Implement new magic frontend using sexpr

1 files changed, 1245 insertions, 0 deletions

diff --git a/src/map/magic-v2.cpp b/src/map/magic-v2.cpp
new file mode 100644
index 0000000..b10df3f
--- /dev/null
+++ b/src/map/magic-v2.cpp
@@ -0,0 +1,1245 @@
+#include "magic-v2.hpp"
+//    magic-v2.cpp - second generation magic parser
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    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 of the License, 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, see <http://www.gnu.org/licenses/>.
+
+#include <set>
+
+#include "../sexpr/parser.hpp"
+
+#include "../mmo/dumb_ptr.hpp"
+
+#include "itemdb.hpp"
+#include "magic-expr.hpp"
+
+#include "../poison.hpp"
+
+namespace magic_v2
+{
+    static
+    std::map<RString, proc_t> procs;
+    static
+    std::map<RString, val_t> const_defm;
+
+    static
+    size_t intern_id(ZString id_name)
+    {
+        // TODO use InternPool
+        size_t i;
+        for (i = 0; i < magic_conf.varv.size(); i++)
+            if (id_name == magic_conf.varv[i].name)
+                return i;
+
+        // i = magic_conf.varv.size();
+        /* Must add new */
+        magic_conf_t::mcvar new_var {};
+        new_var.name = id_name;
+        new_var.val.ty = TYPE::UNDEF;
+        magic_conf.varv.push_back(new_var);
+
+        return i;
+    }
+    inline
+    bool INTERN_ASSERT(ZString name, int id)
+    {
+        int zid = intern_id(name);
+        if (zid != id)
+        {
+            FPRINTF(stderr,
+                "[magic-conf] INTERNAL ERROR: Builtin special var %s interned to %d, not %d as it should be!\n",
+                name, zid, id);
+        }
+        return zid == id;
+    }
+
+    static
+    bool init0()
+    {
+        bool ok = true;
+
+        ok &= INTERN_ASSERT("min_casttime", VAR_MIN_CASTTIME);
+        ok &= INTERN_ASSERT("obscure_chance", VAR_OBSCURE_CHANCE);
+        ok &= INTERN_ASSERT("caster", VAR_CASTER);
+        ok &= INTERN_ASSERT("spellpower", VAR_SPELLPOWER);
+        ok &= INTERN_ASSERT("self_spell", VAR_SPELL);
+        ok &= INTERN_ASSERT("self_invocation", VAR_INVOCATION);
+        ok &= INTERN_ASSERT("target", VAR_TARGET);
+        ok &= INTERN_ASSERT("script_target", VAR_SCRIPTTARGET);
+        ok &= INTERN_ASSERT("location", VAR_LOCATION);
+
+        return ok;
+    }
+
+
+    static
+    bool bind_constant(io::LineSpan span, RString name, val_t *val)
+    {
+        if (!const_defm.insert({name, *val}).second)
+        {
+            span.error(STRPRINTF("Redefinition of constant '%s'", name));
+            return false;
+        }
+        return true;
+    }
+    static
+    val_t *find_constant(RString name)
+    {
+        auto it = const_defm.find(name);
+        if (it != const_defm.end())
+            return &it->second;
+
+        return NULL;
+    }
+    static
+    dumb_ptr<effect_t> new_effect(EFFECT ty)
+    {
+        auto effect = dumb_ptr<effect_t>::make();
+        effect->ty = ty;
+        return effect;
+    }
+    static
+    dumb_ptr<effect_t> set_effect_continuation(dumb_ptr<effect_t> src, dumb_ptr<effect_t> continuation)
+    {
+        dumb_ptr<effect_t> retval = src;
+        /* This function is completely analogous to `spellguard_implication' above; read the control flow implications above first before pondering it. */
+
+        if (src == continuation)
+            return retval;
+
+        /* For FOR and FOREACH, we use special stack handlers and thus don't have to set
+         * the continuation.  It's only IF that we need to handle in this fashion. */
+        if (src->ty == EFFECT::IF)
+        {
+            set_effect_continuation(src->e.e_if.true_branch, continuation);
+            set_effect_continuation(src->e.e_if.false_branch, continuation);
+        }
+
+        if (src->next)
+            set_effect_continuation(src->next, continuation);
+        else
+            src->next = continuation;
+
+        return retval;
+    }
+    static
+    dumb_ptr<spellguard_t> new_spellguard(SPELLGUARD ty)
+    {
+        dumb_ptr<spellguard_t> retval = dumb_ptr<spellguard_t>::make();
+        retval->ty = ty;
+        return retval;
+    }
+    static
+    dumb_ptr<spellguard_t> spellguard_implication(dumb_ptr<spellguard_t> a, dumb_ptr<spellguard_t> b)
+    {
+        dumb_ptr<spellguard_t> retval = a;
+
+        if (a == b)
+        {
+            /* This can happen due to reference sharing:
+             * e.g.,
+             *  (R0 -> (R1 | R2)) => (R3)
+             * yields
+             *  (R0 -> (R1 -> R3 | R2 -> R3))
+             *
+             * So if we now add => R4 to that, we want
+             *  (R0 -> (R1 -> R3 -> R4 | R2 -> R3 -> R4))
+             *
+             * but we only need to add it once, because the R3 reference is shared.
