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feat(library/definitional/equations): add "complete" transition for overlapping patterns

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This commit is contained in:
Leonardo de Moura 2015-01-05 11:49:27 -08:00
parent fdef3e5407
commit b46c377aa2
2 changed files with 62 additions and 4 deletions
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44
src/library/definitional/equations.cpp
View file

@ -305,6 +305,8 @@ class equation_compiler_fn {
expr m_rhs; // right-hand-side
eqn(list<expr> const & c, list<expr> const & p, expr const & r):
m_local_context(c), m_patterns(p), m_rhs(r) {}
eqn(eqn const & e, list<expr> const & c, list<expr> const & p):
eqn(c, p, e.m_rhs) {}
};
// Data-structure used to store for compiling pattern matching.
@ -328,6 +330,8 @@ class equation_compiler_fn {
program(p.m_fn, p.m_context, new_s, new_e, p.m_type) {}
program(program const & p, list<expr> const & ctx):
program(p.m_fn, ctx, p.m_var_stack, p.m_eqns, p.m_type) {}
program(program const & p, list<eqn> const & new_e):
program(p, p.m_var_stack, new_e) {}
program() {}
expr const & get_var(name const & n) const {
for (expr const & v : m_context) {
@ -777,13 +781,45 @@ class equation_compiler_fn {
return compile_variable(p);
}
expr compile_complete(program const & /* p */) {
expr mk_constructor(name const & n, levels const & ls, buffer<expr> const & params, buffer<expr> & args) {
expr c = mk_app(mk_constant(n, ls), params);
expr t = infer_type(c);
to_telescope_ext(t, args);
return mk_app(c, args);
}
expr compile_complete(program const & prg) {
// The next pattern of every equation is a constructor or variable.
// We split the equations where the next pattern is a variable into cases.
// That is, we are reducing this case to the compile_constructor case.
// TODO(Leo)
return expr();
buffer<eqn> new_eqns;
for (eqn const & e : prg.m_eqns) {
expr const & p = head(e.m_patterns);
if (is_local(p)) {
list<expr> rest_ctx = remove(e.m_local_context, p);
expr x = prg.get_var(*head(prg.m_var_stack));
expr x_type = whnf(mlocal_type(x));
buffer<expr> I_args;
expr const & I = get_app_args(x_type, I_args);
name const & I_name = const_name(I);
levels const & I_ls = const_levels(I);
unsigned nparams = *inductive::get_num_params(env(), I_name);
buffer<expr> I_params;
I_params.append(nparams, I_args.data());
buffer<name> constructor_names;
get_intro_rule_names(env(), I_name, constructor_names);
for (name const & c_name : constructor_names) {
buffer<expr> new_args;
expr c = mk_constructor(c_name, I_ls, I_params, new_args);
list<expr> new_ctx = to_list(new_args.begin(), new_args.end(), rest_ctx);
list<expr> new_patterns = cons(c, tail(e.m_patterns));
new_eqns.push_back(eqn(e, new_ctx, new_patterns));
}
} else {
new_eqns.push_back(e);
}
}
return compile_core(program(prg, to_list(new_eqns)));
}
expr compile_core(program const & p) {

22
tests/lean/run/eq11.lean Normal file
View file

@ -0,0 +1,22 @@
inductive day :=
monday, tuesday, wednesday, thursday, friday, saturday, sunday
open day
definition next_weekday : day → day,
next_weekday monday := tuesday,
next_weekday tuesday := wednesday,
next_weekday wednesday := thursday,
next_weekday thursday := friday,
next_weekday _ := monday
theorem next_weekday_monday : next_weekday monday = tuesday := rfl
theorem next_weekday_tuesday : next_weekday tuesday = wednesday := rfl
theorem next_weekday_wednesday : next_weekday wednesday = thursday := rfl
theorem next_weekday_thursday : next_weekday thursday = friday := rfl
theorem next_weekday_friday : next_weekday friday = monday := rfl
theorem next_weekday_sat : next_weekday saturday = monday := rfl
theorem next_weekday_sunday : next_weekday sunday = monday := rfl
example : next_weekday (next_weekday monday) = wednesday :=
rfl