env has to start with letter

main.go

@@ -1,6 +1,7 @@
 package envconf
 
 import ("strings"
+        "unicode"
         "os")
 
 const TypeNone = (1 << 1)
@@ -13,17 +14,26 @@ type Config struct {
 
 }
 
+func getFirstRune(str string)(rune) {
+    for _,v := range str {
+        return v
+    }
+    return rune(0)
+}
+
 func NewConfig()(*Config) {
     config := new(Config)
     config.env = make(map[string]map[string]int)
     for _,v := range os.Environ() {
         splitted := strings.SplitN(v, "=", 2)
         if len(splitted) == 2 {
-            key := strings.ToLower(splitted[0])
-            strval := splitted[1]
-            val := make(map[string]int)
-            val[strval] = TypeNone
-            config.env[key] = val
+            key := strings.TrimSpace(strings.ToLower(splitted[0]))
+            if unicode.IsLetter(getFirstRune(key)) {
+                strval := splitted[1]
+                val := make(map[string]int)
+                val[strval] = TypeNone
+                config.env[key] = val
+            }
         }
     }
     return config