lib_core.h

#pragma once
 
#include "../eval.h"
#include <print>
 
namespace ghassanpl::eval
{
    template <bool DECADE_SYNTAX>
    struct base_lib
    {
        using enum nlohmann::json::value_t;
        static constexpr nlohmann::json::value_t any = nlohmann::json::value_t::discarded;
 
        using env_type = environment<DECADE_SYNTAX>;
        using json_pointer = nlohmann::json::json_pointer;
 
        static json_pointer make_pointer(json const& index)
        {
            json_pointer ptr;
            switch (index.type())
            {
            case string: ptr /= std::string{ index }; return ptr;
            case number_float: ptr /= int(float(index)); return ptr;
            case number_integer: ptr /= int(index); return ptr;
            case number_unsigned: ptr /= int(index); return ptr;
            case array: {
                for (auto& e : index)
                    ptr /= make_pointer(e);
                return ptr;
            }
            default: break;
            }
            throw std::runtime_error(std::format("invalid value index type '{}'", index.type_name()));
        }
 
    };
 
    template <bool DECADE_SYNTAX>
    struct lib_core : public base_lib<DECADE_SYNTAX>
    {
        using enum nlohmann::json::value_t;
 
        using base_type = base_lib<DECADE_SYNTAX>;
        using env_type = base_type::env_type;
        using json_pointer = base_type::json_pointer;
 
        static inline value if_then_else(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 3);
            if (e.is_true(e.eval_arg(args, 1)))
                return e.eval_arg(args, 2);
            return e.eval_arg(args, 3);
        }
 
        struct e_break : env_type::e_scope_terminator { virtual std::string_view type() const noexcept override { return "break"; } };
        struct e_continue : env_type::e_scope_terminator { virtual std::string_view type() const noexcept override { return "continue"; } };
 
        static inline value while_do(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 2);
            value last = null_json;
            while (e.is_true(e.eval(args[1])))
            {
                try
                {
                    last = e.eval(args[2]);
                }
                catch (e_break const& ex)
                {
                    if (!ex.result->is_discarded())
                        last = ex.result;
                    break;
                }
                catch (e_continue const& ex)
                {
                    if (!ex.result->is_discarded())
                        last = ex.result;
                    continue;
                }
            }
            return last;
        }
 
        static inline value while_do_rev(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 2);
            std::swap(args[1], args[2]);
            return while_do(e, std::move(args));
        }
 
        static inline value loop_break(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 0, 1);
            e_break ex{};
            if (args.size() == 2) ex.result = e.eval_arg(args, 1);
            throw ex;
        }
 
        static inline value var_get(env_type& e, std::vector<value> args)
        {
            auto name = e.eval_arg(args, 1, string);
            return e.user_var(*name);
        }
 
        static inline value var_set(env_type& e, std::vector<value> args)
        {
            auto var = e.eval_arg(args, 1);
            if (!var.is_lval())
                return e.report_error("trying to assign to a non-variable");
            var.lval() = e.eval_arg(args, 2).forward();
            return var;
        }
 
        static inline value new_var(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 2, 3);
            auto name = e.eval_arg(args, 1, string);
            auto val = args.size() == 3 ? e.eval_arg(args, 2) : value(null_json);
            return &e.set_user_var(*name, std::move(val), true);
        }
 
        static inline value get_of(env_type& e, std::vector<value> args)
        {
 
            e.eval_args(args, 2);
            const json_pointer index = base_type::make_pointer(args[1]);
            value& container = args[2];
            if (!container->contains(index))
                return null_json;
            switch (container.v.index())
            {
            case 0: return std::move(std::get<json>(container.v).at(index));
            case 1: return &std::get<json*>(container.v)->at(index);
            case 2: return &std::get<json const*>(container.v)->at(index);
            }
            return e.report_error("internal error: container value is invalid");
        }
 
        static inline value get_of_inv(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 2);
            std::swap(args[1], args[2]);
            return get_of(e, std::move(args));
        }
 
        static inline value eval(env_type& e, std::vector<value> args)
        {
            value last = null_json;
            for (auto& arg : std::span{ args }.subspan(1))
                last = e.eval(std::move(arg));
            return last;
        }
 
