorganize and traduce the formula into interpreter readable
sequences.
The second one when you call Execute, the interpreter read the stored sequence.
During this process if some variables are used the interpreter raise
the data event and give the required var name. So you can give it
throuth the .data property.


Internally the interpreter have bridges to every math and string
common functions of Gambas. You can extent the functions by inheriting
the simpleEval and adding your own function.

example :

Export
Inherits SimpleEval

Public Sub _New()

  SimpleEval.Functions.Add("Message")
  SimpleEval.FunctionsArgsCount.Add(1)

End


''Show a windowed message
Public Sub _MESSAGE(Val1 As CResult) As CResult

  Message(Val1.Value)
  Return New CResult(Null, CResult.TypeValue)

End

Void not exist, you must return a null result on a void function.


Simple eval does what i need... a simple extendable formula
interpreter like the one we can se on spreadsheet. I use it now on
report too.
So i can say now "='Page ' & page & ' on ' & pages"

I forgot " and ' are accepted for string delemiter


2015-12-30 7:21 GMT+01:00 Fabien Bodard <gambas.fr at ...626...>:
> you can get the error and the error pos too,
>
> i've updated the class on the farm to remove the compilation warnings
>
> 2015-12-30 7:21 GMT+01:00 Fabien Bodard <gambas.fr at ...626...>:
>> From the Main Module in the Farm example :
>>
>>
>> Public Sub Main()
>>   Dim hEval As New SimpleEval As "Eval"
>>   Dim hEx As New EvalEx As "Eval"
>>
>>   'Test with an unknown variable
>>   hEval.Formula = "IF(Test=1;'TROUVE';'PERDU')"
>>   hEval.Execute
>>   If Not hEval.Error Then
>>     Print hEval.Value
>>   Else
>>     Print hEval.ErrorText
>>   Endif
>>
>>
>>   'Test extention
>>   hEx.Formula = "Message('coucou')"
>>   hEx.Execute
>>
>>   'Test Both
>>    hEx.Formula = "Message(If(Test=1;'TROUVE ' & prenom;'PERDU'))"
>>   hEx.Execute
>>
>>   'Test Calculation
>>   hEx.Formula = "Cos(1)+pi()*2^mypower"
>>   hEx.Execute
>>   Print hEx.Value
>>
>> End
>>
>>
>> Public Sub Eval_Data(Value As String)
>>
>>   If Value = "Test" Then
>>     Last.data = 1
>>   Endif
>>   If Value = "mypower" Then
>>     Last.data = 3
>>   Endif
>>   If Value = "prenom" Then Last.Data = "Fabien"
>>
>>
>> End
>>
>> 2015-12-30 7:10 GMT+01:00 Fabien Bodard <gambas.fr at ...626...>:
>>> You get the class from where ?
>>>
>>>
>>> 2015-12-29 15:18 GMT+01:00 Charlie <charlie at ...2793...>:
>>>> Hi Fabian,
>>>> I presume that you wrote the code in SimpleEval. I can't work out how to use
>>>> it. I thought it might work with my gbCalculator (see Gmabas Farm). There
>>>> are quite a few compile warning errors.
>>>> <http://gambas.8142.n7.nabble.com/file/n55114/CompileErrors.png>
>>>> *The main thing is some examples on how to use it please.*
>>>> Thanks.
>>>>
>>>>
>>>>
>>>> --
>>>> View this message in context: http://gambas.8142.n7.nabble.com/SimpleEval-tp55114.html
>>>> Sent from the gambas-user mailing list archive at Nabble.com.
>>>> ------------------------------------------------------------------------------
>>>> _______________________________________________
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>>>
>>>
>>>
>>> --
>>> Fabien Bodard
>>
>>
>>
>> --
>> Fabien Bodard
>
>
>
> --
> Fabien Bodard



-- 
Fabien Bodard