129 lines
3.9 KiB
ReStructuredText
129 lines
3.9 KiB
ReStructuredText
==================================
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Calculation
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==================================
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Calculation is a generic object that allow you to call an external function.
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Simple calculation
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==================================
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It's structure is the following :
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.. literalinclude:: src/calculation.py
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:lines: 1-5
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:linenos:
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Positional and keyword arguments
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=========================================
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Function's arguments are also specified in this object.
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Let's see with a positional argument and a keyword argument:
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.. literalinclude:: src/calculation.py
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:lines: 8-10
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:linenos:
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The function `a_function_with_parameters` will be call with the positional argument `value1` to `my value 1` and the keyword argument `value2` to `my value 2`.
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So when this function will be executed, it will return `my value 1 my value 2`.
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Let's see with two positional arguments:
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.. literalinclude:: src/calculation.py
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:lines: 13-15
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:linenos:
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As we have several positional arguments, the first Params' argument is a tuple.
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This example will return strictly same result has previous example.
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Option has an argument
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=========================================
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In previous examples, we use ParamValue arguments, which could contain random value. But this value is static and cannot be change.
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It could be interesting to use an existant option has an argument:
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.. literalinclude:: src/calculation.py
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:lines: 18-21
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:linenos:
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As long as option1 is at its default value, the function will return `1`. If we set option1 to `12`, the function will return `12`.
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Pay attention to the properties when you use an option.
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This example will raise a ConfigError:
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.. literalinclude:: src/calculation.py
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:lines: 24-27
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:linenos:
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It's up to you to define the desired behavior.
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If you want the option to be transitively disabled just set the raisepropertyerror argument to True:
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.. literalinclude:: src/calculation.py
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:lines: 29-31
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:linenos:
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If you want to remove option in argument, just set the notraisepropertyerror argument to True:
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.. literalinclude:: src/calculation.py
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:lines: 33-35
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:linenos:
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In this case, option1 will not pass to function. You have to set a default value to this argument.
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So, function will return `None`.
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In these examples, the function only accesses to the value of the option. But no additional information is given.
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It is possible to add the parameter `todict` to `True` to have the description of the option in addition to its value.
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.. literalinclude:: src/calculation.py
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:lines: 37-39
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:linenos:
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This function will return `the option first option has value 1`.
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Multi option has an argument
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=========================================
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An option could be a multi. Here is an example:
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.. literalinclude:: src/calculation.py
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:lines: 46-49
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:linenos:
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In this case the function will return the complete list. So `[1]` in this example.
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Leader or follower option has an argument
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============================================
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An option could be a leader:
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.. literalinclude:: src/calculation.py
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:lines: 51-57
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:linenos:
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If the calculation is used in a standard multi, it will return `[1]`.
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If the calculation is used in a follower, it will return `1`.
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An option could be a follower:
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.. literalinclude:: src/calculation.py
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:lines: 59-65
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:linenos:
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If the calculation is used in a standard multi, it will return `[2]`.
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If the calculation is used in a follower, it will return `2`.
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If the calculation is used in a follower we can also retrieve the actual follower index:
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.. literalinclude:: src/calculation.py
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:lines: 67-73
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:linenos:
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Context has an argument
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=========================================
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It is possible to recover a copy of the context directly in a function. On the other hand, the use of the context in a function is a slow action which will haunt the performances. Use it only in case of necessity:
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.. literalinclude:: src/calculation.py
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:lines: 42-44
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:linenos:
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