Fixed a bug when the scanner parses a number and creates the token.

scanner.c

@@ -1,5 +1,6 @@
 #include "scanner.h"
 #include "token.h"
+#include <string.h>
 
 const char* source_code;
 //Start and Current hold the offsets that index into the string source_code.
@@ -245,9 +246,17 @@ void ParseNumber(TokenList* list) {
     }
 
     snprintf(lexeme, current - start, "%s", &source_code[start]);
-    double value = atof(lexeme); //Will this reference become stale on return?
+    double* value = calloc(1, sizeof(double));
+
+    if (!value) {
+        fprintf(stderr, "Failed to calloc for number value. %s\n", strerror(errno));
+        free(lexeme);
+        return;
+    }
+
+    *value = atof(lexeme);
     
-    AddToTokenList(CreateToken(lexeme, &value, line, Number), list);
+    AddToTokenList(CreateToken(lexeme, value, line, Number), list);
 }
 
 char PeekNext() {