mu/lib/utils/mu-command-handler.hh

296 lines
7.9 KiB
C++

/*
** Copyright (C) 2020-2022 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
** This program is free software; you can redistribute it and/or modify it
** under the terms of the GNU General Public License as published by the
** Free Software Foundation; either version 3, or (at your option) any
** later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software Foundation,
** Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**
*/
#ifndef MU_COMMAND_HANDLER_HH__
#define MU_COMMAND_HANDLER_HH__
#include <vector>
#include <string>
#include <ostream>
#include <stdexcept>
#include <unordered_map>
#include <functional>
#include <algorithm>
#include "utils/mu-error.hh"
#include "utils/mu-sexp.hh"
#include "utils/mu-option.hh"
namespace Mu {
///
/// Commands are s-expressions with the follow properties:
/// 1) a command is a list with a command-name as its first argument
/// 2) the rest of the parameters are pairs of colon-prefixed symbol and a value of some
/// type (ie. 'keyword arguments')
/// 3) each command is described by its CommandInfo structure, which defines the type
/// 4) calls to the command must include all required parameters
/// 5) all parameters must be of the specified type; however the symbol 'nil' is allowed
/// for specify a non-required parameter to be absent; this is for convenience on the
/// call side.
struct Command: public Sexp {
static Result<Command> make(Sexp&& sexp) try {
return Ok(Command{std::move(sexp)});
} catch (const Error& e) {
return Err(e);
}
static Result<Command> make_parse(const std::string& cmdstr) try {
if (auto&& sexp{Sexp::parse(cmdstr)}; !sexp)
return Err(sexp.error());
else
return Ok(Command(std::move(*sexp)));
} catch (const Error& e) {
return Err(e);
}
/**
* Get name of the command (first element) in a command exp
*
* @return name
*/
const std::string& name() const {
return cbegin()->symbol().name;
}
/**
* Find the argument with the given name.
*
* @param arg name
*
* @return iterator point at the argument, or cend
*/
const_iterator find_arg(const std::string& arg) const {
return find_prop(arg, cbegin() + 1, cend());
}
/**
* Get a string argument
*
* @param name of the argument
*
* @return ref to string, or Nothing if not found
*/
Option<const std::string&> string_arg(const std::string& name) const {
if (auto&& val{arg_val(name, Sexp::Type::String)}; !val)
return Nothing;
else
return val->string();
}
/**
* Get a string-vec argument
*
* @param name of the argument
*
* @return ref to string-vec, or Nothing if not found or some error.
*/
Option<std::vector<std::string>> string_vec_arg(const std::string& name) const;
/**
* Get a symbol argument
*
* @param name of the argument
*
* @return ref to symbol name, or Nothing if not found
*/
Option<const std::string&> symbol_arg(const std::string& name) const {
if (auto&& val{arg_val(name, Sexp::Type::Symbol)}; !val)
return Nothing;
else
return val->symbol().name;
}
/**
* Get a number argument
*
* @param name of the argument
*
* @return number or Nothing if not found
*/
Option<int> number_arg(const std::string& name) const {
if (auto&& val{arg_val(name, Sexp::Type::Number)}; !val)
return Nothing;
else
return static_cast<int>(val->number());
}
/*
* helpers
*/
/**
* Get a boolean argument
*
* @param name of the argument
*
* @return true if there's a non-nil symbol value for the given
* name; false otherwise.
*/
Option<bool> bool_arg(const std::string& name) const {
if (auto&& symb{symbol_arg(name)}; !symb)
return Nothing;
else
return symb.value() == "nil" ? false : true;
}
/**
* Treat any argument as a boolean
*
* @param name name of the argument
*
* @return false if the the argument is absent or the symbol false;
* otherwise true.
*/
bool boolean_arg(const std::string& name) const {
auto&& it{find_arg(name)};
return (it == cend() || std::next(it)->nilp()) ? false : true;
}
private:
explicit Command(Sexp&& s){
*this = std::move(static_cast<Command&&>(s));
if (!listp() || empty() || !cbegin()->symbolp() ||
!plistp(cbegin() + 1, cend()))
throw Error(Error::Code::Command,
"expected command, got '%s'", to_string().c_str());
}
Option<const Sexp&> arg_val(const std::string& name, Sexp::Type type) const {
if (auto&& it{find_arg(name)}; it == cend()) {
//std::cerr << "--> %s name found " << name << '\n';
return Nothing;
} else if (auto&& val{it + 1}; val->type() != type) {
//std::cerr << "--> type " << Sexp::type_name(it->type()) << '\n';
return Nothing;
} else
return *val;
}
};
struct CommandHandler {
/// Information about a function argument
struct ArgInfo {
ArgInfo(Sexp::Type typearg, bool requiredarg, std::string&& docarg)
: type{typearg}, required{requiredarg}, docstring{std::move(docarg)} {}
const Sexp::Type type; /**< Sexp::Type of the argument */
const bool required; /**< Is this argument required? */
const std::string docstring; /**< Documentation */
};
/// The arguments for a function, which maps their names to the information.
using ArgMap = std::unordered_map<std::string, ArgInfo>;
// A handler function
using Handler = std::function<void(const Command&)>;
/// Information about some command
struct CommandInfo {
CommandInfo(ArgMap&& argmaparg, std::string&& docarg, Handler&& handlerarg)
: args{std::move(argmaparg)}, docstring{std::move(docarg)},
handler{std::move(handlerarg)} {}
const ArgMap args;
const std::string docstring;
const Handler handler;
/**
* Get a sorted list of argument names, for display. Required args come
* first, then alphabetical.
*
* @return vec with the sorted names.
*/
std::vector<std::string> sorted_argnames() const {
// sort args -- by required, then alphabetical.
std::vector<std::string> names;
for (auto&& arg : args)
names.emplace_back(arg.first);
std::sort(names.begin(), names.end(), [&](const auto& name1, const auto& name2) {
const auto& arg1{args.find(name1)->second};
const auto& arg2{args.find(name2)->second};
if (arg1.required != arg2.required)
return arg1.required;
else
return name1 < name2;
});
return names;
}
};
/// All commands, mapping their name to information about them.
using CommandInfoMap = std::unordered_map<std::string, CommandInfo>;
CommandHandler(const CommandInfoMap& cmap): cmap_{cmap} {}
CommandHandler(CommandInfoMap&& cmap): cmap_{std::move(cmap)} {}
const CommandInfoMap& info_map() const { return cmap_; }
/**
* Invoke some command
*
* A command uses keyword arguments, e.g. something like: (foo :bar 1
* :cuux "fnorb")
*
* @param cmd a Sexp describing a command call
* @param validate whether to validate before invoking. Useful during
* development.
*
* Return Ok() or some Error
*/
Result<void> invoke(const Command& cmd, bool validate=true) const;
private:
const CommandInfoMap cmap_;
};
static inline std::ostream&
operator<<(std::ostream& os, const CommandHandler::ArgInfo& info)
{
os << info.type << " (" << (info.required ? "required" : "optional") << ")";
return os;
}
static inline std::ostream&
operator<<(std::ostream& os, const CommandHandler::CommandInfo& info)
{
for (auto&& arg : info.args)
os << " " << arg.first << " " << arg.second << '\n'
<< " " << arg.second.docstring << "\n";
return os;
}
static inline std::ostream&
operator<<(std::ostream& os, const CommandHandler::CommandInfoMap& map)
{
for (auto&& c : map)
os << c.first << '\n' << c.second;
return os;
}
} // namespace Mu
#endif /* MU_COMMAND_HANDLER_HH__ */