isbra : string -> bool

SYNOPSIS
Tests if a one-character string is some kind of bracket.

DESCRIPTION
The call isbra s tests whether the first character of string s (normally it is the only character) is a bracket, meaning an opening or closing parenthesis, square bracket or curly brace.

FAILURE CONDITIONS
Fails if the string is empty.

SEE ALSO
isalnum, isalpha, isnum, issep, isspace, issymb.