allow to specify a node type: --prop:[type:]name=value

where type is one of string (default), double, float, long, int, bool
Using only the first letter works, too.

  --prop:foo=123         ... sets property foo to string 123 (old behavior)
  --prop:string:foo=123  ... verbose version of above
  --prop:s:foo=123       ... slightly less verbose version of above
  --prop:bool:foo=1      ... makes property a bool of value 'true'

I hope this isn't considered a silly gimmick. I need this often and maybe
other developers do, too. It's useful in cases where the difference really
matters. if (getprop("/foo")), for instance, is TRUE even when the property
contains string "false", as all strings are TRUE.

diff --git a/src/Main/options.cxx b/src/Main/options.cxx
index 37f2d46304e9fcda53643bad75421378cd8e2955..a32745ce327c9f5e6ab465e992b4a4d845fd1622 100644 (file)
--- a/src/Main/options.cxx
+++ b/src/Main/options.cxx
@@ -1398,6 +1398,46 @@ struct OptionDesc {
 };
 
 
+// Set a property for the --prop: option. Syntax: --prop:[<type>:]<name>=<value>
+// <type> can be "double" etc. but also only the first letter "d".
+// Examples:  --prop:alpha=1  --prop:bool:beta=true  --prop:d:gamma=0.123
+static bool
+set_property(const string& arg)
+{
+    string::size_type pos = arg.find('=');
+    if (pos == arg.npos || pos == 0 || pos + 1 == arg.size())
+        return false;
+
+    string name = arg.substr(0, pos);
+    string value = arg.substr(pos + 1);
+    string type = "string";
+    pos = name.find(':');
+    if (pos != name.npos && pos != 0 && pos + 1 != name.size()) {
+        type = name.substr(0, pos);
+        name = name.substr(pos + 1);
+    }
+    if (type == "s" || type == "string") {
+        fgSetString(name.c_str(), value.c_str());
+        return true;
+    }
+    if (type == "d" || type == "double")
+        fgSetDouble(name.c_str(), 0.0);
+    else if (type == "f" || type == "float")
+        fgSetFloat(name.c_str(), 0.0f);
+    else if (type == "l" || type == "long")
+        fgSetLong(name.c_str(), 0L);
+    else if (type == "i" || type == "int")
+        fgSetInt(name.c_str(), 0);
+    else if (type == "b" || type == "bool")
+        fgSetBool(name.c_str(), false);
+    else
+        return false;
+
+    fgSetString(name.c_str(), value.c_str());
+    return true;
+}
+
+
 // Parse a single option
 static int
 parse_option (const string& arg)
@@ -1422,15 +1462,9 @@ parse_option (const string& arg)
     } else if ( arg.find( "--show-aircraft") == 0) {
         return(FG_OPTIONS_SHOW_AIRCRAFT);
     } else if ( arg.find( "--prop:" ) == 0 ) {
-        string assign = arg.substr(7);
-       string::size_type pos = assign.find('=');
-       if ( pos == arg.npos || pos == 0 || pos + 1 == assign.size() ) {
-           SG_LOG( SG_GENERAL, SG_ALERT, "Bad property assignment: " << arg );
+        if (!set_property(arg.substr(7))) {
+            SG_LOG( SG_GENERAL, SG_ALERT, "Bad property assignment: " << arg );
             return FG_OPTIONS_ERROR;
-        } else {
-           string name = assign.substr(0, pos);
-           string value = assign.substr(pos + 1);
-           fgSetString(name.c_str(), value.c_str());
         }
     } else if ( arg.find( "--" ) == 0 ) {
         size_t pos = arg.find( '=' );