Crash on large result

[hepek]

When an expression value is large enough the application crashes.

> 2000000000*200000000*20000000
thread 'main' panicked at 'index out of bounds: the len is 36 but the index is 9223372036854775808', /rustc/3c235d5600393dfe6c36eeed34042efad8d4f26e/src/libcore/slice/mod.rs:2686:10
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::panicking::panic_bounds_check
             at src/libcore/panicking.rs:61
   9: eva::format::pprint
  10: eva::main
  11: std::rt::lang_start::{{closure}}
  12: std::panicking::try::do_call
             at src/libstd/rt.rs:49
             at src/libstd/panicking.rs:293
  13: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:87
  14: std::rt::lang_start_internal
             at src/libstd/panicking.rs:272
             at src/libstd/panic.rs:388
             at src/libstd/rt.rs:48
  15: main
  16: __libc_start_main
  17: _start

[hepek]

src/format/mod.rs:38

let mut integral = number.abs().trunc() as i64;

will overflow if number is greater than 2^63+1 giving negative number, which then breaks the modulo indexing logic down at line 41.

[hepek]

here's a pull request for this problem: #20

Really like the project, btw. Keep up the good work.

[nerdypepper]

sweet! thank you so much for the contribution, ive been meaning to handle this panic for a while, with something like bigint!

closed by #20