100 lines
2.6 KiB
C++
100 lines
2.6 KiB
C++
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/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include "kernel/replace.h"
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#include "kernel/metavar.h"
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#include "library/substitution.h"
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#include "library/kernel_bindings.h"
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namespace lean {
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expr find(substitution & s, expr e) {
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while (true) {
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if (is_metavar(e)) {
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expr * it = s.splay_find(metavar_name(e));
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if (it == nullptr)
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return e;
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e = *it;
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} else {
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return e;
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}
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}
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}
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expr apply(substitution & s, expr const & e) {
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auto f = [&](expr const & e, unsigned) -> expr {
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if (is_metavar(e)) {
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expr r = find(s, e);
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if (r != e) {
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if (has_metavar(r)) {
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r = apply(s, r);
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s.insert(metavar_name(e), r);
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}
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return apply_local_context(r, metavar_lctx(e));
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} else {
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return e;
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}
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} else {
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return e;
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}
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};
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return replace_fn<decltype(f)>(f)(e);
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}
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DECL_UDATA(substitution)
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static int substitution_size(lua_State * L) {
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lua_pushinteger(L, to_substitution(L, 1).size());
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return 1;
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}
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static int substitution_empty(lua_State * L) {
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lua_pushboolean(L, to_substitution(L, 1).empty());
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return 1;
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}
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static int substitution_find(lua_State * L) {
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substitution & s = to_substitution(L, 1);
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expr * it;
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if (is_expr(L, 2)) {
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expr const & e = to_expr(L, 2);
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if (is_metavar(e))
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it = s.splay_find(metavar_name(e));
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else
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throw exception("arg #2 must be a metavariable");
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} else {
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it = s.splay_find(to_name_ext(L, 2));
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}
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if (it)
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push_expr(L, find(s, *it));
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else
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lua_pushnil(L);
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return 1;
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}
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static int substitution_apply(lua_State * L) {
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return push_expr(L, apply(to_substitution(L, 1), to_expr(L, 2)));
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}
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static const struct luaL_Reg substitution_m[] = {
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{"__gc", substitution_gc}, // never throws
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{"__len", safe_function<substitution_size>},
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{"find", safe_function<substitution_find>},
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{"empty", safe_function<substitution_empty>},
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{"size", safe_function<substitution_size>},
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{"apply", safe_function<substitution_apply>},
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{0, 0}
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};
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void open_substitution(lua_State * L) {
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luaL_newmetatable(L, substitution_mt);
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lua_pushvalue(L, -1);
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lua_setfield(L, -2, "__index");
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setfuncs(L, substitution_m, 0);
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SET_GLOBAL_FUN(substitution_pred, "is_substitution");
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}
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}
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