ENH: Added COMPARE modes to STRING command.

Source/cmStringCommand.cxx

@@ -30,6 +30,10 @@ bool cmStringCommand::InitialPass(std::vector<std::string> const& args)
     {
     return this->HandleRegexCommand(args);
     }  
+  else if(subCommand == "COMPARE")
+    {
+    return this->HandleCompareCommand(args);
+    }  
   
   std::string e = "does not recognize sub-command "+subCommand;
   this->SetError(e.c_str());
@@ -307,3 +311,59 @@ bool cmStringCommand::RegexReplace(std::vector<std::string> const& args)
   m_Makefile->AddDefinition(outvar.c_str(), output.c_str());
   return true;
 }
+
+//----------------------------------------------------------------------------
+bool cmStringCommand::HandleCompareCommand(std::vector<std::string> const& args)
+{
+  if(args.size() < 2)
+    {
+    this->SetError("sub-command COMPARE requires a mode to be specified.");
+    return false;
+    }
+  std::string mode = args[1];
+  if((mode == "EQUAL") || (mode == "NOTEQUAL") ||
+     (mode == "LESS") || (mode == "GREATER"))
+    {
+    if(args.size() < 5)
+      {
+      std::string e = "sub-command COMPARE, mode ";
+      e += mode;
+      e += " needs at least 5 arguments total to command.";
+      this->SetError(e.c_str());
+      return false;
+      }
+    
+    const std::string& left = args[2];
+    const std::string& right = args[3];  
+    const std::string& outvar = args[4];
+    bool result;
+    if(mode == "LESS")
+      {
+      result = (left < right);
+      }
+    else if(mode == "GREATER")
+      {
+      result = (left > right);
+      }
+    else if(mode == "EQUAL")
+      {
+      result = (left == right);
+      }
+    else // if(mode == "NOTEQUAL")
+      {
+      result = !(left == right);
+      }
+    if(result)
+      {
+      m_Makefile->AddDefinition(outvar.c_str(), "1");
+      }
+    else
+      {
+      m_Makefile->AddDefinition(outvar.c_str(), "0");
+      }
+    return true;
+    }  
+  std::string e = "sub-command COMPARE does not recognize mode "+mode;
+  this->SetError(e.c_str());
+  return false;
+}

Source/cmStringCommand.h

@@ -63,11 +63,16 @@ public:
       "STRING(REGEX MATCH <regular_expression> <output variable> <input> [<input>...])\n"
       "STRING(REGEX MATCHALL <regular_expression> <output variable> <input> [<input>...])\n"
       "STRING(REGEX REPLACE <regular_expression> <replace_expression> <output variable> <input> [<input>...])\n"
+      "STRING(COMPARE EQUAL <string1> <string2> <output variable>)\n"
+      "STRING(COMPARE NOTEQUAL <string1> <string2> <output variable>)\n"
+      "STRING(COMPARE LESS <string1> <string2> <output variable>)\n"
+      "STRING(COMPARE GREATER <string1> <string2> <output variable>)\n"
       "REGEX MATCH will match the regular expression once and store the match in the output variable.\n"  
       "REGEX MATCHALL will match the regular expression as many times as possible and store the matches\n"
       "               in the output variable as a list.\n"
       "REGEX REPLACE will match the regular expression as many times as possible and substitute the\n"
-      "              replacement expression for the match in the output.\n";
+      "              replacement expression for the match in the output.\n"
+      "COMPARE EQUAL/NOTEQUAL/LESS/GREATER will compare the strings and store true or false in the output variable.\n";
     }
   
   cmTypeMacro(cmStringCommand, cmCommand);
@@ -76,6 +81,7 @@ protected:
   bool RegexMatch(std::vector<std::string> const& args);
   bool RegexMatchAll(std::vector<std::string> const& args);
   bool RegexReplace(std::vector<std::string> const& args);
+  bool HandleCompareCommand(std::vector<std::string> const& args);
   
   class RegexReplacement
   {