Free Pascal Compiler version 3.0.0 [2015/11/16] for i386
Copyright (c) 1993-2015 by Florian Klaempfl and others
Target OS: Win32 for i386
Compiling foo.pas
foo.pas(19,17) Error: Identifier not found "len"
foo.pas(51,40) Warning: Variable "n" does not seem to be initialized
foo.pas(54,4) Fatal: There were 1 errors compiling module, stopping
Fatal: Compilation aborted
Error: C:\FPC\3.0.0\bin\i386-win32\ppc386.exe returned an error exitcode