// Collect the given type parameter
static void collect_type_param(ast_t* orig_param, ast_t* params, ast_t* args)
{
assert(orig_param != NULL);
// Get original type parameter info
AST_GET_CHILDREN(orig_param, id, constraint, deflt);
const char* name = ast_name(id);
constraint = sanitise_type(constraint);
assert(constraint != NULL);
// New type parameter has the same constraint as the old one (sanitised)
if(params != NULL)
{
BUILD(new_param, orig_param,
NODE(TK_TYPEPARAM,
ID(name)
TREE(constraint)
NONE));
ast_append(params, new_param);
ast_setid(params, TK_TYPEPARAMS);
}
// New type arguments binds to old type parameter
if(args != NULL)
{
BUILD(new_arg, orig_param,
NODE(TK_NOMINAL,
NONE // Package
ID(name)
NONE // Type args
NONE // cap
NONE)); // ephemeral
ast_append(args, new_arg);
ast_setid(args, TK_TYPEARGS);
}
}
// Collect the given type parameter
static void collect_type_param(ast_t* orig_param, ast_t* params, ast_t* args)
{
assert(orig_param != NULL);
assert(params != NULL);
assert(args != NULL);
// Get original type parameter info
AST_GET_CHILDREN(orig_param, id, constraint, deflt);
const char* name = ast_name(id);
constraint = sanitise_type(constraint);
assert(constraint != NULL);
// New type parameter has the same constraint as the old one (sanitised)
BUILD(new_param, orig_param,
NODE(TK_TYPEPARAM,
ID(name)
TREE(constraint)
NONE));
ast_append(params, new_param);
// New type arguments binds to old type parameter
BUILD(new_arg, orig_param,
NODE(TK_TYPEPARAMREF, DATA(orig_param)
ID(name)
NONE // cap
NONE)); // ephemeral
ast_append(args, new_arg);
// Since we have a type parameter the params and args node should not be
// TK_NONE
ast_setid(params, TK_TYPEPARAMS);
ast_setid(args, TK_TYPEARGS);
}
// Process the given capture and create the AST for the corresponding field.
// Returns the create field AST, which must be freed by the caller.
// Returns NULL on error.
static ast_t* make_capture_field(pass_opt_t* opt, ast_t* capture)
{
assert(capture != NULL);
AST_GET_CHILDREN(capture, id_node, type, value);
const char* name = ast_name(id_node);
// There are 3 varieties of capture:
// x -> capture variable x, type from defn of x
// x = y -> capture expression y, type inferred from expression type
// x: T = y -> capture expression y, type T
if(ast_id(value) == TK_NONE)
{
// Variable capture
assert(ast_id(type) == TK_NONE);
ast_t* def = ast_get(capture, name, NULL);
if(def == NULL)
{
ast_error(opt->check.errors, id_node,
"cannot capture \"%s\", variable not defined", name);
return NULL;
}
token_id def_id = ast_id(def);
if(def_id != TK_ID && def_id != TK_FVAR && def_id != TK_FLET &&
def_id != TK_PARAM)
{
ast_error(opt->check.errors, id_node, "cannot capture \"%s\", can only "
"capture fields, parameters and local variables", name);
return NULL;
}
BUILD(capture_rhs, id_node, NODE(TK_REFERENCE, ID(name)));
type = alias(ast_type(def));
value = capture_rhs;
} else if(ast_id(type) == TK_NONE) {
// No type specified, use type of the captured expression
type = alias(ast_type(value));
} else {
// Type given, infer literals
if(!coerce_literals(&value, type, opt))
return NULL;
}
if(is_typecheck_error(type))
return NULL;
type = sanitise_type(type);
BUILD(field, id_node,
NODE(TK_FVAR,
TREE(id_node)
TREE(type)
TREE(value)
NONE)); // Delegate type
return field;
}
// Sugar for partial application, which we convert to a lambda.
static bool partial_application(pass_opt_t* opt, ast_t** astp)
{
/* Example that we refer to throughout this function.
* ```pony
* class C
* fun f[T](a: A, b: B = b_default): R
*
* let recv: T = ...
* recv~f[T2](foo)
* ```
*
* Partial call is converted to:
* ```pony
* lambda(b: B = b_default)($0 = recv, a = foo): R => $0.f[T2](a, consume b)
* ```
*/
ast_t* ast = *astp;
typecheck_t* t = &opt->check;
if(!method_application(opt, ast, true))
return false;
AST_GET_CHILDREN(ast, positional, namedargs, lhs);
assert(ast_id(lhs) == TK_FUNAPP || ast_id(lhs) == TK_BEAPP ||
ast_id(lhs) == TK_NEWAPP);
// LHS must be a TK_TILDE, possibly contained in a TK_QUALIFY.
