Runtime Error in rust-rewrite

[Compro-Prasad]

cargo build passes with a couple warnings.
Using Arch Linux.

Error(Alt) at l.48 by ' ws ! (
alt ! (
object => { | o | VDFValue :: Object ( o ) } | string => {
| s | VDFValue :: Str ( s ) } ) ) '
Error(Char) at l.62 by ' ws ! (
map ! (
pair ! ( string , object ) , | ( k , v ) | VDFValue :: Object (
singleton ( k , VDFValue :: Object ( v ) ) ) ) ) '
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Char', src/libcore/result.rs:999:5
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:59
             at src/libstd/panicking.rs:197
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:211
   4: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:474
   5: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:381
   6: rust_begin_unwind
             at src/libstd/panicking.rs:308
   7: core::panicking::panic_fmt
             at src/libcore/panicking.rs:85
   8: core::result::unwrap_failed
             at /rustc/7c71bc3208031b1307573de45a3b3e18fa45787a/src/libcore/macros.rs:18
   9: core::result::Result<T,E>::unwrap
             at /rustc/7c71bc3208031b1307573de45a3b3e18fa45787a/src/libcore/result.rs:800
  10: steamcurses::vdf::vdf_parser::parse_vdf
             at src/vdf/vdf_parser.rs:72
  11: steamcurses::parse_manifest
             at src/main.rs:29
  12: steamcurses::parse_manifests
             at src/main.rs:40
  13: steamcurses::main
             at src/main.rs:113
  14: std::rt::lang_start::{{closure}}
             at /rustc/7c71bc3208031b1307573de45a3b3e18fa45787a/src/libstd/rt.rs:64
  15: std::panicking::try::do_call
             at src/libstd/rt.rs:49
             at src/libstd/panicking.rs:293
  16: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:85
  17: std::rt::lang_start_internal
             at src/libstd/panicking.rs:272
             at src/libstd/panic.rs:388
             at src/libstd/rt.rs:48
  18: std::rt::lang_start
             at /rustc/7c71bc3208031b1307573de45a3b3e18fa45787a/src/libstd/rt.rs:64
  19: main
  20: __libc_start_main
  21: _start

Cargo version: 1.36.0-nightly (6be12653d 2019-04-19)
$XDG_CONFIG_HOME is empty.
I have used it as: RUST_BACKTRACE=1 ./target/debug/steamcurses
I don't have config file. How to create one?