Make make_case_for throw from the second time on.

Also clean up the errors thrown a little bit.
This commit is contained in:
Danila Fedorin 2020-09-10 14:03:04 -07:00
parent ca395b5c09
commit 76675fbc9b

View File

@ -228,8 +228,6 @@ struct case_mappings {
std::optional<std::vector<instruction_ptr>> default_case;
std::vector<instruction_ptr>& make_case_for(tag_type tag) {
auto existing_case = defined_cases.find(tag);
if(existing_case != defined_cases.end()) return existing_case->second;
if(default_case)
throw type_error("attempted pattern match after catch-all");
return defined_cases[tag];
@ -279,7 +277,9 @@ struct case_strategy_bool {
if(!(cpat = dynamic_cast<pattern_constr*>(pt.get())) ||
(cpat->constr != "True" && cpat->constr != "False") ||
cpat->params.size() != 0)
throw type_error("pattern cannot be converted to a boolean");
throw type_error(
"pattern cannot be converted to a boolean",
pt->loc);
return cpat->constr == "True";
}
@ -321,7 +321,9 @@ struct case_strategy_data {
repr_type from_typed_pattern(const pattern_ptr& pt, const type* type) {
pattern_constr* cpat;
if(!(cpat = dynamic_cast<pattern_constr*>(pt.get())))
throw type_error("pattern cannot be interpreted as constructor.");
throw type_error(
"pattern cannot be interpreted as constructor.",
pt->loc);
return std::make_pair(
&static_cast<const type_data*>(type)->constructors.find(cpat->constr)->second,
&cpat->params);
@ -383,6 +385,8 @@ void compile_case(const ast_case& node, const env_ptr& env, const type* type, st
for(auto& branch : node.branches) {
pattern_var* vpat;
if((vpat = dynamic_cast<pattern_var*>(branch->pat.get()))) {
if(cases.defined_cases_count() == strategy.case_count(type))
throw type_error("redundant catch-all pattern", branch->pat->loc);
auto& branch_into = cases.make_default_case();
env_ptr new_env(new env_var(branch->expr->env->get_mangled_name(vpat->var), env));
branch->expr->compile(new_env, branch_into);
@ -589,5 +593,5 @@ void pattern_constr::typecheck(type_ptr t, type_mgr& mgr, type_env_ptr& env) con
constructor_type = arr->right;
}
mgr.unify(constructor_type, t, loc);
mgr.unify(t, constructor_type, loc);
}