+             */
+            return retval;
+        }
+
+        /* If the premise is a disjunction, b is the continuation of _all_ branches */
+        if (a->ty == SPELLGUARD::CHOICE)
+            spellguard_implication(a->s.s_alt, b);
+
+        if (a->next)
+            spellguard_implication(a->next, b);
+        else
+            // this is the important bit
+            a->next = b;
+
+        return retval;
+    }
+
+
+    static
+    bool add_spell(io::LineSpan span, dumb_ptr<spell_t> spell)
+    {
+        auto pair1 = magic_conf.spells_by_name.insert({spell->name, spell});
+        if (!pair1.second)
+        {
+            span.error(STRPRINTF("Attempt to redefine spell '%s'", spell->name));
+            return false;
+        }
+
+        auto pair2 = magic_conf.spells_by_invocation.insert({spell->invocation, spell});
+        if (!pair2.second)
+        {
+            span.error(STRPRINTF("Attempt to redefine spell invocation '%s'", spell->invocation));
+            magic_conf.spells_by_name.erase(pair1.first);
+            return false;
+        }
+        return true;
+    }
+    static
+    bool add_teleport_anchor(io::LineSpan span, dumb_ptr<teleport_anchor_t> anchor)
+    {
+        auto pair1 = magic_conf.anchors_by_name.insert({anchor->name, anchor});
+        if (!pair1.second)
+        {
+            span.error(STRPRINTF("Attempt to redefine teleport anchor '%s'", anchor->name));
+            return false;
+        }
+
+        auto pair2 = magic_conf.anchors_by_invocation.insert({anchor->name, anchor});
+        if (!pair2.second)
+        {
+            span.error(STRPRINTF("Attempt to redefine anchor invocation '%s'", anchor->invocation));
+            magic_conf.anchors_by_name.erase(pair1.first);
+            return false;
+        }
+        return true;
+    }
+
+    static
+    bool install_proc(io::LineSpan span, dumb_ptr<proc_t> proc)
+    {
+        RString name = proc->name;
+        if (!procs.insert({name, std::move(*proc)}).second)
+        {
+            span.error("procedure already exists");
+            return false;
+        }
+        return true;
+    }
+    static
+    bool call_proc(io::LineSpan span, ZString name, dumb_ptr<std::vector<dumb_ptr<expr_t>>> argvp, dumb_ptr<effect_t>& retval)
+    {
+        auto pi = procs.find(name);
+        if (pi == procs.end())
+        {
+            span.error(STRPRINTF("Unknown procedure '%s'", name));
+            return false;
+        }
+
+        proc_t *p = &pi->second;
+
+        if (p->argv.size() != argvp->size())
+        {
+            span.error(STRPRINTF("Procedure %s/%zu invoked with %zu parameters",
+                        name, p->argv.size(), argvp->size()));
+            return false;
+        }
+
+        retval = new_effect(EFFECT::CALL);
+        retval->e.e_call.body = p->body;
+        retval->e.e_call.formalv = &p->argv;
+        retval->e.e_call.actualvp = argvp;
+        return true;
+    }
+    static
+    bool op_effect(io::LineSpan span, ZString name, const_array<dumb_ptr<expr_t>> argv, dumb_ptr<effect_t>& effect)
+    {
+        op_t *op = magic_get_op(name);
+        if (!op)
+        {
+            span.error(STRPRINTF("Unknown operation '%s'", name));
+            return false;
+        }
+        if (op->signature.size() != argv.size())
+        {
+            span.error(STRPRINTF("Incorrect number of arguments to operation '%s': Expected %zu, found %zu",
+                    name, op->signature.size(), argv.size()));
+            return false;
+        }
+
+        effect = new_effect(EFFECT::OP);
+        effect->e.e_op.line_nr = span.begin.line;
+        effect->e.e_op.column = span.begin.column;
+        effect->e.e_op.opp = op;
+        assert (argv.size() <= MAX_ARGS);
+        effect->e.e_op.args_nr = argv.size();
+
+        std::copy(argv.begin(), argv.end(), effect->e.e_op.args);
+        return true;
+    }
+
+    static
+    dumb_ptr<expr_t> dot_expr(dumb_ptr<expr_t> expr, int id)
+    {
+        dumb_ptr<expr_t> retval = magic_new_expr(EXPR::SPELLFIELD);
+        retval->e.e_field.id = id;
+        retval->e.e_field.expr = expr;
+
+        return retval;
+    }
+    static
+    bool fun_expr(io::LineSpan span, ZString name, const_array<dumb_ptr<expr_t>> argv, dumb_ptr<expr_t>& expr)
+    {
+        fun_t *fun = magic_get_fun(name);
+        if (!fun)
+        {
+            span.error(STRPRINTF("Unknown function '%s'", name));
+            return false;
+        }
+        if (fun->signature.size() != argv.size())
+        {
+            span.error(STRPRINTF("Incorrect number of arguments to function '%s': Expected %zu, found %zu",
+                    name, fun->signature.size(), argv.size()));
+            return false;
+        }
+        expr = magic_new_expr(EXPR::FUNAPP);
+        expr->e.e_funapp.line_nr = span.begin.line;
+        expr->e.e_funapp.column = span.begin.column;
+        expr->e.e_funapp.funp = fun;
+
+        assert (argv.size() <= MAX_ARGS);
+        expr->e.e_funapp.args_nr = argv.size();
+
+        std::copy(argv.begin(), argv.end(), expr->e.e_funapp.args);
+        return true;
+    }
+    static
+    dumb_ptr<expr_t> BIN_EXPR(io::LineSpan span, ZString name, dumb_ptr<expr_t> left, dumb_ptr<expr_t> right)
+    {
+        dumb_ptr<expr_t> e[2];
+        e[0] = left;
+        e[1] = right;
+        dumb_ptr<expr_t> rv;
+        if (!fun_expr(span, name, const_array<dumb_ptr<expr_t>>(e, 2), rv))
+            abort();
+        return rv;
+    }
+
+    static
+    bool fail(const sexpr::SExpr& s, ZString msg)
+    {
+        s._span.error(msg);
+        return false;
+    }
+}
+
+namespace magic_v2
+{
+    using sexpr::SExpr;
+
+    static
+    bool parse_expression(const SExpr& x, dumb_ptr<expr_t>& out);
+    static
+    bool parse_effect(const SExpr& s, dumb_ptr<effect_t>& out);
