lean2/src/library/update_expr.cpp

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/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "util/buffer.h"
#include "library/update_expr.h"
namespace lean {
expr update_app(expr const & app, unsigned i, expr const & new_arg) {
if (is_eqp(arg(app, i), new_arg)) {
return app;
} else {
buffer<expr> new_args;
unsigned num = num_args(app);
for (unsigned j = 0; j < num; j++) {
if (i == j)
new_args.push_back(new_arg);
else
new_args.push_back(arg(app, j));
}
return mk_app(new_args);
}
}
expr update_app(expr const & app, unsigned num_new_args, expr const * new_args) {
unsigned i;
unsigned num = num_args(app);
if (num != num_new_args)
return mk_app(num_new_args, new_args);
for (i = 0; i < num; i++) {
if (!is_eqp(arg(app, i), new_args[i]))
break;
}
if (i < num)
return mk_app(num, new_args);
else
return app;
}
expr update_lambda(expr const & lambda, expr const & d, expr const & b) {
if (is_eqp(abst_domain(lambda), d) && is_eqp(abst_body(lambda), b))
return lambda;
else
return mk_lambda(abst_name(lambda), d, b);
}
expr update_pi(expr const & pi, expr const & d, expr const & b) {
if (is_eqp(abst_domain(pi), d) && is_eqp(abst_body(pi), b))
return pi;
else
return mk_pi(abst_name(pi), d, b);
}
expr update_abstraction(expr const & abst, expr const & d, expr const & b) {
if (is_lambda(abst))
return update_lambda(abst, d, b);
else
return update_pi(abst, d, b);
}
expr update_let(expr const & let, expr const & t, expr const & v, expr const & b) {
if (is_eqp(let_type(let), t) && is_eqp(let_value(let), v) && is_eqp(let_body(let), b))
return let;
else
return mk_let(let_name(let), t, v, b);
}
expr update_eq(expr const & eq, expr const & l, expr const & r) {
if (is_eqp(eq_lhs(eq), l) && is_eqp(eq_rhs(eq), r))
return eq;
else
return mk_eq(l, r);
}
}