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Rename (stack) value to svalue

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-08-03 14:16:32 -07:00
parent 0b8fa3b167
commit 1fec8b0d5b
2 changed files with 49 additions and 44 deletions
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91
src/kernel/normalize.cpp
View file

@ -17,42 +17,44 @@ Author: Leonardo de Moura
namespace lean {
class value;
typedef list<value> stack; //!< Normalization stack
enum class value_kind { Expr, Closure, BoundedVar };
class value {
value_kind m_kind;
unsigned m_bvar;
expr m_expr;
stack m_ctx;
class svalue;
typedef list<svalue> stack; //!< Normalization stack
enum class svalue_kind { Expr, Closure, BoundedVar };
/** \brief Stack value: simple expressions, closures and bounded variables. */
class svalue {
svalue_kind m_kind;
unsigned m_bvar;
expr m_expr;
stack m_ctx;
public:
explicit value(expr const & e):m_kind(value_kind::Expr), m_expr(e) {}
explicit value(unsigned k):m_kind(value_kind::BoundedVar), m_bvar(k) {}
value(expr const & e, stack const & c):m_kind(value_kind::Closure), m_expr(e), m_ctx(c) { lean_assert(is_lambda(e)); }
explicit svalue(expr const & e): m_kind(svalue_kind::Expr), m_expr(e) {}
explicit svalue(unsigned k): m_kind(svalue_kind::BoundedVar), m_bvar(k) {}
svalue(expr const & e, stack const & c):m_kind(svalue_kind::Closure), m_expr(e), m_ctx(c) { lean_assert(is_lambda(e)); }
value_kind kind() const { return m_kind; }
svalue_kind kind() const { return m_kind; }
bool is_expr() const { return kind() == value_kind::Expr; }
bool is_closure() const { return kind() == value_kind::Closure; }
bool is_bounded_var() const { return kind() == value_kind::BoundedVar; }
bool is_expr() const { return kind() == svalue_kind::Expr; }
bool is_closure() const { return kind() == svalue_kind::Closure; }
bool is_bounded_var() const { return kind() == svalue_kind::BoundedVar; }
expr const & get_expr() const { lean_assert(is_expr() || is_closure()); return m_expr; }
stack const & get_ctx() const { lean_assert(is_closure()); return m_ctx; }
unsigned get_var_idx() const { lean_assert(is_bounded_var()); return m_bvar; }
};
value_kind kind(value const & v) { return v.kind(); }
expr const & to_expr(value const & v) { return v.get_expr(); }
stack const & stack_of(value const & v) { return v.get_ctx(); }
unsigned to_bvar(value const & v) { return v.get_var_idx(); }
svalue_kind kind(svalue const & v) { return v.kind(); }
expr const & to_expr(svalue const & v) { return v.get_expr(); }
stack const & stack_of(svalue const & v) { return v.get_ctx(); }
unsigned to_bvar(svalue const & v) { return v.get_var_idx(); }
stack extend(stack const & s, value const & v) { return cons(v, s); }
stack extend(stack const & s, svalue const & v) { return cons(v, s); }
/** \brief Expression normalizer. */
class normalize_fn {
environment const & m_env;
context const & m_ctx;
value lookup(stack const & s, unsigned i, unsigned k) {
svalue lookup(stack const & s, unsigned i, unsigned k) {
unsigned j = i;
stack const * it1 = &s;
while (*it1) {
@ -65,17 +67,18 @@ class normalize_fn {
if (c) {
context_entry const & entry = head(c);
if (entry.get_body())
return value(::lean::normalize(entry.get_body(), m_env, tail(c)));
return svalue(::lean::normalize(entry.get_body(), m_env, tail(c)));
else
return value(length(c) - 1);
return svalue(length(c) - 1);
}
throw exception("unknown free variable");
}
expr reify_closure(expr const & a, stack const & c, unsigned k) {
/** \brief Convert the closure \c a into an expression using the given stack in a context that contains \c k binders. */