AST_GET_CHILDREN(lhs, receiver, method);
ast_t* type_args = NULL;
switch(ast_id(receiver))
{
case TK_NEWAPP:
case TK_BEAPP:
case TK_FUNAPP:
type_args = method;
AST_GET_CHILDREN_NO_DECL(receiver, receiver, method);
break;
default: {}
}
// The TK_FUNTYPE of the LHS.
ast_t* type = ast_type(lhs);
if(is_typecheck_error(type))
return false;
token_id apply_cap = partial_application_cap(opt, type, receiver,
positional);
AST_GET_CHILDREN(type, cap, type_params, target_params, result);
token_id can_error = ast_canerror(lhs) ? TK_QUESTION : TK_NONE;
const char* recv_name = package_hygienic_id(t);
// Build captures. We always have at least one capture, for receiver.
// Capture: `$0 = recv`
BUILD(captures, receiver,
NODE(TK_LAMBDACAPTURES,
NODE(TK_LAMBDACAPTURE,
ID(recv_name)
NONE // Infer type.
TREE(receiver))));
// Process arguments.
ast_t* given_arg = ast_child(positional);
ast_t* target_param = ast_child(target_params);
ast_t* lambda_params = ast_from(target_params, TK_NONE);
ast_t* lambda_call_args = ast_from(positional, TK_NONE);
while(given_arg != NULL)
{
assert(target_param != NULL);
const char* target_p_name = ast_name(ast_child(target_param));
if(ast_id(given_arg) == TK_NONE)
{
// This argument is not supplied already, must be a lambda parameter.
// Like `b` in example above.
// Build a new a new TK_PARAM node rather than copying the target one,
// since the target has already been processed to expr pass, and we need
// a clean one.
AST_GET_CHILDREN(target_param, p_id, p_type, p_default);
// Parameter: `b: B = b_default`
BUILD(lambda_param, target_param,
NODE(TK_PARAM,
TREE(p_id)
TREE(sanitise_type(p_type))
TREE(p_default)));
ast_append(lambda_params, lambda_param);
ast_setid(lambda_params, TK_PARAMS);
// Argument: `consume b`
BUILD(target_arg, lambda_param,
NODE(TK_SEQ,
NODE(TK_CONSUME,
NONE
NODE(TK_REFERENCE, ID(target_p_name)))));
ast_append(lambda_call_args, target_arg);
ast_setid(lambda_call_args, TK_POSITIONALARGS);
}
else
{
// This argument is supplied to the partial, capture it.
// Like `a` in example above.
// Capture: `a = foo`
BUILD(capture, given_arg,
NODE(TK_LAMBDACAPTURE,
ID(target_p_name)
NONE
TREE(given_arg)));
ast_append(captures, capture);
// Argument: `a`
BUILD(target_arg, given_arg,
NODE(TK_SEQ,
NODE(TK_REFERENCE, ID(target_p_name))));
ast_append(lambda_call_args, target_arg);
ast_setid(lambda_call_args, TK_POSITIONALARGS);
}
given_arg = ast_sibling(given_arg);
target_param = ast_sibling(target_param);
}
assert(target_param == NULL);
// Build lambda expression.
// `$0.f`
BUILD(call_receiver, ast,
NODE(TK_DOT,
NODE(TK_REFERENCE, ID(recv_name))
TREE(method)));
if(type_args != NULL)
{
// The partial call has type args, add them to the actual call in apply().
// `$0.f[T2]`
BUILD(qualified, type_args,
NODE(TK_QUALIFY,
TREE(call_receiver)
TREE(type_args)));
call_receiver = qualified;
}
REPLACE(astp,
NODE(TK_LAMBDA,
NODE(apply_cap)
NONE // Lambda function name.
NONE // Lambda type params.
TREE(lambda_params)
TREE(captures)
TREE(sanitise_type(result))
NODE(can_error)
NODE(TK_SEQ,
NODE(TK_CALL,
TREE(lambda_call_args)
NONE // Named args.
TREE(call_receiver)))));
// Need to preserve various lambda children.
ast_setflag(ast_childidx(*astp, 2), AST_FLAG_PRESERVE); // Type params.
ast_setflag(ast_childidx(*astp, 3), AST_FLAG_PRESERVE); // Parameters.
ast_setflag(ast_childidx(*astp, 5), AST_FLAG_PRESERVE); // Return type.
ast_setflag(ast_childidx(*astp, 7), AST_FLAG_PRESERVE); // Body.
// Catch up to this pass.
return ast_passes_subtree(astp, opt, PASS_EXPR);
}
// Sugar for partial application, which we convert to a lambda.
static bool partial_application(pass_opt_t* opt, ast_t** astp)
{
/* Example that we refer to throughout this function.
* ```pony
* class C
* fun f[T](a: A, b: B = b_default): R
*
* let recv: T = ...