+    static
+    bool parse_spellguard(const SExpr& s, dumb_ptr<spellguard_t>& out);
+    static
+    bool parse_spellbody(const SExpr& s, dumb_ptr<spellguard_t>& out);
+
+    // Note: anything with dumb_ptr leaks memory on failure
+    // once this is all done, we can convert it to unique_ptr
+    // (may require bimaps somewhere)
+    static
+    bool is_comment(const SExpr& s)
+    {
+        if (s._type == sexpr::STRING)
+            return true;
+        if (s._type != sexpr::LIST)
+            return false;
+        if (s._list.empty())
+            return false;
+        if (s._list[0]._type != sexpr::TOKEN)
+            return false;
+        return s._list[0]._str == "DISABLED";
+    }
+
+    static
+    bool parse_loc(const SExpr& s, e_location_t& loc)
+    {
+        if (s._type != sexpr::LIST)
+            return fail(s, "loc not list");
+        if (s._list.size() != 4)
+            return fail(s, "loc not 3 args");
+        if (s._list[0]._type != sexpr::TOKEN)
+            return fail(s._list[0], "loc cmd not tok");
+        if (s._list[0]._str != "@")
+            return fail(s._list[0], "loc cmd not cmd");
+        return parse_expression(s._list[1], loc.m)
+            && parse_expression(s._list[2], loc.x)
+            && parse_expression(s._list[3], loc.y);
+    }
+
+    static
+    bool parse_expression(const SExpr& x, dumb_ptr<expr_t>& out)
+    {
+        switch (x._type)
+        {
+        case sexpr::INT:
+            {
+                val_t val;
+                val.ty = TYPE::INT;
+                val.v.v_int = x._int;
+                if (val.v.v_int != x._int)
+                    return fail(x, "integer too large");
+
+                out = magic_new_expr(EXPR::VAL);
+                out->e.e_val = val;
+                return true;
+            }
+        case sexpr::STRING:
+            {
+                val_t val;
+                val.ty = TYPE::STRING;
+                val.v.v_string = dumb_string::copys(x._str);
+
+                out = magic_new_expr(EXPR::VAL);
+                out->e.e_val = val;
+                return true;
+            }
+        case sexpr::TOKEN:
+            {
+                ZString dirs[8] = {
+                    "S", "SW", "W", "NW", "N", "NE", "E", "SE",
+                };
+                auto begin = std::begin(dirs);
+                auto end = std::end(dirs);
+                auto it = std::find(begin, end, x._str);
+                if (it != end)
+                {
+                    val_t val;
+                    val.ty = TYPE::DIR;
+                    val.v.v_dir = static_cast<DIR>(it - begin);
+
+                    out = magic_new_expr(EXPR::VAL);
+                    out->e.e_val = val;
+                    return true;
+                }
+            }
+            {
+                if (val_t *val = find_constant(x._str))
+                {
+                    out = magic_new_expr(EXPR::VAL);
+                    out->e.e_val = *val;
+                    return true;
+                }
+                else
+                {
+                    out = magic_new_expr(EXPR::ID);
+                    out->e.e_id = intern_id(x._str);
+                    return true;
+                }
+            }
+            break;
+        case sexpr::LIST:
+            if (x._list.empty())
+                return fail(x, "empty list");
+            {
+                if (x._list[0]._type != sexpr::TOKEN)
+                    return fail(x._list[0], "op not token");
+                ZString op = x._list[0]._str;
+                // area
+                if (op == "@")
+                {
+                    e_location_t loc;
+                    if (!parse_loc(x, loc))
+                        return false;
+                    out = magic_new_expr(EXPR::AREA);
+                    out->e.e_area.ty = AREA::LOCATION;
+                    out->e.e_area.a.a_loc = loc;
+                    return true;
+                }
+                if (op == "@+")
+                {
+                    e_location_t loc;
+                    dumb_ptr<expr_t> width;
+                    dumb_ptr<expr_t> height;
+                    if (!parse_loc(x._list[1], loc))
+                        return false;
+                    if (!parse_expression(x._list[2], width))
+                        return false;
+                    if (!parse_expression(x._list[3], height))
+                        return false;
+                    out = magic_new_expr(EXPR::AREA);
+                    out->e.e_area.ty = AREA::RECT;
+                    out->e.e_area.a.a_rect.loc = loc;
+                    out->e.e_area.a.a_rect.width = width;
+                    out->e.e_area.a.a_rect.height = height;
+                    return true;
+                }
+                if (op == "TOWARDS")
+                {
+                    e_location_t loc;
+                    dumb_ptr<expr_t> dir;
+                    dumb_ptr<expr_t> width;
+                    dumb_ptr<expr_t> depth;
+                    if (!parse_loc(x._list[1], loc))
+                        return false;
+                    if (!parse_expression(x._list[2], dir))
+                        return false;
+                    if (!parse_expression(x._list[3], width))
+                        return false;
+                    if (!parse_expression(x._list[4], depth))
+                        return false;
+                    out = magic_new_expr(EXPR::AREA);
+                    out->e.e_area.ty = AREA::BAR;
+                    out->e.e_area.a.a_bar.loc = loc;
+                    out->e.e_area.a.a_bar.dir = dir;
+                    out->e.e_area.a.a_bar.width = width;
+                    out->e.e_area.a.a_bar.depth = depth;
+                    return true;
+                }
+                if (op == ".")
