StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POC++ runtime datatype identification & avoiding switch-case
text
Body
copied!<p>I have the following code that I hope to simplify and minimize duplication.</p> <pre><code>// Gather.cpp void GetParam() { ProParameter * param; // 3rd party struct ProParamvalue proValue; // 3rd party struct ProParameterValueGet( param, & proValue ); // this is a call to a 3rd Party API shared_ptr< CPartParam > pParam; // CPartParam is my class /* The .type in switch() statement is an enum with following definition: typedef enum param_value_types { PRO_PARAM_DOUBLE = 50, /* use d_val from ProParamvalueValue to set value * PRO_PARAM_STRING = 51, /* use s_val from ProParamvalueValue to set value * } ProParamvalueType; */ // WUD LOVE TO ELIMINATE THE SWITCH-CASE switch( proValue.type ) // .type is enum as above { case PRO_PARAM_DOUBLE: // 3rd party enum value pParam->SetValue( proValue.value.d_val ); break; case PRO_PARAM_STRING: // 3rd party enum value pParam->SetValue( proValue.value.s_val ); break; default: break; } } // PartData.h class CPartParam { public: enum ValueType { DOUBLE, STRING }; ValueType m_eValueType; double m_dVal; wstring m_sVal; bool SetValue( const double & dVal ); bool SetValue( const wstring & sVal ); }; // PartData.cpp // There is one overload for each data-type. WUD LOVE TO CONDENSE TO A SINGLE METHOD/TEMPLATE FUNCTION THAT CAN SET THE VALUE IRRESPECTIVE OF THE DATA-TYPE. void CPartParam::SetValue( const double & dVal ) { m_eValueType = DOUBLE; m_dVal = dVal; } bool CPartParam::SetValue( const wstring & sVal ) { m_eValueType = STRING; m_sVal = sVal; } </code></pre> <p>As can be seen the datatype of the "proValue.type" is determined at runtime, which forces me to write repetitive code: CPartParam::SetValue() overloads (one for each data-type). I would LOVE it if I can avoid the switch-case loop in GetParam(), if at all possible.</p> <p>There is more repetitive code with a 2nd switch-case when the data stored in CPartParam shared_ptr has to retrieved (i.e. CPartParam::GetValue).</p> <p>I have shown sample code (may not necessarily compile), but will fix if anyone wants to compile.</p> <p>I have shown only two data-types (PRO_PARAM_DOUBLE, PRO_PARAM_STRING) but there are a handful more.</p> <p>The only restrictions I have are that our dev team still uses Boost 1.36.0, Visual Studio 2005 (primary reason is due to the 3rd party library). We need to use boost::serialization, so recommendations to use any new data-types has the restriction that that new data-type must be serializable using boost::serialization in boost version 1.36.0.</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload