Table of Contents
Table of Contents
+
Table of Contents
Table of Contents
TCLAP has a few key classes to be aware of.
The first is the
-CmdLine (command line) class. This class parses
+CmdLine (command line) class. This class parses
the command line passed to it according to the arguments that it
contains. Arguments are separate objects that are added to the
-CmdLine object one at a time. The six
-argument classes are: ValueArg,
-UnlabeledValueArg,
-SwitchArg, MultiSwitchArg,
-MultiArg and
-UnlabeledMultiArg.
+CmdLine object one at a time. The six
+argument classes are: ValueArg,
+UnlabeledValueArg,
+SwitchArg, MultiSwitchArg,
+MultiArg and
+UnlabeledMultiArg.
These classes are templatized, which means they can be defined to parse
a value of any type**. Once you add the
-arguments to the CmdLine object, it parses the
+arguments to the CmdLine object, it parses the
command line
and assigns the data it finds to the specific argument objects it
contains. Your program accesses the values parsed by
-calls to the getValue() methods of the
+calls to the getValue() methods of the
argument objects.
Here is a simple example ... @@ -31,25 +31,40 @@ Here is a simple example ... #include <algorithm> #include <tclap/CmdLine.h> -using namespace TCLAP; -using namespace std; - int main(int argc, char** argv) { + using std::string; + using std::cout; + using std::cerr; + using std::endl; + // Wrap everything in a try block. Do this every time, - // because exceptions will be thrown for problems. + // because exceptions will be thrown for problems. try { - // Define the command line object. - CmdLine cmd("Command description message", ' ', "0.9"); + // Define the command line object, and insert a messages + //that tells you what the program does etc. + //The "Command description message" is printed last in the help + //text. The second argument is the delimiter (usually space) and + //the last one is the version number. The CmdLine object is used + //for parsing. + TCLAP::CmdLine cmd("Command description message", ' ', "0.9"); // Define a value argument and add it to the command line. - ValueArg<string> nameArg("n","name","Name to print",true,"homer","string"); + // A value arg takes a switch and a value such as -n Bishop + TCLAP::ValueArg<string> nameArg("n","name","Name to print",true,"homer","string"); + + // Add the argument nameArg to the command line object. This + // makes it possible to match the argument on the command line + // during parsing. cmd.add( nameArg ); // Define a switch and add it to the command line. - SwitchArg reverseSwitch("r","reverse","Print name backwards", false); - cmd.add( reverseSwitch ); + // A switch arg is a binary argument and only takes a switch + // (true/false) such as -r. Also the command line object is added + // directly while creating the SwitchArg, eliminating the need + // for the call to cmd.add(), this can be used with any type of Arg. + TCLAP::SwitchArg reverseSwitch("r","reverse","Print name backwards", false, cmd); // Parse the args. cmd.parse( argc, argv ); @@ -61,15 +76,15 @@ int main(int argc, char** argv) // Do what you intend too... if ( reverseName ) { - reverse(name.begin(),name.end()); - cout << "My name (spelled backwards) is: " << name << endl; + std::reverse(name.begin(),name.end()); + cout << "My name (spelled backwards) is: " << name << endl; } else - cout << "My name is: " << name << endl; + cout << "My name is: " << name << endl; - } catch (ArgException &e) // catch any exceptions - { cerr << "error: " << e.error() << " for arg " << e.argId() << endl; } + } catch (TCLAP::ArgException &e) // catch any exceptions + { cerr << "error: " << e.error() << " for arg " << e.argId() << endl; } }
@@ -129,85 +144,85 @@ Where: This example shows a number of different properties of the library...
help, version
+and --SwitchArgs
+are specified automatically. Using either the -h or
+--help flag will cause the USAGE message to be displayed,
+-v or --version will cause
any version information to
-be displayed, and -- or
---ignore_rest will cause the
+be displayed, and -- or
+--ignore_rest will cause the
remaining labeled arguments to be ingored. These switches are
included automatically on every command line and there is no way to
-turn this off (unless you change CmdLine.h yourself).
+turn this off (unless you change CmdLine.h yourself).