+                {
+                    if (x._list.size() != 3)
+                        return fail(x, ". not 2");
+                    dumb_ptr<expr_t> expr;
+                    if (!parse_expression(x._list[1], expr))
+                        return false;
+                    if (x._list[2]._type != sexpr::TOKEN)
+                        return fail(x._list[2], ".elem not name");
+                    ZString elem = x._list[2]._str;
+                    out = dot_expr(expr, intern_id(elem));
+                    return true;
+                }
+                static
+                std::set<ZString> ops =
+                {
+                    "<", ">", "<=", ">=", "==", "!=",
+                    "+", "-", "*", "%", "/",
+                    "&", "^", "|", "<<", ">>",
+                    "&&", "||",
+                };
+                // TODO implement unary operators
+                if (ops.count(op))
+                {
+                    // operators are n-ary and left-associative
+                    if (x._list.size() < 3)
+                        return fail(x, "operator not at least 2 args");
+                    auto begin = x._list.begin() + 1;
+                    auto end = x._list.end();
+                    if (!parse_expression(*begin, out))
+                        return false;
+                    ++begin;
+                    for (; begin != end; ++begin)
+                    {
+                        dumb_ptr<expr_t> tmp;
+                        if (!parse_expression(*begin, tmp))
+                            return false;
+                        out = BIN_EXPR(x._span, op, out, tmp);
+                    }
+                    return true;
+                }
+                std::vector<dumb_ptr<expr_t>> argv;
+                for (auto it = x._list.begin() + 1, end = x._list.end(); it != end; ++it)
+                {
+                    dumb_ptr<expr_t> expr;
+                    if (!parse_expression(*it, expr))
+                        return false;
+                    argv.push_back(expr);
+                }
+                return fun_expr(x._span, op, argv, out);
+            }
+            break;
+        }
+        abort();
+    }
+
+    static
+    bool parse_item(const SExpr& s, int& id, int& count)
+    {
+        if (s._type == sexpr::STRING)
+        {
+            count = 1;
+
+            item_data *item = itemdb_searchname(s._str);
+            if (!item)
+                return fail(s, "no such item");
+            id = item->nameid;
+            return true;
+        }
+        if (s._type != sexpr::LIST)
+            return fail(s, "item not string or list");
+        if (s._list.size() != 2)
+            return fail(s, "item list is not pair");
+        if (s._list[0]._type != sexpr::INT)
+            return fail(s._list[0], "item pair first not int");
+        count = s._list[0]._int;
+        if (s._list[1]._type != sexpr::STRING)
+            return fail(s._list[1], "item pair second not name");
+
+        item_data *item = itemdb_searchname(s._list[1]._str);
+        if (!item)
+            return fail(s, "no such item");
+        id = item->nameid;
+        return true;
+    }
+
+    static
+    bool parse_spellguard(const SExpr& s, dumb_ptr<spellguard_t>& out)
+    {
+        if (s._type != sexpr::LIST)
+            return fail(s, "not list");
+        if (s._list.empty())
+            return fail(s, "empty list");
+        if (s._list[0]._type != sexpr::TOKEN)
+            return fail(s._list[0], "not token");
+        ZString cmd = s._list[0]._str;
+        if (cmd == "OR")
+        {
+            auto begin = s._list.begin() + 1;
+            auto end = s._list.end();
+            if (begin == end)
+                return fail(s, "missing arguments");
+            if (!parse_spellguard(*begin, out))
+                return false;
+            ++begin;
+            for (; begin != end; ++begin)
+            {
+                dumb_ptr<spellguard_t> alt;
+                if (!parse_spellguard(*begin, alt))
+                    return false;
+                dumb_ptr<spellguard_t> choice = new_spellguard(SPELLGUARD::CHOICE);
+                choice->next = out;
+                choice->s.s_alt = alt;
+                out = choice;
+            }
+            return true;
+        }
+        if (cmd == "GUARD")
+        {
+            auto begin = s._list.begin() + 1;
+            auto end = s._list.end();
+            while (is_comment(end[-1]))
+                --end;
+            if (begin == end)
+                return fail(s, "missing arguments");
+            if (!parse_spellguard(end[-1], out))
+                return false;
+            --end;
+            for (; begin != end; --end)
+            {
+                if (is_comment(end[-1]))
+                    continue;
+                dumb_ptr<spellguard_t> implier;
+                if (!parse_spellguard(end[-1], implier))
+                    return false;
+                out = spellguard_implication(implier, out);
+            }
+            return true;
+        }
+        if (cmd == "REQUIRE")
+        {
+            if (s._list.size() != 2)
+                return fail(s, "not one argument");
+            dumb_ptr<expr_t> condition;
+            if (!parse_expression(s._list[1], condition))
+                return false;
+            out = new_spellguard(SPELLGUARD::CONDITION);