expr reify_closure(expr const & a, stack const & s, unsigned k) {
lean_assert(is_lambda(a));
expr new_t = reify(normalize(abst_domain(a), c, k), k);
expr new_b = reify(normalize(abst_body(a), extend(c, value(k)), k+1), k+1);
expr new_t = reify(normalize(abst_domain(a), s, k), k);
expr new_b = reify(normalize(abst_body(a), extend(s, svalue(k)), k+1), k+1);
return lambda(abst_name(a), new_t, new_b);
#if 0
// Eta-reduction + Cumulativity + Set theoretic interpretation is unsound.
@ -109,27 +112,29 @@ class normalize_fn {
#endif
}
expr reify(value const & v, unsigned k) {
/** \brief Convert the value \c v back into an expression in a context that contains \c k binders. */
expr reify(svalue const & v, unsigned k) {
lean_trace("normalize", tout << "Reify kind: " << static_cast<unsigned>(v.kind()) << "\n";
if (v.is_bounded_var()) tout << "#" << to_bvar(v); else tout << to_expr(v); tout << "\n";);
switch (v.kind()) {
case value_kind::Expr: return to_expr(v);
case value_kind::BoundedVar: return var(k - to_bvar(v) - 1);
case value_kind::Closure: return reify_closure(to_expr(v), stack_of(v), k);
case svalue_kind::Expr: return to_expr(v);
case svalue_kind::BoundedVar: return var(k - to_bvar(v) - 1);
case svalue_kind::Closure: return reify_closure(to_expr(v), stack_of(v), k);
}
lean_unreachable();
return expr();
}
value normalize(expr const & a, stack const & c, unsigned k) {
/** \brief Normalize the expression \c a in a context composed of stack \c s and \c k binders. */
svalue normalize(expr const & a, stack const & s, unsigned k) {
lean_trace("normalize", tout << "Normalize, k: " << k << "\n" << a << "\n";);
switch (a.kind()) {
case expr_kind::Var:
return lookup(c, var_idx(a), k);
return lookup(s, var_idx(a), k);
case expr_kind::Constant: case expr_kind::Type: case expr_kind::Numeral:
return value(a);
return svalue(a);
case expr_kind::App: {
value f = normalize(arg(a, 0), c, k);
svalue f = normalize(arg(a, 0), s, k);
unsigned i = 1;
unsigned n = num_args(a);
while (true) {
@ -137,8 +142,8 @@ class normalize_fn {
// beta reduction
expr const & fv = to_expr(f);
lean_trace("normalize", tout << "beta reduction...\n" << fv << "\n";);
stack new_c = extend(stack_of(f), normalize(arg(a, i), c, k));
f = normalize(abst_body(fv), new_c, k);
stack new_s = extend(stack_of(f), normalize(arg(a, i), s, k));
f = normalize(abst_body(fv), new_s, k);
if (i == n - 1)
return f;
i++;
@ -148,20 +153,20 @@ class normalize_fn {
buffer<expr> new_args;
new_args.push_back(reify(f, k));
for (; i < n; i++)
new_args.push_back(reify(normalize(arg(a, i), c, k), k));
return value(app(new_args.size(), new_args.data()));
new_args.push_back(reify(normalize(arg(a, i), s, k), k));
return svalue(app(new_args.size(), new_args.data()));
}
}
}
case expr_kind::Lambda:
return value(a, c);
return svalue(a, s);
case expr_kind::Pi: {
expr new_t = reify(normalize(abst_domain(a), c, k), k);
expr new_b = reify(normalize(abst_body(a), extend(c, value(k)), k+1), k+1);
return value(pi(abst_name(a), new_t, new_b));
expr new_t = reify(normalize(abst_domain(a), s, k), k);
expr new_b = reify(normalize(abst_body(a), extend(s, svalue(k)), k+1), k+1);
return svalue(pi(abst_name(a), new_t, new_b));
}}
lean_unreachable();
return value(a);
return svalue(a);
}
public:

2
src/kernel/normalize.h
View file

@ -11,6 +11,6 @@ Author: Leonardo de Moura
namespace lean {
class environment;
/** \brief Normalize e using the environment env and context ctx */
/** \brief Normalize \c e using the environment \c env and context \c ctx */
expr normalize(expr const & e, environment const & env, context const & ctx = context());
}