Are some stuff missing in mql4 book?

[Deleted]  
Today i got a never seen before error when i tried to compile. It read like this "Variable name too long". I dont recall reading anything like maximum variable name length in mql4 book. Could this mean some things weren't published in the book?
 

From the Documentation

Identifiers

Identifiers are used as names of variables, functions, and data types. The length of an identifier cannot exceed 31 character..