+            out->s.s_condition = condition;
+            return true;
+        }
+        if (cmd == "MANA")
+        {
+            if (s._list.size() != 2)
+                return fail(s, "not one argument");
+            dumb_ptr<expr_t> mana;
+            if (!parse_expression(s._list[1], mana))
+                return false;
+            out = new_spellguard(SPELLGUARD::MANA);
+            out->s.s_mana = mana;
+            return true;
+        }
+        if (cmd == "CASTTIME")
+        {
+            if (s._list.size() != 2)
+                return fail(s, "not one argument");
+            dumb_ptr<expr_t> casttime;
+            if (!parse_expression(s._list[1], casttime))
+                return false;
+            out = new_spellguard(SPELLGUARD::CASTTIME);
+            out->s.s_casttime = casttime;
+            return true;
+        }
+        if (cmd == "CATALYSTS")
+        {
+            dumb_ptr<component_t> items = nullptr;
+            for (auto it = s._list.begin() + 1, end = s._list.end(); it != end; ++it)
+            {
+                int id, count;
+                if (!parse_item(*it, id, count))
+                    return false;
+                magic_add_component(&items, id, count);
+            }
+            out = new_spellguard(SPELLGUARD::CATALYSTS);
+            out->s.s_catalysts = items;
+            return true;
+        }
+        if (cmd == "COMPONENTS")
+        {
+            dumb_ptr<component_t> items = nullptr;
+            for (auto it = s._list.begin() + 1, end = s._list.end(); it != end; ++it)
+            {
+                int id, count;
+                if (!parse_item(*it, id, count))
+                    return false;
+                magic_add_component(&items, id, count);
+            }
+            out = new_spellguard(SPELLGUARD::COMPONENTS);
+            out->s.s_components = items;
+            return true;
+        }
+        return fail(s._list[0], "unknown guard");
+    }
+
+    static
+    bool build_effect_list(std::vector<SExpr>::const_iterator begin,
+            std::vector<SExpr>::const_iterator end, dumb_ptr<effect_t>& out)
+    {
+        // these backward lists could be forward by keeping the reference
+        // I know this is true because Linus said so
+        out = new_effect(EFFECT::SKIP);
+        while (end != begin)
+        {
+            const SExpr& s = *--end;
+            if (is_comment(s))
+                continue;
+            dumb_ptr<effect_t> chain;
+            if (!parse_effect(s, chain))
+                return false;
+            out = set_effect_continuation(chain, out);
+        }
+        return true;
+    }
+
+    static
+    bool parse_effect(const SExpr& s, dumb_ptr<effect_t>& out)
+    {
+        if (s._type != sexpr::LIST)
+            return fail(s, "not list");
+        if (s._list.empty())
+            return fail(s, "empty list");
+        if (s._list[0]._type != sexpr::TOKEN)
+            return fail(s._list[0], "not token");
+        ZString cmd = s._list[0]._str;
+        if (cmd == "BLOCK")
+        {
+            return build_effect_list(s._list.begin() + 1, s._list.end(), out);
+        }
+        if (cmd == "SET")
+        {
+            if (s._list.size() != 3)
+                return fail(s, "not 2 args");
+            if (s._list[1]._type != sexpr::TOKEN)
+                return fail(s._list[1], "not token");
+            ZString name = s._list[1]._str;
+            if (find_constant(name))
+                return fail(s._list[1], "assigning to constant");
+            dumb_ptr<expr_t> expr;
+            if (!parse_expression(s._list[2], expr))
+                return false;
+
+            out = new_effect(EFFECT::ASSIGN);
+            out->e.e_assign.id = intern_id(name);
+            out->e.e_assign.expr = expr;
+            return true;
+        }
+        if (cmd == "SCRIPT")
+        {
+            if (s._list.size() != 2)
+                return fail(s, "not 1 arg");
+            if (s._list[1]._type != sexpr::STRING)
+                return fail(s._list[1], "not string");
+            ZString body = s._list[1]._str;
+            std::unique_ptr<const ScriptBuffer> script = parse_script(body, s._list[1]._span.begin.line);
+            if (!script)
+                return fail(s._list[1], "script does not compile");
+            out = new_effect(EFFECT::SCRIPT);
+            out->e.e_script = dumb_ptr<const ScriptBuffer>(script.release());
+            return true;
+        }
+        if (cmd == "SKIP")
+        {
+            if (s._list.size() != 1)
+                return fail(s, "not 0 arg");
+            out = new_effect(EFFECT::SKIP);
+            return true;
+        }
+        if (cmd == "ABORT")
+        {
+            if (s._list.size() != 1)
+                return fail(s, "not 0 arg");
+            out = new_effect(EFFECT::ABORT);
+            return true;
+        }
+        if (cmd == "END")
+        {
+            if (s._list.size() != 1)
+                return fail(s, "not 0 arg");
+            out = new_effect(EFFECT::END);
+            return true;
+        }
+        if (cmd == "BREAK")
+        {
+            if (s._list.size() != 1)
+                return fail(s, "not 0 arg");
+            out = new_effect(EFFECT::BREAK);
+            return true;
+        }
+        if (cmd == "FOREACH")
+        {
+            if (s._list.size() != 5)
