How to simply print both variables' names & values in MQL4? - algorithmic-trading

Question

I hope to write a function PrintVars() that is able to print the variables altogether with their names. e.g.:
int var1 = 1;
bool var2 = True;
int var3 = 2;
PrintVars( var1, var2, var3 );
The expected output to the console is:
var1=1
var2=true
var3=2
The difficulty here is to
Get the variable name;
passing parameters of various types to the function.
Is there a way to achieve 1 and 2?

Answer 1

Neither 1) nor 2)
as MQL4 is a strong typed, compiled language.
Other possibilities to escape from this language syntax constraint ?
One may design a middle-ware tool for doing this, either locally, inside MQL4 or externally, via a messaging based distributed system ( having a remote terminal window ).
MQL4-based polymorphism is somewhat easier with class-based calling interface, while the efforts would be immense if such module ought be elaborated for some production grade deployment.
Somewhat clumsy sketch of the approach follows:
- create your vars as a properly configured polymorphic instance of aNamedVARIABLE class
- create a printing function, receiving a long list ( or a placeholder ( string &NameValueARRAY[] ) for a string array[][2]; initialised with "" and pre-filled with Name-Value pairs by .getName2PRINT(), resp. .getValue2PRINT() public methods ) of string variables to print, unless they are left as just initialised == ""
string printFun( const string N1 = "",
const string V1 = "",
const string N2 = "",
const string V2 = "",
...
..
.
){ string aPrintSTRING = "";
aPrintSTRING += ( ( N1 != "" ) ? ( N1 + " = " + V1 ) : "" );
aPrintSTRING += ( ( N2 != "" ) ? ( N2 + " = " + V2 ) : "" );
aPrintSTRING += ( ( N3 != "" ) ? ( N3 + " = " + V3 ) : "" );
...
..
.
return( aPrintSTRING );
}
...
..
.
print( printFun( aNamedVAR1.getName2PRINT(), aNamedVAR1.getValue2PRINT(),
aNamedVAR2.getName2PRINT(), aNamedVAR2.getValue2PRINT(),
aNamedVAR3.getName2PRINT(), aNamedVAR3.getValue2PRINT(),
aNamedVAR4.getName2PRINT(), aNamedVAR4.getValue2PRINT()
)
);
class aNamedVARIABLE{
private:
string aNameAsSTRING = "";
bool aValueAsBOOL = False;
bool aValueAsBOOL_[] = {};
int aValueAsINT = EMPTY_VALUE;
int aValueAsINT_[] = {};
string aValueAsSTR = "";
string aValueAsSTR_[] = {};
...
..
.
isBoolean = False;
isInteger = False;
isShort = False;
isUint = False;
isUchar = False;
isChar = False;
isString = False;
isDouble = False;
isDatetime = False;
isColor = False;
isClass = False;
isEnum = False;
isStruct = False;
isBooleanArr = False;
isIntegerArr = False;
isUintArr = False;
isShortArr = False;
isUintArr = False;
isUcharArr = False;
isDoubleArr = False;
isDatetimeArr = False;
isColorArr = False;
public:
aNamedVARIABLE() {}; // default constructor
aNamedVARIABLE( const string aName,
const bool aBool ){ aNamedVARIABLE::setBool( aBool );
aNamedVARIABLE::setName( aName );
}
aNamedVARIABLE( const string aName,
const int anInt ){ aNamedVARIABLE::setInt( anInt );
aNamedVARIABLE::setName( aName );
}
...
..
.
getName2PRINT() { return( this.aNameAsSTRING );
}
getValue2PRINT() { if ( this.isBoolean ) return( this.aValueAsBOOL ? "True" : "False" );
if ( this.isInteger ) return( str( this.aValueAsINT ) );
...
..
.
}
}