More later on how we get this to
work.-s=asdf instead of
+-s asdf, you can do so.-
+
Arguments, whatever their type, have a few common basic properties. These properties are set in the constructors of the arguments.
getopt_long()].ValueArgs
indicates whether the
-argument is required to be present (SwitchArgs
+argument is required to be present (SwitchArgs
can't be required, as that would defeat the purpose).ValueArgs is a short
description of the type
that the argument expects (yes its an ugly
hack).
Note that the order of
arguments on the command line (so far) doesn't matter. Any argument
-not matching an Arg added to the command
+not matching an Arg added to the command
line will cause an
exception to be thrown ( for the
most part, with some exceptions).
-
There are two primary types of arguments:
-
SwitchArgs are what the name implies:
+simple, on/off, boolean switches. Use SwitchArgs
anytime you want to turn
-some sort of system property on or off. SwitchArgs
-don't parse a value. They return TRUE or
-FALSE, depending on whether the switch has been found
-on the command line and what the default value was defined as.SwitchArgs
+don't parse a value. They return TRUE or
+FALSE, depending on whether the switch has been found
+on the command line and what the default value was defined as.ValueArgs are arguments that read a
value of some type
from the command line. Any time you need a file name, a number,
-etc. use a ValueArg or one of its variants.
+etc. use a ValueArg or one of its variants.
UnlabedValueArg,
MultiArg, and
UnlabeledMultiArg are
-special cases of ValueArgs and are described below. All
-ValueArgs are
+special cases of ValueArgs and are described below. All
+ValueArgs are
templatized** and will attempt to parse
the string its flag matches on the command line as the type it is
-specified as. ValueArg<int>
+specified as. ValueArg<int>
will attempt to parse an
-int, ValueArg<float> will attempt to
-parse a float, etc. If operator>>
+int, ValueArg<float> will attempt to
+parse a float, etc. If operator>>
for the specified type doesn't
recognize the string on the command line as its defined type, then
an exception will be thrown.-
TCLAP is implemented entirely in header files which means you only need to include CmdLine.h to use the library.
#include <tclap/CmdLine.h>
You'll need to make sure that your compiler can see the header -files. If you do the usual "make install" then your compiler should +files. If you do the usual "make install" then your compiler should see the files by default. Alternatively, you can use the -I complier argument to specify the exact location of the libraries.
@@ -229,37 +244,37 @@ to work on Windows, Sun and Alpha platforms. We've made every effort to keep the library compliant with the ANSI C++ standard so if your compiler meets the standard, then this library should work for you. Please let us know if this is not the case! -+
As we understand things, Visual C++ does not have the file -config.h which is used to make platform +
config.hwhich is used to make platform specific definitions. In this situation, we assume that you -have access to sstream. Our understanding is that +have access tosstream. Our understanding is that this should not be a problem for VC++ 7.x. However, if this -is not the case and you need to use strstream, +is not the case and you need to usestrstream, then simply tell your compiler to define the variable -HAVE_STRSTREAM and undefine -HAVE_SSTREAM That +HAVE_STRSTREAMand undefine +HAVE_SSTREAMThat should work. We think. Alternatively, just edit -the files ValueArg.h and MultiArg.h. +the filesValueArg.handMultiArg.h.-
-If your compiler doesn't support the using syntax used -in UnlabeledValueArg and -UnlabeledMultiArg to support two stage name lookup, +
+If your compiler doesn't support the
usingsyntax used +inUnlabeledValueArgand +UnlabeledMultiArgto support two stage name lookup, then you have two options. Either comment out the statements if you don't need two stage name lookup, or do a bunch of search and replace and use -the this pointer syntax: e.g. -this->_ignoreable instead -of just _ignorable (do this for each variable -or method referenced by using). +thethispointer syntax: e.g. +this->_ignoreableinstead +of just_ignorable(do this for each variable +or method referenced byusing).-
Table of Contents
- I want to combine multiple switches into one argument...
- I tried passing multiple values on the command line with the -same flag and it didn't work...
- I don't like labelling all of my arguments...
- I want an arbitrary number of unlabeled arguments to be accepted...
- I want one argument or the other, but not both...
- I have more arguments than single flags make sense for...
- I want to constrain the values allowed for a particular -argument...
- I want the Args to add themselves to the CmdLine...
