Bug: This crash when enter some keys of keyboard

[Max Base]

Hello,

It's a funny project? You need to fix the problems.
Anyway, i find a bug and problem in this, so while are you trying to enter some keys. it will crash.

[max@base vid]$ ./vid config.v

['./vid', 'config.v']
PATH="config.v" cur_dir="/home/max/v/examples/vid"
add_workspace(".")
open file "config.v"
getting words
saving session...
load session "/home/max/.vid/session"
['config.v', '']
open file "config.v"
getting words
saving session...
V panic: substr(1, 0) out of bounds (len=21)
                                               | 0x5629655041c2 | ./vid(+0x161c2) 
                                               | 0x56296551b4ea | ./vid(+0x2d4ea) 
                                               | 0x56296551de74 | ./vid(+0x2fe74) 
                                               | 0x56296551ad54 | ./vid(+0x2cd54) 
                                               | 0x562965519dfa | ./vid(+0x2bdfa) 
                                               | 0x7f4761f4e0b6 | /usr/lib/libglfw.so.3(+0x170b6) 
                                               | 0x562965511e28 | ./vid(+0x23e28) 
                                               | 0x56296552bd65 | ./vid(+0x3dd65) 
                                               | 0x7f4761c2b023 | /usr/lib/libc.so.6(__libc_start_main+0xf3) 
                                               | 0x5629654f19de | ./vid(+0x39de) 

Regards,
Max Base

[JalonSolov]

ved compiles and runs fine on both Windows and Ubuntu Linux using the latest version of V.