New call api.addAllowed() to add values to a field's allowed value list

src/base/api.lua

@@ -74,6 +74,36 @@
 	end
 
 
+--
+-- Add a new value to a field's list of allowed values.
+--
+-- @param fieldName
+--    The name of the field to which to add the value.
+-- @param value
+--    The value to add. May be a single string value, or an array
+--    of values.
+--
+
+	function api.addAllowed(fieldName, value)
+		local field = premake.fields[fieldName]
+		if not field then
+			error("No such field: " .. fieldName, 2)
+		end
+
+		if not field.allowed then
+			field.allowed = {}
+		end
+
+		if type(value) == "table" then
+			field.allowed = table.join(field.allowed, value)
+		else
+			table.insert(field.allowed, value)
+		end
+
+		table.sort(field.allowed)
+	end
+
+
 --
 -- Find the right target object for a given scope.
 --