# File lib/mail/parsers/rfc2822.rb, line 14 def _nt_ALPHA start_index = index if node_cache[:ALPHA].has_key?(index) cached = node_cache[:ALPHA][index] @index = cached.interval.end if cached return cached end if has_terminal?('\G[a-zA-Z]', true, index) r0 = instantiate_node(SyntaxNode,input, index...(index + 1)) @index += 1 else r0 = nil end node_cache[:ALPHA][start_index] = r0 r0 end