feat(lua): expose basic API for Lean expressions in the Lua bindings

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-11-07 21:53:57 -08:00
parent fb09fc9fe6
commit b57ad80d5e
5 changed files with 248 additions and 3 deletions

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@ -1,3 +1,4 @@
add_library(lua util.cpp name.cpp numerics.cpp options.cpp sexpr.cpp format.cpp leanlua_state.cpp) add_library(lua util.cpp name.cpp numerics.cpp options.cpp sexpr.cpp
target_link_libraries(lua ${LEAN_LIBS}) format.cpp expr.cpp leanlua_state.cpp)
target_link_libraries(lua ${LEAN_LIBS})

213
src/bindings/lua/expr.cpp Normal file
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@ -0,0 +1,213 @@
/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#ifdef LEAN_USE_LUA
#include <sstream>
#include <lua.hpp>
#include <utility>
#include "util/debug.h"
#include "util/name.h"
#include "util/buffer.h"
#include "kernel/expr.h"
#include "kernel/abstract.h"
#include "library/expr_lt.h"
#include "bindings/lua/util.h"
#include "bindings/lua/name.h"
namespace lean {
constexpr char const * expr_mt = "expr.mt";
bool is_expr(lua_State * L, int idx) {
return testudata(L, idx, expr_mt);
}
expr & to_expr(lua_State * L, int idx) {
return *static_cast<expr*>(luaL_checkudata(L, idx, expr_mt));
}
int push_expr(lua_State * L, expr const & e) {
void * mem = lua_newuserdata(L, sizeof(expr));
new (mem) expr(e);
luaL_getmetatable(L, expr_mt);
lua_setmetatable(L, -2);
return 1;
}
static int expr_gc(lua_State * L) {
to_expr(L, 1).~expr();
return 0;
}
static int expr_tostring(lua_State * L) {
std::ostringstream out;
// TODO(Leo): use pretty printer
out << to_expr(L, 1);
lua_pushfstring(L, out.str().c_str());
return 1;
}
static int expr_eq(lua_State * L) {
lua_pushboolean(L, to_expr(L, 1) == to_expr(L, 2));
return 1;
}
static int expr_lt(lua_State * L) {
lua_pushboolean(L, to_expr(L, 1) < to_expr(L, 2));
return 1;
}
static int expr_mk_constant(lua_State * L) {
return push_expr(L, mk_constant(to_name_ext(L, 1)));
}
static int expr_mk_var(lua_State * L) {
return push_expr(L, mk_var(luaL_checkinteger(L, 1)));
}
static int expr_mk_app(lua_State * L) {
int nargs = lua_gettop(L);
if (nargs < 2)
luaL_error(L, "application must have at least two arguments");
buffer<expr> args;
for (int i = 1; i <= nargs; i++)
args.push_back(to_expr(L, i));
return push_expr(L, mk_app(args));
}
static int expr_mk_eq(lua_State * L) {
return push_expr(L, mk_eq(to_expr(L, 1), to_expr(L, 2)));
}
static int expr_mk_lambda(lua_State * L) {
return push_expr(L, mk_lambda(to_name_ext(L, 1), to_expr(L, 2), to_expr(L, 3)));
}
static int expr_mk_pi(lua_State * L) {
return push_expr(L, mk_lambda(to_name_ext(L, 1), to_expr(L, 2), to_expr(L, 3)));
}
static int expr_mk_let(lua_State * L) {
int nargs = lua_gettop(L);
if (nargs == 3)
return push_expr(L, mk_let(to_name_ext(L, 1), expr(), to_expr(L, 2), to_expr(L, 3)));
else
return push_expr(L, mk_let(to_name_ext(L, 1), to_expr(L, 2), to_expr(L, 3), to_expr(L, 4)));
}
static expr get_expr_from_table(lua_State * L, int t, int i) {
lua_pushvalue(L, t); // push table to the top
lua_pushinteger(L, i);
lua_gettable(L, -2);
expr r = to_expr(L, -1);
lua_pop(L, 2); // remove table and value
return r;
}
// t is a table of pairs {{a1, b1}, ..., {ak, bk}}
// Each ai and bi is an expression
static std::pair<expr, expr> get_expr_pair_from_table(lua_State * L, int t, int i) {
lua_pushvalue(L, t); // push table on the top
lua_pushinteger(L, i);
lua_gettable(L, -2); // now table {ai, bi} is on the top
if (!lua_istable(L, -1) || lua_objlen(L, -1) != 2)
luaL_error(L, "arg #1 must be of the form '{{expr, expr}, ...}'");
expr ai = get_expr_from_table(L, -1, 1);
expr bi = get_expr_from_table(L, -1, 2);
lua_pop(L, 2); // pop table {ai, bi} and t from stack
return mk_pair(ai, bi);
}
static int expr_fun(lua_State * L) {
int nargs = lua_gettop(L);
if (nargs < 2)
luaL_error(L, "Lean fun must have at least 2 arguments");
if (nargs == 2) {
if (!lua_istable(L, 1))
luaL_error(L, "Lean fun expects arg #1 to be of the form '{{expr, expr}, ...}'");
int len = lua_objlen(L, 1);
if (len == 0)
luaL_error(L, "Lean fun expects arg #1 to be non-empty table");
expr r = to_expr(L, 2);
for (int i = len; i >= 1; i--) {
auto p = get_expr_pair_from_table(L, 1, i);
r = Fun(p.first, p.second, r);
}
return push_expr(L, r);
} else {
if (nargs % 2 == 0)
luaL_error(L, "Lean fun must have an odd number of arguments");
expr r = to_expr(L, nargs);
for (int i = nargs - 1; i >= 1; i-=2) {
if (is_expr(L, i - 1))
r = Fun(to_expr(L, i - 1), to_expr(L, i), r);
else
r = Fun(to_name_ext(L, i - 1), to_expr(L, i), r);
}
return push_expr(L, r);
}
}
static int expr_pi(lua_State * L) {
int nargs = lua_gettop(L);
if (nargs < 2)
luaL_error(L, "Lean Pi must have at least 2 arguments");
if (nargs == 2) {
if (!lua_istable(L, 1))
luaL_error(L, "Lean Pi expects arg #1 to be of the form '{{expr, expr}, ...}'");
int len = lua_objlen(L, 1);
if (len == 0)
luaL_error(L, "Lean Pi expects arg #1 to be non-empty table");
expr r = to_expr(L, 2);
for (int i = len; i >= 1; i--) {
auto p = get_expr_pair_from_table(L, 1, i);
r = Pi(p.first, p.second, r);
}
return push_expr(L, r);
} else {
if (nargs % 2 == 0)
luaL_error(L, "Lean Pi must have an odd number of arguments");
expr r = to_expr(L, nargs);
for (int i = nargs - 1; i >= 1; i-=2) {
if (is_expr(L, i - 1))
r = Pi(to_expr(L, i - 1), to_expr(L, i), r);
else
r = Pi(to_name_ext(L, i - 1), to_expr(L, i), r);
}
return push_expr(L, r);
}
}
static const struct luaL_Reg expr_m[] = {
{"__gc", expr_gc}, // never throws
{"__tostring", safe_function<expr_tostring>},
{"__eq", safe_function<expr_eq>},
{"__lt", safe_function<expr_lt>},
{"__call", safe_function<expr_mk_app>},
{0, 0}
};
void open_expr(lua_State * L) {
luaL_newmetatable(L, expr_mt);
lua_pushvalue(L, -1);
lua_setfield(L, -2, "__index");
setfuncs(L, expr_m, 0);
set_global_function<expr_mk_constant>(L, "mk_constant");
set_global_function<expr_mk_constant>(L, "Const");
set_global_function<expr_mk_var>(L, "mk_var");
set_global_function<expr_mk_var>(L, "Var");
set_global_function<expr_mk_app>(L, "mk_app");
set_global_function<expr_mk_eq>(L, "mk_eq");
set_global_function<expr_mk_eq>(L, "Eq");
set_global_function<expr_mk_lambda>(L, "mk_lambda");
set_global_function<expr_mk_pi>(L, "mk_pi");
set_global_function<expr_mk_let>(L, "mk_let");
set_global_function<expr_fun>(L, "fun");
set_global_function<expr_fun>(L, "Fun");
set_global_function<expr_pi>(L, "Pi");
}
}
#endif