+                return fail(s, "not 4 arg");
+            if (s._list[1]._type != sexpr::TOKEN)
+                return fail(s._list[1], "foreach type not token");
+            ZString type = s._list[1]._str;
+            FOREACH_FILTER filter;
+            if (type == "PC")
+                filter = FOREACH_FILTER::PC;
+            else if (type == "MOB")
+                filter = FOREACH_FILTER::MOB;
+            else if (type == "ENTITY")
+                filter = FOREACH_FILTER::ENTITY;
+            else if (type == "SPELL")
+                filter = FOREACH_FILTER::SPELL;
+            else if (type == "TARGET")
+                filter = FOREACH_FILTER::TARGET;
+            else if (type == "NPC")
+                filter = FOREACH_FILTER::NPC;
+            else
+                return fail(s._list[1], "unknown foreach filter");
+            if (s._list[2]._type != sexpr::TOKEN)
+                return fail(s._list[2], "foreach var not token");
+            ZString var = s._list[2]._str;
+            dumb_ptr<expr_t> area;
+            dumb_ptr<effect_t> effect;
+            if (!parse_expression(s._list[3], area))
+                return false;
+            if (!parse_effect(s._list[4], effect))
+                return false;
+            out = new_effect(EFFECT::FOREACH);
+            out->e.e_foreach.id = intern_id(var);
+            out->e.e_foreach.area = area;
+            out->e.e_foreach.body = effect;
+            out->e.e_foreach.filter = filter;
+            return true;
+        }
+        if (cmd == "FOR")
+        {
+            if (s._list.size() != 5)
+                return fail(s, "not 4 arg");
+            if (s._list[1]._type != sexpr::TOKEN)
+                return fail(s._list[1], "for var not token");
+            ZString var = s._list[1]._str;
+            dumb_ptr<expr_t> low;
+            dumb_ptr<expr_t> high;
+            dumb_ptr<effect_t> effect;
+            if (!parse_expression(s._list[2], low))
+                return false;
+            if (!parse_expression(s._list[3], high))
+                return false;
+            if (!parse_effect(s._list[4], effect))
+                return false;
+            out = new_effect(EFFECT::FOR);
+            out->e.e_for.id = intern_id(var);
+            out->e.e_for.start = low;
+            out->e.e_for.stop = high;
+            out->e.e_for.body = effect;
+            return true;
+        }
+        if (cmd == "IF")
+        {
+            if (s._list.size() != 3 && s._list.size() != 4)
+                return fail(s, "not 2 or 3 args");
+            dumb_ptr<expr_t> cond;
+            dumb_ptr<effect_t> if_true;
+            dumb_ptr<effect_t> if_false;
+            if (!parse_expression(s._list[1], cond))
+                return false;
+            if (!parse_effect(s._list[2], if_true))
+                return false;
+            if (s._list.size() == 4)
+            {
+                if (!parse_effect(s._list[3], if_false))
+                    return false;
+            }
+            else
+                if_false = new_effect(EFFECT::SKIP);
+            out = new_effect(EFFECT::IF);
+            out->e.e_if.cond = cond;
+            out->e.e_if.true_branch = if_true;
+            out->e.e_if.false_branch = if_false;
+            return true;
+        }
+        if (cmd == "WAIT")
+        {
+            if (s._list.size() != 2)
+                return fail(s, "not 1 arg");
+            dumb_ptr<expr_t> expr;
+            if (!parse_expression(s._list[1], expr))
+                return false;
+            out = new_effect(EFFECT::SLEEP);
+            out->e.e_sleep = expr;
+            return true;
+        }
+        if (cmd == "CALL")
+        {
+            if (s._list.size() < 2)
+                return fail(s, "call what?");
+            if (s._list[1]._type != sexpr::TOKEN)
+                return fail(s._list[1], "call token please");
+            ZString func = s._list[1]._str;
+            auto argvp = dumb_ptr<std::vector<dumb_ptr<expr_t>>>::make();
+            for (auto it = s._list.begin() + 2, end = s._list.end(); it != end; ++it)
+            {
+                dumb_ptr<expr_t> expr;
+                if (!parse_expression(*it, expr))
+                    return false;
+                argvp->push_back(expr);
+            }
+            return call_proc(s._span, func, argvp, out);
+        }
+        auto argv = std::vector<dumb_ptr<expr_t>>();
+        for (auto it = s._list.begin() + 1, end = s._list.end(); it != end; ++it)
+        {
+            dumb_ptr<expr_t> expr;
+            if (!parse_expression(*it, expr))
+                return false;
+            argv.push_back(expr);
+        }
+        return op_effect(s._span, cmd, argv, out);
+    }
+
+    static
+    bool parse_spellbody(const SExpr& s, dumb_ptr<spellguard_t>& out)
+    {
+        if (s._type != sexpr::LIST)
+            return fail(s, "not list");
+        if (s._list.empty())
+            return fail(s, "empty list");
+        if (s._list[0]._type != sexpr::TOKEN)
+            return fail(s._list[0], "not token");
+        ZString cmd = s._list[0]._str;
+        if (cmd == "=>")
+        {
+            if (s._list.size() != 3)
+                return fail(s, "list does not have exactly 2 arguments");
+            dumb_ptr<spellguard_t> guard;
+            if (!parse_spellguard(s._list[1], guard))
+                return false;
+            dumb_ptr<spellguard_t> body;
