def _nt_prefix
start_index = index
if node_cache[:prefix].has_key?(index)
cached = node_cache[:prefix][index]
if cached
node_cache[:prefix][index] = cached = SyntaxNode.new(input, index...(index + 1)) if cached == true
@index = cached.interval.end
end
return cached
end
i0 = index
if (match_len = has_terminal?('&', false, index))
r1 = instantiate_node(AndPredicate,input, index...(index + match_len))
@index += match_len
else
terminal_parse_failure('\'&\'')
r1 = nil
end
if r1
r1 = SyntaxNode.new(input, (index-1)...index) if r1 == true
r0 = r1
else
if (match_len = has_terminal?('!', false, index))
r2 = instantiate_node(NotPredicate,input, index...(index + match_len))
@index += match_len
else
terminal_parse_failure('\'!\'')
r2 = nil
end
if r2
r2 = SyntaxNode.new(input, (index-1)...index) if r2 == true
r0 = r2
else
if (match_len = has_terminal?('~', false, index))
r3 = instantiate_node(TransientPrefix,input, index...(index + match_len))
@index += match_len
else
terminal_parse_failure('\'~\'')
r3 = nil
end
if r3
r3 = SyntaxNode.new(input, (index-1)...index) if r3 == true
r0 = r3
else
@index = i0
r0 = nil
end
end
end
node_cache[:prefix][start_index] = r0
r0
end