- I want different output than what is provided...
+
Table of Contents
Naturally, what we have seen to this point doesn't satisfy all of our needs. -
-Multiple SwitchArgs can be combined into a +
+Multiple SwitchArgs can be combined into a
single argument on the command line. If you have switches -a, -b and -c
it is valid to do either:
@@ -282,11 +297,11 @@ it is valid to do either:
This is to make this library more in line with the POSIX and GNU
standards (as I understand them).
+Correct. You can neither specify mulitple ValueArgs
+or SwitchArgs with the same flag in the code nor
on the command line. Exceptions will occur in either case.
-For SwitchArgs
+For SwitchArgs
it simply doesn't make sense to allow a particular flag to be
turned on or off repeatedly on the command line. All you should
ever need is to set your state once by specifying
@@ -300,81 +315,81 @@ libraries...
% fooCompiler -L /dir/num1 -L /dir/num2 file.foo
In situations like this, you will want to use a
-MultiArg. A
-MultiArg is essentially a
-ValueArg that appends any
+MultiArg. A
+MultiArg is essentially a
+ValueArg that appends any
value that it matches and parses onto a vector of values. When the
-getValue() method is called, a vector of
+getValue() method is called, a vector of
values, instead of a single value is returned. A
-MultiArg is declared much like
-a ValueArg:
+MultiArg is declared much like
+a ValueArg:
- MultiArg<int> itest("i", "intTest", "multi int test", false,"int" );
+ MultiArg<int> itest("i", "intTest", "multi int test", false,"int" );
cmd.add( itest );
-Note that MultiArgs can be added to the
-CmdLine in any order (unlike
+Note that MultiArgs can be added to the
+CmdLine in any order (unlike
UnlabeledMultiArg).
-New Feature! MultiSwitchArg now
+New Feature! MultiSwitchArg now
allows you to set a switch multiple times on the command line. The call
-to getValue() returns the number (int) of times
+to getValue() returns the number (int) of times
the switch
has been found on the command line in addition to the default value.
Here is an example using the default initial value of 0:
- MultiSwitchArg quiet("q","quiet","Reduce the volume of output");
+ MultiSwitchArg quiet("q","quiet","Reduce the volume of output");
cmd.add( quiet );
Alternatively, you can specify your own initial value:
- MultiSwitchArg quiet("q","quiet","Reduce the volume of output",5);
+ MultiSwitchArg quiet("q","quiet","Reduce the volume of output",5);
cmd.add( quiet );
-
To this point all of our arguments have had labels (flags)
indentifying them on the command line, but there are some
situations where flags are burdensome and not worth the effort. One
example might be if you want to implement a magical command we'll
-call copy. All copy does is
+call copy. All copy does is
copy the file specified
in the first argument to the file specified in the second argument.
-We can do this using UnlabeledValueArgs which are pretty
-much just ValueArgs without the flag specified,
+We can do this using UnlabeledValueArgs which are pretty
+much just ValueArgs without the flag specified,
which tells
-the CmdLine object to treat them accordingly.
+the CmdLine object to treat them accordingly.
The code would look like this:
- UnlabeledValueArg<float> nolabel( "name", "unlabeled test", 3.14,
- "nameString" );
+ UnlabeledValueArg<float> nolabel( "name", "unlabeled test", 3.14,
+ "nameString" );
cmd.add( nolabel );
Everything else is handled identically to what is seen above. The
only difference to be aware of, and this is important: the order
-that UnlabeledValueArgs are added to the CmdLine
+that UnlabeledValueArgs are added to the CmdLine
is the order that they will be parsed!!!!
This is not the case for normal
-SwitchArgs and ValueArgs.
+SwitchArgs and ValueArgs.
What happens internally is the first argument that the
-CmdLine doesn't recognize is assumed to be
-the first UnlabeledValueArg and
+CmdLine doesn't recognize is assumed to be
+the first UnlabeledValueArg and
parses it as such. Note that you are allowed to intersperse labeled
args (SwitchArgs and ValueArgs) in between
-UnlabeledValueArgs (either on the command line
-or in the declaration), but the UnlabeledValueArgs
+UnlabeledValueArgs (either on the command line
+or in the declaration), but the UnlabeledValueArgs
will still be parsed in the order they are added. Just remember that order is
important for unlabeled arguments.