+            if (!parse_spellbody(s._list[2], body))
+                return false;
+            out = spellguard_implication(guard, body);
+            return true;
+        }
+        if (cmd == "|")
+        {
+            if (s._list.size() == 1)
+                return fail(s, "spellbody choice empty");
+            auto begin = s._list.begin() + 1;
+            auto end = s._list.end();
+            if (!parse_spellbody(*begin, out))
+                return false;
+            ++begin;
+            for (; begin != end; ++begin)
+            {
+                dumb_ptr<spellguard_t> alt;
+                if (!parse_spellbody(*begin, alt))
+                    return false;
+                auto tmp = out;
+                out = new_spellguard(SPELLGUARD::CHOICE);
+                out->next = tmp;
+                out->s.s_alt = alt;
+            }
+            return true;
+        }
+        if (cmd == "EFFECT")
+        {
+            auto begin = s._list.begin() + 1;
+            auto end = s._list.end();
+
+            dumb_ptr<effect_t> effect, attrig, atend;
+
+            // decreasing end can never pass begin, since we know that
+            // begin[-1] is token EFFECT
+            while (is_comment(end[-1]))
+                --end;
+            if (end[-1]._type == sexpr::LIST && !end[-1]._list.empty()
+                    && end[-1]._list[0]._type == sexpr::TOKEN
+                    && end[-1]._list[0]._str == "ATEND")
+            {
+                auto atb = end[-1]._list.begin() + 1;
+                auto ate = end[-1]._list.end();
+                if (!build_effect_list(atb, ate, atend))
+                    return false;
+                --end;
+
+                while (is_comment(end[-1]))
+                    --end;
+            }
+            else
+            {
+                atend = nullptr;
+            }
+            if (end[-1]._type == sexpr::LIST && !end[-1]._list.empty()
+                    && end[-1]._list[0]._type == sexpr::TOKEN
+                    && end[-1]._list[0]._str == "ATTRIGGER")
+            {
+                auto atb = end[-1]._list.begin() + 1;
+                auto ate = end[-1]._list.end();
+                if (!build_effect_list(atb, ate, attrig))
+                    return false;
+                --end;
+            }
+            else
+            {
+                attrig = nullptr;
+            }
+            if (!build_effect_list(begin, end, effect))
+                return false;
+            out = new_spellguard(SPELLGUARD::EFFECT);
+            out->s.s_effect.effect = effect;
+            out->s.s_effect.at_trigger = attrig;
+            out->s.s_effect.at_end = atend;
+            return true;
+        }
+        return fail(s._list[0], "unknown spellbody");
+    }
+
+    static
+    bool parse_top_set(const std::vector<SExpr>& in)
+    {
+        if (in.size() != 3)
+            return fail(in[0], "not 2 arguments");
+        ZString name = in[1]._str;
+        dumb_ptr<expr_t> expr;
+        if (!parse_expression(in[2], expr))
+            return false;
+        if (find_constant(name))
+            return fail(in[1], "assign constant");
+        size_t var_id = intern_id(name);
+        magic_eval(dumb_ptr<env_t>(&magic_default_env), &magic_conf.varv[var_id].val, expr);
+        return true;
+    }
+    static
+    bool parse_const(io::LineSpan span, const std::vector<SExpr>& in)
+    {
+        if (in.size() != 3)
+            return fail(in[0], "not 2 arguments");
+        if (in[1]._type != sexpr::TOKEN)
+            return fail(in[1], "not token");
+        ZString name = in[1]._str;
+        dumb_ptr<expr_t> expr;
+        if (!parse_expression(in[2], expr))
+            return false;
+        val_t tmp;
+        magic_eval(dumb_ptr<env_t>(&magic_default_env), &tmp, expr);
+        return bind_constant(span, name, &tmp);
+    }
+    static
+    bool parse_anchor(io::LineSpan span, const std::vector<SExpr>& in)
+    {
+        if (in.size() != 4)
+            return fail(in[0], "not 3 arguments");
+        auto anchor = dumb_ptr<teleport_anchor_t>::make();
+        if (in[1]._type != sexpr::TOKEN)
+            return fail(in[1], "not token");
+        anchor->name = in[1]._str;
+        if (in[2]._type != sexpr::STRING)
+            return fail(in[2], "not string");
+        anchor->invocation = in[2]._str;
+        dumb_ptr<expr_t> expr;
+        if (!parse_expression(in[3], expr))
+            return false;
+        anchor->location = expr;
+        return add_teleport_anchor(span, anchor);
+    }
+    static
+    bool parse_proc(io::LineSpan span, const std::vector<SExpr>& in)
+    {
+        if (in.size() < 4)
+            return fail(in[0], "not at least 3 arguments");
+        auto proc = dumb_ptr<proc_t>::make();
+        if (in[1]._type != sexpr::TOKEN)
+            return fail(in[1], "name not token");
+        proc->name = in[1]._str;
+        if (in[2]._type != sexpr::LIST)
+            return fail(in[2], "args not list");
+        for (const SExpr& arg : in[2]._list)
+        {
+            if (arg._type != sexpr::TOKEN)
+                return fail(arg, "arg not token");
+            proc->argv.push_back(intern_id(arg._str));
+        }
+        if (!build_effect_list(in.begin() + 3, in.end(), proc->body))
+            return false;
+        return install_proc(span, proc);
+    }
+    static
