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perf(kernel/instantiate): add custom instantiate for 'easy' cases

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-07-17 08:29:04 +01:00
parent a78fb8f013
commit 9fcb31bd5e
1 changed files with 23 additions and 0 deletions
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23
src/kernel/instantiate.cpp
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@ -11,9 +11,30 @@ Author: Leonardo de Moura
#include "kernel/instantiate.h"
namespace lean {
template<bool rev>
struct instantiate_easy_fn {
unsigned n;
expr const * subst;
instantiate_easy_fn(unsigned _n, expr const * _subst):n(_n), subst(_subst) {}
optional<expr> operator()(expr const & a, bool app) const {
if (closed(a))
return some_expr(a);
if (is_var(a) && var_idx(a) < n)
return some_expr(subst[rev ? n - var_idx(a) - 1 : var_idx(a)]);
if (app && is_app(a))
if (auto new_a = operator()(app_arg(a), false))
if (auto new_f = operator()(app_fn(a), true))
return some_expr(copy_tag(a, mk_app(*new_f, *new_a)));
return none_expr();
}
};
expr instantiate(expr const & a, unsigned s, unsigned n, expr const * subst) {
if (s >= get_free_var_range(a) || n == 0)
return a;
if (s == 0)
if (auto r = instantiate_easy_fn<false>(n, subst)(a, true))
return *r;
return replace(a, [=](expr const & m, unsigned offset) -> optional<expr> {
unsigned s1 = s + offset;
if (s1 < s)
@ -43,6 +64,8 @@ expr instantiate(expr const & e, expr const & s) { return instantiate(e, 0, s);
expr instantiate_rev(expr const & a, unsigned n, expr const * subst) {
if (closed(a))
return a;
if (auto r = instantiate_easy_fn<true>(n, subst)(a, true))
return *r;
return replace(a, [=](expr const & m, unsigned offset) -> optional<expr> {
if (offset >= get_free_var_range(m))
return some_expr(m); // expression m does not contain free variables with idx >= offset