-
Don't worry, we've got you covered. Say you want a strange command that searches each file specified for a given string (let's call it -grep), but you don't want to have to type in all of the file +grep), but you don't want to have to type in all of the file names or write a script to do it for you. Say,
@@ -382,7 +397,7 @@ names or write a script to do it for you. Say,
First remember that the * is handled by the shell and -expanded accordingly, so what the program grep sees is +expanded accordingly, so what the program grep sees is really something like:
@@ -390,13 +405,13 @@ really something like:
To handle situations where multiple, unlabled arguments are needed,
-we provide the UnlabeledMultiArg.
-UnlabeledMultiArgs
+we provide the UnlabeledMultiArg.
+UnlabeledMultiArgs
are declared much like everything else, but with only a description
-of the arguments. By default, if an UnlabeledMultiArg
+of the arguments. By default, if an UnlabeledMultiArg
is specified, then at least one is required to be present or an
exception will be thrown. The most important thing to remember is,
-that like UnlabeledValueArgs: order matters!
+that like UnlabeledValueArgs: order matters!
In fact, an UnlabeledMultiArg must be the last argument added to the
CmdLine!. Here is what a declaration looks like:
@@ -405,7 +420,7 @@ CmdLine!. Here is what a declaration looks like:
//
// UnlabeledMultiArg must be the LAST argument added!
//
- UnlabeledMultiArg<string> multi("file names");
+ UnlabeledMultiArg<string> multi("file names");
cmd.add( multi );
cmd.parse(argc, argv);
@@ -413,69 +428,69 @@ CmdLine!. Here is what a declaration looks like:
-You must only ever specify one (1) UnlabeledMultiArg.
-One UnlabeledMultiArg will read every unlabeled
+You must only ever specify one (1) UnlabeledMultiArg.
+One UnlabeledMultiArg will read every unlabeled
Arg that wasn't already processed by a
-UnlabeledValueArg into a
-vector of type T. Any
-UnlabeledValueArg or other
-UnlabeledMultiArg specified after the first
-UnlabeledMultiArg will be ignored, and if
+UnlabeledValueArg into a
+vector of type T. Any
+UnlabeledValueArg or other
+UnlabeledMultiArg specified after the first
+UnlabeledMultiArg will be ignored, and if
they are required,
exceptions will be thrown. When you call the
-getValue()
-method of the UnlabeledValueArg argument,
-a vector
+getValue()
+method of the UnlabeledValueArg argument,
+a vector
will be returned. If you can imagine a situation where there will
be multiple args of multiple types (stings, ints, floats, etc.)
-then just declare the UnlabeledMultiArg as type
-string and parse the different values yourself or use
-several UnlabeledValueArgs.
-
+then just declare the UnlabeledMultiArg as type
+string and parse the different values yourself or use
+several UnlabeledValueArgs.
+
Suppose you have a command that must read input from one of two
possible locations, either a local file or a URL. The command
must read something, so one
argument is required, but
not both, yet neither argument is strictly necessary by itself.
-This is called "exclusive or" or "XOR". To accomodate this
+This is called "exclusive or" or "XOR". To accomodate this
situation, there is now an option to add two or more
-Args to
-a CmdLine that are exclusively or'd with one another:
-xorAdd(). This means that exactly one of the
-Args must be set and no more.
+Args to
+a CmdLine that are exclusively or'd with one another:
+xorAdd(). This means that exactly one of the
+Args must be set and no more.
-xorAdd() comes in two flavors, either
-xorAdd(Arg& a, Arg& b)
-to add just two Args to be xor'd and
-xorAdd( vector<Arg*> xorList )
-to add more than two Args.
+xorAdd() comes in two flavors, either
+xorAdd(Arg& a, Arg& b)
+to add just two Args to be xor'd and
+xorAdd( vector<Arg*> xorList )
+to add more than two Args.