        static inline value list(env_type& e, std::vector<value> args)
        {
            e.eval_args(args);
            std::vector<json> result;
            for (auto& arg : std::span{ args }.subspan(1))
                result.push_back(arg.forward());
            return value(std::move(result));
        }
 
        static inline value quote(env_type& e, std::vector<value> args) { e.assert_args(args, 1); return std::move(args[1]); }
 
        static inline value op_eq(env_type& e, std::vector<value> args) { e.eval_args(args, 2);  return *args[1] == *args[2]; }
        static inline value op_neq(env_type& e, std::vector<value> args) { e.eval_args(args, 2); return *args[1] != *args[2]; }
        static inline value op_gt(env_type& e, std::vector<value> args) { e.eval_args(args, 2);  return *args[1] > *args[2]; }
        static inline value op_ge(env_type& e, std::vector<value> args) { e.eval_args(args, 2);  return *args[1] >= *args[2]; }
        static inline value op_lt(env_type& e, std::vector<value> args) { e.eval_args(args, 2);  return *args[1] < *args[2]; }
        static inline value op_le(env_type& e, std::vector<value> args) { e.eval_args(args, 2);  return *args[1] <= *args[2]; }
 
        static inline value op_not(env_type& e, std::vector<value> args) { e.eval_args(args, 1);  return !e.is_true(args[1]); }
        static inline value op_and(env_type& e, std::vector<value> args) {
            e.assert_min_args(args, 2);
            value left;
            for (size_t i = 1; i < args.size(); ++i)
            {
                left = e.eval_arg(args, i);
                if (!e.is_true(left))
                    return left;
            }
            return left;
        }
        static inline value op_or(env_type& e, std::vector<value> args) {
            e.assert_min_args(args, 2);
            value left;
            for (size_t i = 1; i < args.size(); ++i)
            {
                left = e.eval_arg(args, i);
                if (e.is_true(left))
                    return left;
            }
            return left;
        }
 
        static inline value op_plus(env_type& e, std::vector<value> args) { e.eval_args(args, 2);   return *args[1] + *args[2]; }
        static inline value op_minus(env_type& e, std::vector<value> args) { e.eval_args(args, 2);  return *args[1] - *args[2]; }
        static inline value op_mul(env_type& e, std::vector<value> args) { e.eval_args(args, 2);    return *args[1] * *args[2]; }
        static inline value op_div(env_type& e, std::vector<value> args) { e.eval_args(args, 2);    return *args[1] / *args[2]; }
        static inline value op_mod(env_type& e, std::vector<value> args) { e.eval_args(args, 2);    return *args[1] % *args[2]; }
 
        static inline value type_of(env_type& e, std::vector<value> args) {
            const auto val = e.eval_arg(args, 1);
            return val->type_name();
        }
        static inline value size_of(env_type& e, std::vector<value> args) {
            const auto val = e.eval_arg(args, 1);
            const json& j = val;
            return j.is_string() ? j.get_ref<json::string_t const&>().size() : j.size();
        }
 
        static inline std::string stringify(value const& arg, std::string_view fmt = "{}")
        {
            return ghassanpl::formats::json::visit(arg.ref(), [&](auto const& val) {
                if constexpr (std::is_same_v<std::remove_cvref_t<decltype(val)>, nlohmann::json::array_t>)
                    return std::vformat(fmt, std::make_format_args(arg->dump()));
                else if constexpr (std::is_same_v<std::remove_cvref_t<decltype(val)>, nlohmann::json::object_t>)
                    return std::vformat(fmt, std::make_format_args(arg->dump()));
                else if constexpr (std::is_same_v<std::remove_cvref_t<decltype(val)>, nlohmann::json::binary_t>)
                    return std::vformat(fmt, std::make_format_args(arg->dump()));
                else if constexpr (std::is_same_v<std::remove_cvref_t<decltype(val)>, nullptr_t>)
                    return "null"s;
                else
                    return std::vformat(fmt, std::make_format_args(val));
            });
        }
 
 
        static inline value str(env_type& e, std::vector<value> args)
        {
            auto arg = e.eval_arg(args, 1);
            return stringify(arg);
        }
 
