Template Class ValueArg

• Defined in File value_arg.hpp

Inheritance Relationships

Base Type

• public ecl::Arg (Class Arg)

Derived Type

• public ecl::UnlabeledValueArg< T > (Template Class UnlabeledValueArg)

Class Documentation

template<class T>
class ValueArg : public ecl::Arg

The basic labeled argument that parses a value. This is a template class, which means the type T defines the type that a given object will attempt to parse when the flag/name is matched on the command line. While there is nothing stopping you from creating an unflagged ValueArg, it is unwise and would cause significant problems. Instead use an UnlabeledValueArg.

Subclassed by ecl::UnlabeledValueArg< T >

Public Functions

ValueArg(const std::string &flag, const std::string &name, const std::string &desc, bool req, T value, const std::string &typeDesc, Visitor *v = NULL)

Labeled ValueArg

constructor. You could conceivably call this constructor with a blank flag, but that would make you a bad person. It would also cause an exception to be thrown. If you want an unlabeled argument, use the other constructor.

Constructor implementation.

Parameters:

• flag – - The one character flag that identifies this argument on the command line.

• name – - A one word name for the argument. Can be used as a long flag on the command line.

• desc – - A description of what the argument is for or does.

• req – - Whether the argument is required on the command line.

• value – - The default value assigned to this argument if it is not present on the command line.

• typeDesc – - A short, human readable description of the type that this object expects. This is used in the generation of the USAGE statement. The goal is to be helpful to the end user of the program.

• v – - An optional visitor. You probably should not use this unless you have a very good reason.

ValueArg(const std::string &flag, const std::string &name, const std::string &desc, bool req, T value, const std::string &typeDesc, CmdLineInterface &parser, Visitor *v = NULL)

Labeled ValueArg constructor. You could conceivably call this constructor with a blank flag, but that would make you a bad person. It would also cause an exception to be thrown. If you want an unlabeled argument, use the other constructor.

Parameters:

• flag – - The one character flag that identifies this argument on the command line.

• name – - A one word name for the argument. Can be used as a long flag on the command line.

• desc – - A description of what the argument is for or does.

• req – - Whether the argument is required on the command line.

• value – - The default value assigned to this argument if it is not present on the command line.

• typeDesc – - A short, human readable description of the type that this object expects. This is used in the generation of the USAGE statement. The goal is to be helpful to the end user of the program.

• parser – - A CmdLine parser object to add this Arg to

• v – - An optional visitor. You probably should not use this unless you have a very good reason.

ValueArg(const std::string &flag, const std::string &name, const std::string &desc, bool req, T value, Constraint<T> *constraint, CmdLineInterface &parser, Visitor *v = NULL)

Labeled ValueArg constructor. You could conceivably call this constructor with a blank flag, but that would make you a bad person. It would also cause an exception to be thrown. If you want an unlabeled argument, use the other constructor.

Parameters:

• flag – - The one character flag that identifies this argument on the command line.

• name – - A one word name for the argument. Can be used as a long flag on the command line.

• desc – - A description of what the argument is for or does.

• req – - Whether the argument is required on the command line.

• value – - The default value assigned to this argument if it is not present on the command line.

• constraint – - A pointer to a Constraint object used to constrain this Arg.

• parser – - A CmdLine parser object to add this Arg to.

• v – - An optional visitor. You probably should not use this unless you have a very good reason.

ValueArg(const std::string &flag, const std::string &name, const std::string &desc, bool req, T value, Constraint<T> *constraint, Visitor *v = NULL)

Labeled ValueArg constructor. You could conceivably call this constructor with a blank flag, but that would make you a bad person. It would also cause an exception to be thrown. If you want an unlabeled argument, use the other constructor.

Parameters:

• flag – - The one character flag that identifies this argument on the command line.

• name – - A one word name for the argument. Can be used as a long flag on the command line.

• desc – - A description of what the argument is for or does.

• req – - Whether the argument is required on the command line.

• value – - The default value assigned to this argument if it is not present on the command line.

• constraint – - A pointer to a Constraint object used to constrain this Arg.

• v – - An optional visitor. You probably should not use this unless you have a very good reason.

virtual bool processArg(int *i, std::vector<std::string> &args)

Handles the processing of the argument. This re-implements the Arg

version of this method to set the _value of the argument appropriately. It knows the difference between labeled and unlabeled.

Implementation of

processArg().

Parameters:

• i – - Pointer the the current argument in the list.

• args – - Mutable list of strings. Passed in from main().

T &getValue()

Returns the value of the argument.

Implementation of getValue().

virtual std::string shortID(const std::string &val = "val") const

Specialization of shortID.

Implementation of shortID.

Parameters:

val – - value to be used.

virtual std::string longID(const std::string &val = "val") const

Specialization of longID.

Implementation of longID.

Parameters:

val – - value to be used.

Protected Functions

void _extractValue(const std::string &val)

Extracts the value from the string. Attempts to parse string as type T, if this fails an exception is thrown.

Parameters:

val – - value to be parsed.

Protected Attributes

T _value

The value parsed from the command line. Can be of any type, as long as the >> operator for the type is defined.

std::string _typeDesc

A human readable description of the type to be parsed. This is a hack, plain and simple. Ideally we would use RTTI to return the name of type T, but until there is some sort of consistent support for human readable names, we are left to our own devices.

Constraint<T> *_constraint

A Constraint this Arg must conform to.