Feature Request #8 Implicit Conversion Operators for SwitchArg and ValueArg.

examples/Makefile.am

@@ -2,7 +2,7 @@
 noinst_PROGRAMS = test1 test2 test3 test4 test5 test6 test7 test8 test9 \
 			test10 test11 test12 test13 test14 test15 test16 \
 			test17 test18 test19 test20 test21 test22 test23 test24 \
-			test25 test26
+			test25 test26 test27
 
 test1_SOURCES = test1.cpp
 test2_SOURCES = test2.cpp
@@ -30,6 +30,7 @@ test23_SOURCES = test23.cpp
 test24_SOURCES = test24.cpp
 test25_SOURCES = test25.cpp
 test26_SOURCES = test26.cpp
+test27_SOURCES = test27.cpp
 
 AM_CPPFLAGS = -I$(top_srcdir)/include
 

examples/test27.cpp

@@ -0,0 +1,26 @@
+#include "tclap/CmdLine.h"
+#include <iostream>
+#include <string>
+
+using namespace TCLAP;
+using namespace std;
+
+int main(int argc, char** argv)
+{
+
+    CmdLine cmd("test arg conversion operator");
+    SwitchArg falseSwitch("f","false", "test false condition", cmd, false);
+    SwitchArg trueSwitch("t","true", "tests true condition", cmd, true);
+    ValueArg<string> strArg("s","str", "test string arg", false, "defStr", "string", cmd);
+    ValueArg<int> intArg("i","int", "tests int arg", false, 4711, "integer", cmd);
+
+    cmd.parse(argc, argv);
+
+    string s = strArg;
+    int i = intArg;
+
+    cout << "for falseSwitch we got : " << falseSwitch << endl
+	 << "for trueSwitch we got : " << trueSwitch << endl
+	 << "for strArg we got : " << s << endl
+	 << "for intArg we got : " << i << endl;
+}

include/tclap/SwitchArg.h

@@ -112,7 +112,14 @@ class SwitchArg : public Arg
 		/**
 		 * Returns bool, whether or not the switch has been set.
 		 */
-		bool getValue();
+		bool getValue() /* TODO(macbishop) should be const */;
+
+		/**
+		 * A SwitchArg can be used as a boolean, indicating
+		 * whether or not the switch has been set. This is the
+		 * same as calling getValue()
+		 */
+		operator bool() const { return _value; }
 		
 		virtual void reset();
 

include/tclap/ValueArg.h

@@ -220,7 +220,13 @@ class ValueArg : public Arg
         /**
          * Returns the value of the argument.
          */
-        T& getValue() ;
+	/* const */ T& getValue() /* TODO(macbishop): should be const */;
+
+    /**
+     * A ValueArg can be used as as its value type (T) This is the
+     * same as calling getValue()
+     */
+    operator const T&() const { return _value; }
 
         /**
          * Specialization of shortID.
@@ -308,7 +314,8 @@ ValueArg<T>::ValueArg(const std::string& flag,
 : Arg(flag, name, desc, req, true, v),
   _value( val ),
   _default( val ),
-  _typeDesc( constraint->shortID() ),
+  _typeDesc( constraint->shortID() ),  // TODO(macbishop): Will crash
+									   // if constraint is NULL
   _constraint( constraint )
 { 
     parser.add( this );

tests/test88.out

@@ -0,0 +1,4 @@
+for falseSwitch we got : 0
+for trueSwitch we got : 1
+for strArg we got : defStr
+for intArg we got : 4711

tests/test88.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+../examples/test27 -v "1 2 3" > tmp.out 2>&1
+
+if cmp -s tmp.out $srcdir/test88.out; then
+	exit 0
+else
+	exit 1
+fi