+    bool parse_spell(io::LineSpan span, const std::vector<SExpr>& in)
+    {
+        if (in.size() < 6)
+            return fail(in[0], "not at least 5 arguments");
+        if (in[1]._type != sexpr::LIST)
+            return fail(in[1], "flags not list");
+
+        auto spell = dumb_ptr<spell_t>::make();
+
+        for (const SExpr& s : in[1]._list)
+        {
+            if (s._type != sexpr::TOKEN)
+                return fail(s, "flag not token");
+            SPELL_FLAG flag = SPELL_FLAG::ZERO;
+            if (s._str == "LOCAL")
+                flag = SPELL_FLAG::LOCAL;
+            else if (s._str == "NONMAGIC")
+                flag = SPELL_FLAG::NONMAGIC;
+            else if (s._str == "SILENT")
+                flag = SPELL_FLAG::SILENT;
+            else
+                return fail(s, "unknown flag");
+            if (bool(spell->flags & flag))
+                return fail(s, "duplicate flag");
+            spell->flags |= flag;
+        }
+        if (in[2]._type != sexpr::TOKEN)
+            return fail(in[2], "name not token");
+        spell->name = in[2]._str;
+        if (in[3]._type != sexpr::STRING)
+            return fail(in[3], "invoc not string");
+        spell->invocation = in[3]._str;
+        if (in[4]._type != sexpr::LIST)
+            return fail(in[4], "spellarg not list");
+        if (in[4]._list.size() == 0)
+        {
+            spell->spellarg_ty = SPELLARG::NONE;
+        }
+        else
+        {
+            if (in[4]._list.size() != 2)
+                return fail(in[4], "spellarg not empty list or pair");
+            if (in[4]._list[0]._type != sexpr::TOKEN)
+                return fail(in[4]._list[0], "spellarg type not token");
+            if (in[4]._list[1]._type != sexpr::TOKEN)
+                return fail(in[4]._list[1], "spellarg name not token");
+            ZString ty = in[4]._list[0]._str;
+            if (ty == "PC")
+                spell->spellarg_ty = SPELLARG::PC;
+            else if (ty == "STRING")
+                spell->spellarg_ty = SPELLARG::STRING;
+            else
+                return fail(in[4]._list[0], "unknown spellarg type");
+            ZString an = in[4]._list[1]._str;
+            spell->arg = intern_id(an);
+        }
+        std::vector<SExpr>::const_iterator it = in.begin() + 5;
+        for (;; ++it)
+        {
+            if (it == in.end())
+                return fail(it[-1], "end of list scanning LET defs");
+            if (is_comment(*it))
+                continue;
+            if (it->_type != sexpr::LIST || it->_list.empty())
+                break;
+            if (it->_list[0]._type != sexpr::TOKEN || it->_list[0]._str != "LET")
+                break;
+
+            if (it->_list[1]._type != sexpr::TOKEN)
+                return fail(it->_list[1], "let name not token");
+            ZString name = it->_list[1]._str;
+            if (find_constant(name))
+                return fail(it->_list[1], "constant exists");
+            dumb_ptr<expr_t> expr;
+            if (!parse_expression(it->_list[2], expr))
+                return false;
+            letdef_t let;
+            let.id = intern_id(name);
+            let.expr = expr;
+            spell->letdefv.push_back(let);
+        }
+        if (it + 1 != in.end())
+            return fail(*it, "expected only one body entry besides LET");
+
+        // formally, 'guard' only refers to the first argument of '=>'
+        // but internally, spellbodies use the same thing
+        dumb_ptr<spellguard_t> guard;
+        if (!parse_spellbody(*it, guard))
+            return false;
+        spell->spellguard = guard;
+        return add_spell(span, spell);
+    }
+
+    static
+    bool parse_top(io::LineSpan span, const std::vector<SExpr>& vs)
+    {
+        if (vs.empty())
+        {
+            span.error("Empty list at top");
+            return false;
+        }
+        if (vs[0]._type != sexpr::TOKEN)
+            return fail(vs[0], "top not token");
+        ZString cmd = vs[0]._str;
+        if (cmd == "CONST")
+            return parse_const(span, vs);
+        if (cmd == "PROCEDURE")
+            return parse_proc(span, vs);
+        if (cmd == "SET")
+            return parse_top_set(vs);
+        if (cmd == "SPELL")
+            return parse_spell(span, vs);
+        if (cmd == "TELEPORT-ANCHOR")
+            return parse_anchor(span, vs);
+        return fail(vs[0], "Unknown top-level command");
+    }
+
+    static
+    bool loop(sexpr::Lexer& in)
+    {
+        SExpr s;
+        while (sexpr::parse(in, s))
+        {
+            if (is_comment(s))
+                continue;
+            if (s._type != sexpr::LIST)
+                return fail(s, "top-level entity not a list or comment");
+            if (!parse_top(s._span, s._list))
+                return false;
+        }
+        // handle low-level errors
+        if (in.peek() != sexpr::TOK_EOF)
+        {
+            in.span().error("parser gave up before end of file");
+            return false;
+        }
+        return true;
+    }
+} // namespace magic_v2
+
+bool magic_init0()
+{
+    return magic_v2::init0();
+}
+
+bool load_magic_file_v2(ZString filename)
+{
+    sexpr::Lexer in(filename);
+    bool rv = magic_v2::loop(in);
+    if (!rv)
+    {
+        in.span().error(STRPRINTF("next token: %s '%s'", sexpr::token_name(in.peek()), in.val_string()));
+    }
+    return rv;
+}