Add a "gn help all" option to GN to print all of the help at once.

tools/gn/command_help.cc

Index: tools/gn/command_help.cc
diff --git a/tools/gn/command_help.cc b/tools/gn/command_help.cc
index 0f8c34790a7d593dff32f67014c13b532fbdc3a9..9faf338b6fd91ee481fa649b25b180be733e0aac 100644
--- a/tools/gn/command_help.cc
+++ b/tools/gn/command_help.cc
@@ -56,6 +56,7 @@ void PrintToplevelHelp() {
     PrintShortHelp(target.second.help_short);
 
   OutputString("\nOther help topics:\n");
+  PrintShortHelp("all: Print all the help at once");
   PrintShortHelp("buildargs: How build arguments work.");
   PrintShortHelp("dotfile: Info about the toplevel .gn file.");
   PrintShortHelp("label_pattern: Matching more than one label.");
@@ -76,6 +77,39 @@ void PrintSwitchHelp() {
     PrintShortHelp(s.second.short_help);
 }
 
+void PrintAllHelp() {
+  PrintToplevelHelp();
+
+  for (const auto& s : switches::GetSwitches()) {

[brettw, 2015/04/16 23:35:13]

No {} for these loops

[Dirk Pranke, 2015/04/16 23:36:50]

ah, right.

+    PrintLongHelp(s.second.long_help);
+  }
+
+  for (const auto& c: commands::GetCommands()) {

[brettw, 2015/04/16 23:35:13]

Space before the colon for these loops.

[Dirk Pranke, 2015/04/16 23:36:50]

Acknowledged.

+    PrintLongHelp(c.second.help);
+  }
+
+  for (const auto& f: functions::GetFunctions()) {
+    PrintLongHelp(f.second.help);
+  }
+
+  for (const auto& v: variables::GetBuiltinVariables()) {
+    PrintLongHelp(v.second.help);
+  }
+
+  for (const auto& v: variables::GetTargetVariables()) {
+    PrintLongHelp(v.second.help);
+  }
+
+  PrintLongHelp(kBuildArgs_Help);
+  PrintLongHelp(kDotfile_Help);
+  PrintLongHelp(kInputConversion_Help);
+  PrintLongHelp(kLabelPattern_Help);
+  PrintLongHelp(kSourceExpansion_Help);
+  PrintSwitchHelp();
+}
+
+

[brettw, 2015/04/16 23:35:13]

Got some extra blank lines in here (should just be one)

[Dirk Pranke, 2015/04/16 23:36:50]

Acknowledged.

+
 // Prints help on the given switch. There should be no leading hyphens. Returns
 // true if the switch was found and help was printed. False means the switch is
 // unknown.
@@ -161,6 +195,10 @@ int RunHelp(const std::vector<std::string>& args) {
   }
 
   // Random other topics.
+  if (what == "all") {
+    PrintAllHelp();
+    return 0;
+  }
   if (what == "buildargs") {
     PrintLongHelp(kBuildArgs_Help);
     return 0;