def _nt_alpha_char
start_index = index
if node_cache[:alpha_char].has_key?(index)
cached = node_cache[:alpha_char][index]
if cached
node_cache[:alpha_char][index] = cached = SyntaxNode.new(input, index...(index + 1)) if cached == true
@index = cached.interval.end
end
return cached
end
if has_terminal?(@regexps[gr = '\A[A-Za-z_]'] ||= Regexp.new(gr), :regexp, index)
r0 = instantiate_node(SyntaxNode,input, index...(index + 1))
@index += 1
else
terminal_parse_failure('[A-Za-z_]')
r0 = nil
end
node_cache[:alpha_char][start_index] = r0
r0
end