home/src/parameters_parser.cc
aver-d f43635c4df Ease reading of command-line options
This change displays command-line options in grid format. Each
parameter is indented with two spaces and then padded to maintain
vertical alignment of each description.

I think the visual spacing makes the options much easier to
read. This is particularly important for people new to Kakoune who
use `-help` as a way to become familiar with the program.
2018-02-25 01:46:50 +00:00

87 lines
2.6 KiB
C++

#include "parameters_parser.hh"
#include "flags.hh"
namespace Kakoune
{
String generate_switches_doc(const SwitchMap& switches)
{
Vector<int> lengths(switches.size());
int i = 0;
for (auto& sw : switches) {
lengths[i++] = (int)sw.key.length() + (sw.value.takes_arg ? 5: 0);
}
int maxlen = *std::max_element(lengths.begin(), lengths.end());
String res;
i = 0;
for (auto& sw : switches) {
int len = lengths[i++];
String pad = " ";
while (len++ < maxlen)
pad += ' ';
res += format(" -{} {}{}{}\n",
sw.key,
sw.value.takes_arg ? "<arg>" : "",
pad,
sw.value.description);
}
return res;
}
ParametersParser::ParametersParser(ParameterList params,
const ParameterDesc& desc)
: m_params(params),
m_desc(desc)
{
bool only_pos = desc.flags & ParameterDesc::Flags::SwitchesAsPositional;
Vector<bool> switch_seen(desc.switches.size(), false);
for (size_t i = 0; i < params.size(); ++i)
{
if (not only_pos and params[i] == "--")
only_pos = true;
else if (not only_pos and not params[i].empty() and params[i][0_byte] == '-')
{
auto it = m_desc.switches.find(params[i].substr(1_byte));
if (it == m_desc.switches.end())
throw unknown_option(params[i]);
auto switch_index = it - m_desc.switches.begin();
if (switch_seen[switch_index])
throw runtime_error{format("switch '-{}' specified more than once", it->key)};
switch_seen[switch_index] = true;
if (it->value.takes_arg and ++i == params.size())
throw missing_option_value(it->key);
}
else // positional
{
if (desc.flags & ParameterDesc::Flags::SwitchesOnlyAtStart)
only_pos = true;
m_positional_indices.push_back(i);
}
}
size_t count = m_positional_indices.size();
if (count > desc.max_positionals or count < desc.min_positionals)
throw wrong_argument_count();
}
Optional<StringView> ParametersParser::get_switch(StringView name) const
{
auto it = m_desc.switches.find(name);
kak_assert(it != m_desc.switches.end());
for (size_t i = 0; i < m_params.size(); ++i)
{
const auto& param = m_params[i];
if (param[0_byte] == '-' and param.substr(1_byte) == name)
return it->value.takes_arg ? m_params[i+1] : StringView{};
if (param == "--")
break;
}
return {};
}
}