- ValueArg<string> fileArg("f","file","File name to read",true,"homer",
- "filename");
- ValueArg<string> urlArg("u","url","URL to load",true,
- "http://example.com", "URL");
+ ValueArg<string> fileArg("f","file","File name to read",true,"homer",
+ "filename");
+ ValueArg<string> urlArg("u","url","URL to load",true,
+ "http://example.com", "URL");
cmd.xorAdd( fileArg, urlArg );
cmd.parse(argc, argv);
-Once one Arg in the xor list is matched on the
-CmdLine then the others in the xor list will be
+Once one Arg in the xor list is matched on the
+CmdLine then the others in the xor list will be
marked as set. The question then, is how to determine which of the
-Args has been set? This is accomplished by calling the
-isSet() method for each Arg. If the
-Arg has been
-matched on the command line, the isSet() will return
-TRUE, whereas if the Arg
-has been set as a result of matching the other Arg
-that was xor'd isSet() will
-return FALSE.
-(Of course, if the Arg was not xor'd and
-wasn't matched, it will also return FALSE.)
+Args has been set? This is accomplished by calling the
+isSet() method for each Arg. If the
+Arg has been
+matched on the command line, the isSet() will return
+TRUE, whereas if the Arg
+has been set as a result of matching the other Arg
+that was xor'd isSet() will
+return FALSE.
+(Of course, if the Arg was not xor'd and
+wasn't matched, it will also return FALSE.)
@@ -486,101 +501,101 @@ wasn't matched, it will also return FALSE.)
else
// Should never get here because TCLAP will note that one of the
// required args above has not been set.
- throw("Very bad things...");
+ throw("Very bad things...");
-
Some commands have so many options that single flags no longer map
sensibly to the available options. In this case, it is desirable to
-specify Args using only long options. This one is easy to
-accomplish, just make the flag value blank in the Arg
-constructor. This will tell the Arg that only the long
+specify Args using only long options. This one is easy to
+accomplish, just make the flag value blank in the Arg
+constructor. This will tell the Arg that only the long
option should be matched and will force users to specify the long
option on the command line. The help output is updated accordingly.
- ValueArg<string> fileArg("","file","File name",true,"homer","filename");
+ ValueArg<string> fileArg("","file","File name",true,"homer","filename");
- SwitchArg caseSwitch("","upperCase","Print in upper case",false);
+ SwitchArg caseSwitch("","upperCase","Print in upper case",false);
Interface Change!!! Sorry folks, but we've changed
-the interface to constraining Args. Constraints are
-now hidden behind the Constraint interface. To
-constrain an Arg simply implement the interface
+the interface to constraining Args. Constraints are
+now hidden behind the Constraint interface. To
+constrain an Arg simply implement the interface
and specify the new class in the constructor as before.
-Fear not, you can still constrain Args based on
-a list of values. Instead of adding a vector of
-allowed values to the Arg directly,
-create a ValuesConstraint object
-with a vector of values and add that to the
-Arg. The Arg constructors
+Fear not, you can still constrain Args based on
+a list of values. Instead of adding a vector of
+allowed values to the Arg directly,
+create a ValuesConstraint object
+with a vector of values and add that to the
+Arg. The Arg constructors
have been modified accordingly.
When the value for the
-Arg is parsed,
+Arg is parsed,
it is checked against the list of values specified in the
-ValuesConstraint.
+ValuesConstraint.
If the value is in the list then it is accepted. If
not, then an exception is thrown. Here is a simple example:
vector<string> allowed;
- allowed.push_back("homer");
- allowed.push_back("marge");
- allowed.push_back("bart");
- allowed.push_back("lisa");
- allowed.push_back("maggie");
+ allowed.push_back("homer");
+ allowed.push_back("marge");
+ allowed.push_back("bart");
+ allowed.push_back("lisa");
+ allowed.push_back("maggie");
ValuesConstraint<string> allowedVals( allowed );
- ValueArg<string> nameArg("n","name","Name to print",true,"homer",&allowedVals);
+ ValueArg<string> nameArg("n","name","Name to print",true,"homer",&allowedVals);
cmd.add( nameArg );
-When a ValuesConstraint is specified,
+When a ValuesConstraint is specified,
instead of a type description being specified in the
-Arg, a
+Arg, a
type description is created by concatenating the values in the
allowed list using operator<< for the specified type. The
-help/usage for the Arg therefore lists the
+help/usage for the Arg therefore lists the
allowable values. Because of this, you might want to keep the list
relatively small, however there is no limit on this.