        static inline value format(env_type& e, std::vector<value> args)
        {
            e.assert_min_args(args, 1);
            e.eval_args(args);
 
            return string_ops::callback_format(args[1].ref(), [&](size_t index, std::string_view fmt, std::string& output) {
                auto& arg = args[2 + index];
                output += stringify(arg, fmt);
            });
        }
 
        static inline value print(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 1);
            auto fmted = format(e, std::move(args));
            std::print("{}", fmted->template get_ref<nlohmann::json::string_t const&>());
            return null_json;
        }
 
        static inline value println(env_type& e, std::vector<value> args)
        {
            e.assert_args(args, 1);
            auto fmted = format(e, std::move(args));
            std::println("{}", fmted->template get_ref<nlohmann::json::string_t const&>());
            return null_json;
        }
 
        static inline json prefix_macro_get(env_type const&, std::vector<value> args) {
            return json{ "get", string_view{args[0]}.substr(1) };
        };
 
        static inline void set_macro_prefix_get(env_type& e, std::string const& prefix = ".", std::string const& prefix_eval_func_name = "dot", std::string const& get_func_name = "get")
        {
            e.prefix_macros[prefix] = [get_func_name, prefix_size = prefix.size()](env_type const& e, std::vector<value> args) {
                return json{ get_func_name, std::string{*args[0]}.substr(prefix_size) };
            };
            e.funcs[prefix_eval_func_name] = [prefix](env_type const& e, std::vector<value>) -> value {
                return prefix;
            };
        }
 
        static void import_to(env_type& e)
        {
            e.funcs["list"] = list;
            e.funcs["eval"] = eval;
            e.funcs["break"] = loop_break;
            set_macro_prefix_get(e);
 
            if constexpr (DECADE_SYNTAX)
            {
                e.funcs["if:then:else:"] = if_then_else;
                e.funcs[":?:::"] = if_then_else;
                e.funcs["while:do:"] = while_do;
                e.funcs[":while:"] = while_do_rev;
                e.funcs["break:"] = loop_break;
 
                e.funcs["get:"] = var_get;
                e.funcs["get:of:"] = get_of;
                e.funcs[":@:"] = get_of_inv;
                e.funcs[":at:"] = get_of_inv;
                e.funcs[":=:"] = var_set;
                e.funcs["var:"] = new_var;
                e.funcs["var:=:"] = new_var;
                e.funcs["list:"] = list;
                e.funcs["list:,:"] = list;
                e.funcs["list:,*:"] = list;
                e.funcs["eval:"] = eval;
                e.funcs["eval:,:"] = eval;
                e.funcs["eval:,*:"] = eval;
                e.funcs[":==:"] = op_eq;
                e.funcs[":eq:"] = op_eq;
                e.funcs[":!=:"] = op_neq;
                e.funcs[":neq:"] = op_neq;
                e.funcs[":>:"] = op_gt;
                e.funcs[":gt:"] = op_gt;
                e.funcs[":>=:"] = op_ge;
                e.funcs[":ge:"] = op_ge;
                e.funcs[":<:"] = op_lt;
                e.funcs[":lt:"] = op_lt;
                e.funcs[":<=:"] = op_le;
                e.funcs[":le:"] = op_le;
                e.funcs["not:"] = op_not;
                e.funcs[":and*:"] = op_and;
                e.funcs[":and:"] = op_and;
                e.funcs[":or:"] = op_or;
                e.funcs[":or*:"] = op_or;
                e.funcs[":+:"] = op_plus;
                e.funcs["type-of:"] = type_of;
                e.funcs["typeof:"] = type_of;
                e.funcs["size-of:"] = size_of;
                e.funcs["sizeof:"] = size_of;
                e.funcs["#:"] = size_of;
 
                e.funcs["str:"] = str;
 
                e.funcs["format:"] = format;
                e.funcs["format:,:"] = format;
                e.funcs["format:,*:"] = format;
 
                e.funcs["print:"] = print;
                e.funcs["print:,:"] = print;
                e.funcs["print:,*:"] = print;
 
                e.funcs["println:"] = println;
                e.funcs["println:,:"] = println;
                e.funcs["println:,*:"] = println;
            }
        }
    };
 
 
 
}