Added bool operator to astring, returning true if the string is

not empty. Conveniently, this creates ambiguity if you write
astring == NULL. Rooted out remaining cases where we were doing
that and fixed them.

src/emu/cheat.c

@@ -518,7 +518,7 @@ void cheat_render_text(running_machine *machine, render_container *container)
 
 		/* render any text and free it along the way */
 		for (linenum = 0; linenum < ARRAY_LENGTH(cheatinfo->output); linenum++)
-			if (cheatinfo->output[linenum].len() != 0)
+			if (cheatinfo->output[linenum])
 			{
 				/* output the text */
 				ui_draw_text_full(container, cheatinfo->output[linenum],
@@ -956,7 +956,7 @@ static void cheat_execute_script(cheat_private *cheatinfo, cheat_entry *cheat, s
 		}
 
 		/* if there is a string to display, compute it */
-		if (entry->format.len() != 0)
+		if (entry->format)
 		{
 			UINT64 params[MAX_ARGUMENTS];
 			output_argument *arg;
@@ -1283,14 +1283,14 @@ static void cheat_entry_save(mame_file *cheatfile, const cheat_entry *cheat)
 	mame_fprintf(cheatfile, "\t<cheat desc=\"%s\"", cheat->description.cstr());
 	if (cheat->numtemp != DEFAULT_TEMP_VARIABLES)
 		mame_fprintf(cheatfile, " tempvariables=\"%d\"", cheat->numtemp);
-	if (cheat->comment.len() == 0 && cheat->parameter == NULL && scriptcount == 0)
+	if (!cheat->comment && cheat->parameter == NULL && scriptcount == 0)
 		mame_fprintf(cheatfile, " />\n");
 	else
 	{
 		mame_fprintf(cheatfile, ">\n");
 
 		/* save the comment */
-		if (cheat->comment.len() != 0)
+		if (cheat->comment)
 			mame_fprintf(cheatfile, "\t\t<comment><![CDATA[\n%s\n\t\t]]></comment>\n", cheat->comment.cstr());
 
 		/* output the parameter, if present */
@@ -1704,7 +1704,7 @@ static void script_entry_save(mame_file *cheatfile, const script_entry *entry)
 	astring tempstring;
 
 	/* output an action */
-	if (entry->format.len() == 0)
+	if (!entry->format)
 	{
 		mame_fprintf(cheatfile, "\t\t\t<action");
 		if (entry->condition != NULL)

src/emu/debug/debugcpu.c

@@ -2557,7 +2557,7 @@ void device_debug::breakpoint_check(offs_t pc)
 			global->execution_state = EXECUTION_STATE_STOPPED;
 
 			// if we hit, evaluate the action
-			if (bp->m_action.len() != 0)
+			if (bp->m_action)
 				debug_console_execute_command(m_device.machine, bp->m_action, 0);
 
 			// print a notification, unless the action made us go again
@@ -2650,7 +2650,7 @@ void device_debug::watchpoint_check(address_space &space, int type, offs_t addre
 			global->execution_state = EXECUTION_STATE_STOPPED;
 
 			// if we hit, evaluate the action
-			if (wp->m_action != NULL)
+			if (wp->m_action)
 				debug_console_execute_command(space.machine, wp->m_action, 0);
 
 			// print a notification, unless the action made us go again
@@ -3011,7 +3011,7 @@ void device_debug::tracer::update(offs_t pc)
 	m_loops = 0;
 
 	// execute any trace actions first
-	if (m_action != NULL)
+	if (m_action)
 		debug_console_execute_command(m_debug.m_device.machine, m_action, 0);
 
 	// print the address

src/emu/debugint/debugint.c

@@ -492,7 +492,7 @@ static void dview_draw_title(DView *dv)
 
 	dview_draw_outlined_box(dv, RECT_DVIEW_TITLE, 0, 0, rect_get_width(&dv->bounds), TITLE_HEIGHT, col);
 
-	if (dv->title == NULL)
+	if (!dv->title)
 		return;
 
 	for (i=0; i<strlen(dv->title); i++)

src/emu/mconfig.c

@@ -145,7 +145,7 @@ void machine_config::detokenize(const machine_config_token *tokens, const device
 
 			case MCONFIG_TOKEN_DEVICE_MODIFY:
 				tag = TOKEN_GET_STRING(tokens);
-				device = m_devicelist.find(owner->subtag(tempstring, tag));
+				device = m_devicelist.find(owner->subtag(tempstring, tag).cstr());
 				if (device == NULL)
 					fatalerror("Unable to find device: tag=%s\n", tempstring.cstr());
 				break;

src/lib/util/astring.h

@@ -333,6 +333,7 @@ public:
 	astring &reset() { return cpy(""); }
 	astring &expand(int length) { astring_expand(this, length); return *this; }
 
+	operator bool() const { return this->text[0] != 0; }
 	operator char *() { return this->text; }
 	operator const char *() const { return astring_c(this); }
 	const char *cstr() const { return astring_c(this); }