Obviously, a list of allowed values isn't always the best way to
constrain things. For instance, one might wish to allow only
integers greater than 0. In this case, simply create a class that
-implements the Constraint<int> interface and
+implements the Constraint<int> interface and
checks whether the value parsed is greater than 0 (done in the
-check() method) and create your
-Arg with your new Constraint.
-
-New constructors have beed added for each Arg
-that take a CmdLine object as an argument.
-Each Arg then
-adds itself to the CmdLine
-object. There is no difference in how the Arg
+check() method) and create your
+Arg with your new Constraint.
+
+New constructors have beed added for each Arg
+that take a CmdLine object as an argument.
+Each Arg then
+adds itself to the CmdLine
+object. There is no difference in how the Arg
is handled between this method and calling the
-add() method directly. At the moment, there is
-no way to do an xorAdd() from the constructor. Here
+add() method directly. At the moment, there is
+no way to do an xorAdd() from the constructor. Here
is an example:
// Create the command line.
- CmdLine cmd("this is a message", '=', "0.99" );
+ CmdLine cmd("this is a message", '=', "0.99" );
- // Note that the following args take the "cmd" object as arguments.
- SwitchArg btest("B","existTestB", "exist Test B", false, cmd );
+ // Note that the following args take the "cmd" object as arguments.
+ SwitchArg btest("B","existTestB", "exist Test B", false, cmd );
- ValueArg<string> stest("s", "stringTest", "string test", true, "homer",
- "string", cmd );
+ ValueArg<string> stest("s", "stringTest", "string test", true, "homer",
+ "string", cmd );
- UnlabeledValueArg<string> utest("unTest1","unlabeled test one",
- "default","string", cmd );
+ UnlabeledValueArg<string> utest("unTest1","unlabeled test one",
+ "default","string", cmd );
// NO add() calls!
@@ -588,14 +603,14 @@ is an example:
cmd.parse(argc,argv);
-
It is straightforward to change the output generated by
TCLAP. Either subclass the
-StdOutput class and re-implement the methods you choose,
+StdOutput class and re-implement the methods you choose,
or write your own class that implements the
-CmdLineOutput interface. Once you have done this,
-then use the CmdLine setOutput
-method to tell the CmdLine to use your new output
+CmdLineOutput interface. Once you have done this,
+then use the CmdLine setOutput
+method to tell the CmdLine to use your new output
class. Here is a simple example:
class MyOutput : public StdOutput
@@ -603,28 +618,28 @@ class MyOutput : public StdOutput
public:
virtual void failure(CmdLineInterface& c, ArgException& e)
{
- cerr << "My special failure message for: " << endl
+ cerr << "My special failure message for: " << endl
<< e.what() << endl;
}
virtual void usage(CmdLineInterface& c)
{
- cout << "my usage message:" << endl;
+ cout << "my usage message:" << endl;
list<Arg*> args = c.getArgList();
for (ArgListIterator it = args.begin(); it != args.end(); it++)
cout << (*it)->longID()
- << " (" << (*it)->getDescription() << ")" << endl;
+ << " (" << (*it)->getDescription() << ")" << endl;
}
virtual void version(CmdLineInterface& c)
{
- cout << "my version message: 0.1" << endl;
+ cout << "my version message: 0.1" << endl;
}
};
int main(int argc, char** argv)
{
- CmdLine cmd("this is a message", ' ', "0.99" );
+ CmdLine cmd("this is a message", ' ', "0.99" );
// set the output
MyOutput my;
@@ -633,81 +648,81 @@ int main(int argc, char** argv)
// proceed normally ...
-See test4.cpp in the examples directory for the full
+See test4.cpp in the examples directory for the full
example. NOTE: if you supply your own Output object, we
-will not delete it in the CmdLine destructor. This
+will not delete it in the CmdLine destructor. This
could lead to a (very small) memory leak if you don't take care of the object
yourself.
-
Table of Contents
+
Table of Contents
Like all good rules, there are many exceptions.... -
-The -- flag is automatically included in the -CmdLine. +
+The -- flag is automatically included in the
+CmdLine.