16
src/bindings/lua/expr.h Normal file
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@ -0,0 +1,16 @@
/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#ifdef LEAN_USE_LUA
#include <lua.hpp>
namespace lean {
class expr;
void open_expr(lua_State * L);
bool is_expr(lua_State * L, int idx);
expr & to_expr(lua_State * L, int idx);
int push_expr(lua_State * L, expr const & o);
}
#endif

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@ -20,6 +20,7 @@ Author: Leonardo de Moura
#include "bindings/lua/options.h" #include "bindings/lua/options.h"
#include "bindings/lua/sexpr.h" #include "bindings/lua/sexpr.h"
#include "bindings/lua/format.h" #include "bindings/lua/format.h"
#include "bindings/lua/expr.h"
extern "C" void * lua_realloc(void *, void * q, size_t, size_t new_size) { return lean::realloc(q, new_size); } extern "C" void * lua_realloc(void *, void * q, size_t, size_t new_size) { return lean::realloc(q, new_size); }
@ -43,6 +44,7 @@ struct leanlua_state::imp {
lean::open_options(m_state); lean::open_options(m_state);
lean::open_sexpr(m_state); lean::open_sexpr(m_state);
lean::open_format(m_state); lean::open_format(m_state);
lean::open_expr(m_state);
} }
~imp() { ~imp() {
@ -170,7 +172,7 @@ char const * lua_exception::what() const noexcept {
std::ostringstream strm; std::ostringstream strm;
switch (m_source) { switch (m_source) {
case source::String: strm << "[string]:" << m_line << ":" << msg() << "\n"; break; case source::String: strm << "[string]:" << m_line << ":" << msg() << "\n"; break;
case source::File: strm << m_file << ":" << m_file << ":" << msg() << "\n"; break; case source::File: strm << m_file << ":" << m_line << ":" << msg() << "\n"; break;
case source::Unknown: return msg(); case source::Unknown: return msg();
} }
buffer = strm.str(); buffer = strm.str();

13
tests/lua/expr1.lua Normal file
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@ -0,0 +1,13 @@
f = Const("f")
a = Const("a")
print(f(f(a)))
print(mk_lambda("x", Const("N"), Var(0)))
assert(tostring(f(a)) == "f a")
x = Const("x")
y = Const("y")
N = Const("N")
print(fun(x, N, y, N, f(x, y)))
a = {x, N, x, Y}
print(a[1])
print(fun({{x, N}, {y, N}}, f(x, y)))
print(Pi({{x, N}, {y, N}}, f(x, y)))