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refactor(kernel): replace_fn functional object

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-02-28 16:57:25 -08:00
parent 3939b93c2d
commit 3651b4ecd0
7 changed files with 40 additions and 40 deletions
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12
src/kernel/abstract.cpp
View file

@ -13,26 +13,26 @@ Author: Leonardo de Moura
namespace lean {
expr abstract(expr const & e, unsigned n, expr const * s) {
lean_assert(std::all_of(s, s+n, closed));
return replace(e, [=](expr const & e, unsigned offset) -> expr {
return replace(e, [=](expr const & e, unsigned offset) -> optional<expr> {
unsigned i = n;
while (i > 0) {
--i;
if (s[i] == e)
return mk_var(offset + n - i - 1);
return some_expr(mk_var(offset + n - i - 1));
}
return e;
return none_expr();
});
}
expr abstract_p(expr const & e, unsigned n, expr const * s) {
lean_assert(std::all_of(s, s+n, closed));
return replace(e, [=](expr const & e, unsigned offset) -> expr {
return replace(e, [=](expr const & e, unsigned offset) -> optional<expr> {
unsigned i = n;
while (i > 0) {
--i;
if (is_eqp(s[i], e))
return mk_var(offset + n - i - 1);
return some_expr(mk_var(offset + n - i - 1));
}
return e;
return none_expr();
});
}
#define MkBinder(FName) \

12
src/kernel/free_vars.cpp
View file

@ -285,12 +285,12 @@ expr lower_free_vars(expr const & e, unsigned s, unsigned d) {
return e;
lean_assert(s >= d);
lean_assert(!has_free_var(e, s-d, s));
return replace(e, [=](expr const & e, unsigned offset) -> expr {
return replace(e, [=](expr const & e, unsigned offset) -> optional<expr> {
if (is_var(e) && var_idx(e) >= s + offset) {
lean_assert(var_idx(e) >= offset + d);
return mk_var(var_idx(e) - d);
return some_expr(mk_var(var_idx(e) - d));
} else {
return e;
return none_expr();
}
});
}
@ -299,11 +299,11 @@ expr lower_free_vars(expr const & e, unsigned d) { return lower_free_vars(e, d,
expr lift_free_vars(expr const & e, unsigned s, unsigned d) {
if (d == 0 || closed(e))
return e;
return replace(e, [=](expr const & e, unsigned offset) -> expr {
return replace(e, [=](expr const & e, unsigned offset) -> optional<expr> {
if (is_var(e) && var_idx(e) >= s + offset) {
return mk_var(var_idx(e) + d);
return some_expr(mk_var(var_idx(e) + d));
} else {
return e;
return none_expr();
}
});
}

19
src/kernel/instantiate.cpp
View file

@ -13,24 +13,21 @@ Author: Leonardo de Moura
namespace lean {
template<bool ClosedSubst>
expr instantiate_core(expr const & a, unsigned s, unsigned n, expr const * subst) {
return replace(a, [=](expr const & m, unsigned offset) -> expr {
return replace(a, [=](expr const & m, unsigned offset) -> optional<expr> {
if (is_var(m)) {
unsigned vidx = var_idx(m);
if (vidx >= offset + s) {
if (vidx < offset + s + n) {
if (ClosedSubst)
return subst[vidx - s - offset];
return some_expr(subst[vidx - s - offset]);
else
return lift_free_vars(subst[vidx - s - offset], offset);
return some_expr(lift_free_vars(subst[vidx - s - offset], offset));
} else {
return mk_var(vidx - n);
return some_expr(mk_var(vidx - n));
}
} else {
return m;
}
} else {
return m;
}
return none_expr();
});
}
@ -95,11 +92,11 @@ expr head_beta_reduce(expr const & t) {
}
expr beta_reduce(expr t) {
auto f = [=](expr const & m, unsigned) -> expr {
auto f = [=](expr const & m, unsigned) -> optional<expr> {
if (is_head_beta(m))
return head_beta_reduce(m);
return some_expr(head_beta_reduce(m));
else
return m;
return none_expr();
};
while (true) {
expr new_t = replace_fn(f)(t);

8
src/kernel/normalizer.cpp
View file

@ -95,16 +95,16 @@ class normalizer::imp {
/** \brief Convert the value \c v back into an expression in a context that contains \c k binders. */
expr reify(expr const & v, unsigned k) {
return replace(v, [&](expr const & e, unsigned DEBUG_CODE(offset)) -> expr {
return replace(v, [&](expr const & e, unsigned DEBUG_CODE(offset)) -> optional<expr> {
lean_assert(offset == 0);
lean_assert(!is_lambda(e) && !is_pi(e) && !is_sigma(e) && !is_let(e));
if (is_var(e)) {
// de Bruijn level --> de Bruijn index
return mk_var(k - var_idx(e) - 1);
return some_expr(mk_var(k - var_idx(e) - 1));
} else if (is_closure(e)) {
return reify_closure(to_closure(e), k);
return some_expr(reify_closure(to_closure(e), k));
} else {
return e;
return none_expr();
}
});
}

9
src/kernel/replace_fn.cpp
View file

@ -31,9 +31,12 @@ bool replace_fn::visit(expr const & e, unsigned offset) {
shared = true;
}
expr r = m_f(e, offset);
if (is_atomic(r) || !is_eqp(e, r)) {
save_result(e, r, offset, shared);
optional<expr> r = m_f(e, offset);
if (r) {
save_result(e, *r, offset, shared);
return true;
} else if (is_atomic(e)) {
save_result(e, e, offset, shared);
return true;
} else {
m_fs.emplace_back(e, offset, shared);

2
src/kernel/replace_fn.h
View file

@ -46,7 +46,7 @@ class replace_fn {
typedef buffer<expr> result_stack;
expr_cell_offset_map<expr> m_cache;
std::function<expr(expr const &, unsigned)> m_f;
std::function<optional<expr>(expr const &, unsigned)> m_f;
std::function<void(expr const &, expr const &)> m_post;
frame_stack m_fs;
result_stack m_rs;

10
src/tests/kernel/replace.cpp
View file

@ -74,17 +74,17 @@ static void tst3() {
expr d = Const("d");
expr A = Const("A");
expr_map<expr> trace;
auto proc = [&](expr const & x, unsigned offset) -> expr {
auto proc = [&](expr const & x, unsigned offset) -> optional<expr> {
if (is_var(x)) {
unsigned vidx = var_idx(x);
if (vidx == offset)
return c;
return some_expr(c);
else if (vidx > offset)
return mk_var(vidx-1);
return some_expr(mk_var(vidx-1));
else
return x;
return none_expr();
} else {
return x;
return none_expr();
}
};
replace_fn replacer(proc, tracer(trace));