As (almost) per POSIX and GNU standards, any argument specified
-after the -- flag is ignored.
+after the -- flag is ignored.
Almost because if an
-UnlabeledValueArg that has not been set or an
-UnlabeledMultiArg has been specified, by default
-we will assign any arguments beyond the --
+UnlabeledValueArg that has not been set or an
+UnlabeledMultiArg has been specified, by default
+we will assign any arguments beyond the --
to the those arguments as
per the rules above. This is primarily useful if you want to pass
in arguments with a dash as the first character of the argument. It
-should be noted that even if the -- flag is
-passed on the command line, the CmdLine will
+should be noted that even if the -- flag is
+passed on the command line, the CmdLine will
still test to make sure all of the required
arguments are present.
Of course, this isn't how POSIX/GNU handle things, they explicitly
-ignore arguments after the --. To accomodate this,
-we can make both UnlabeledValueArgs and
-UnlabeledMultiArgs ignoreable in their constructors.
+ignore arguments after the --. To accomodate this,
+we can make both UnlabeledValueArgs and
+UnlabeledMultiArgs ignoreable in their constructors.
See the API Documentation for details.
-
+No longer a problem! Just use MultiSwitchArg.
There is a description here.
-
Disclaimer: Almost no one will have any use for
-Visitors, they were
+Visitors, they were
added to provide special handling for default arguments. Nothing
-that Visitors do couldn't be accomplished
+that Visitors do couldn't be accomplished
by the user after the
command line has been parsed. If you're still interested, keep
reading...
-Some of you may be wondering how we get the --help,
---version and --
+Some of you may be wondering how we get the --help,
+--version and --
arguments to do their thing without mucking up the
-CmdLine code with lots of if
+CmdLine code with lots of if
statements and type checking. This is accomplished by using a
variation on the Visitor Pattern. Actually, it may not be a Visitor
Pattern at all, but that's what inspired me.
If we want some argument to do some sort of special handling,
-besides simply parsing a value, then we add a Visitor
-pointer to the Arg. More specifically, we add a
-subclass of the Visitor
+besides simply parsing a value, then we add a Visitor
+pointer to the Arg. More specifically, we add a
+subclass of the Visitor
class. Once the argument has been successfully parsed, the
-Visitor for that argument is
+Visitor for that argument is
called. Any data that needs to be operated on is declared in the
-Visitor constructor and then operated on in the
-visit() method. A Visitor
-is added to an Arg as the last argument in its
+Visitor constructor and then operated on in the
+visit() method. A Visitor
+is added to an Arg as the last argument in its
declaration. This may sound
complicated, but it is pretty straightforward. Let's see an
example.
-Say you want to add an --authors flag to a program that
+Say you want to add an --authors flag to a program that
prints the names of the authors when present. First subclass
-Visitor:
+Visitor:
-#include "Visitor.h"
+#include "Visitor.h"
#include <string>
#include <iostream>
@@ -717,29 +732,29 @@ class AuthorVisitor : public Visitor
string _author;
public:
AuthorVisitor(const string& name ) : Visitor(), _author(name) {} ;
- void visit() { cout << "AUTHOR: " << _author << endl; exit(0); };
+ void visit() { cout << "AUTHOR: " << _author << endl; exit(0); };
};
Now include this class definition somewhere and go about creating
your command line. When you create the author switch, add the
-AuthorVisitor pointer as follows:
+AuthorVisitor pointer as follows:
- SwitchArg author("a","author","Prints author name", false,
- new AuthorVisitor("Homer J. Simpson") );
+ SwitchArg author("a","author","Prints author name", false,
+ new AuthorVisitor("Homer J. Simpson") );
cmd.add( author );
-Now, any time the -a or
---author flag is specified,
+Now, any time the -a or
+--author flag is specified,
the program will print the author name, Homer J. Simpson and exit
without processing any further (as specified in the
-visit() method).
-
For more information, look at the
API Documentation and the examples included with the
distribution.
diff --git a/docs/manual.xml b/docs/manual.xml
index aa75498..d13071b 100644
--- a/docs/manual.xml
+++ b/docs/manual.xml
@@ -68,25 +68,40 @@ Here is a simple