* recv~f[T2](foo)
* ```
*
* Partial call is converted to:
* ```pony
* {(b: B = b_default)($0 = recv, a = foo): R => $0.f[T2](a, consume b) }
* ```
*/
ast_t* ast = *astp;
typecheck_t* t = &opt->check;
if(!method_application(opt, ast, true))
return false;
AST_GET_CHILDREN(ast, positional, namedargs, question, lhs);
// LHS must be an application, possibly wrapped in another application
// if the method had type parameters for qualification.
pony_assert(ast_id(lhs) == TK_FUNAPP || ast_id(lhs) == TK_BEAPP ||
ast_id(lhs) == TK_NEWAPP);
AST_GET_CHILDREN(lhs, receiver, method);
ast_t* type_args = NULL;
if(ast_id(receiver) == ast_id(lhs))
{
type_args = method;
AST_GET_CHILDREN_NO_DECL(receiver, receiver, method);
}
// Look up the original method definition for this method call.
ast_t* method_def = lookup(opt, lhs, ast_type(receiver), ast_name(method));
pony_assert(ast_id(method_def) == TK_FUN || ast_id(method_def) == TK_BE ||
ast_id(method_def) == TK_NEW);
// The TK_FUNTYPE of the LHS.
ast_t* type = ast_type(lhs);
pony_assert(ast_id(type) == TK_FUNTYPE);
if(is_typecheck_error(type))
return false;
AST_GET_CHILDREN(type, cap, type_params, target_params, result);
bool bare = ast_id(cap) == TK_AT;
token_id apply_cap = TK_AT;
if(!bare)
apply_cap = partial_application_cap(opt, type, receiver, positional);
token_id can_error = ast_id(ast_childidx(method_def, 5));
const char* recv_name = package_hygienic_id(t);
// Build lambda expression.
ast_t* call_receiver = NULL;
if(bare)
{
ast_t* arg = ast_child(positional);
while(arg != NULL)
{
if(ast_id(arg) != TK_NONE)
{
ast_error(opt->check.errors, arg, "the partial application of a bare "
"method cannot take arguments");
return false;
}
arg = ast_sibling(arg);
}
ast_t* receiver_type = ast_type(receiver);
if(is_bare(receiver_type))
{
// Partial application on a bare object, simply return the object itself.
ast_replace(astp, receiver);
return true;
}
AST_GET_CHILDREN(receiver_type, recv_type_package, recv_type_name);
const char* recv_package_str = ast_name(recv_type_package);
const char* recv_name_str = ast_name(recv_type_name);
ast_t* module = ast_nearest(ast, TK_MODULE);
ast_t* package = ast_parent(module);
ast_t* pkg_id = package_id(package);
const char* pkg_str = ast_name(pkg_id);
const char* pkg_alias = NULL;
if(recv_package_str != pkg_str)
pkg_alias = package_alias_from_id(module, recv_package_str);
ast_free_unattached(pkg_id);
if(pkg_alias != NULL)
{
// `package.Type.f`
BUILD_NO_DECL(call_receiver, ast,
NODE(TK_DOT,
NODE(TK_DOT,
NODE(TK_REFERENCE, ID(pkg_alias))
ID(recv_name_str))
TREE(method)));
} else {
// `Type.f`
BUILD_NO_DECL(call_receiver, ast,
NODE(TK_DOT,
NODE(TK_REFERENCE, ID(recv_name_str))
TREE(method)));
}
} else {
// `$0.f`
BUILD_NO_DECL(call_receiver, ast,
NODE(TK_DOT,
NODE(TK_REFERENCE, ID(recv_name))
TREE(method)));
}
ast_t* captures = NULL;
if(bare)
{
captures = ast_from(receiver, TK_NONE);
} else {
// Build captures. We always have at least one capture, for receiver.
// Capture: `$0 = recv`
BUILD_NO_DECL(captures, receiver,
NODE(TK_LAMBDACAPTURES,
NODE(TK_LAMBDACAPTURE,
ID(recv_name)
NONE // Infer type.
TREE(receiver))));
}
// Process arguments.
ast_t* target_param = ast_child(target_params);
ast_t* lambda_params = ast_from(target_params, TK_NONE);
ast_t* lambda_call_args = ast_from(positional, TK_NONE);
ast_t* given_arg = ast_child(positional);
while(given_arg != NULL)
{
pony_assert(target_param != NULL);
const char* target_p_name = ast_name(ast_child(target_param));
if(ast_id(given_arg) == TK_NONE)
{
// This argument is not supplied already, must be a lambda parameter.
// Like `b` in example above.
// Build a new a new TK_PARAM node rather than copying the target one,
// since the target has already been processed to expr pass, and we need
// a clean one.
AST_GET_CHILDREN(target_param, p_id, p_type, p_default);
// Parameter: `b: B = b_default`
BUILD(lambda_param, target_param,
NODE(TK_PARAM,
TREE(p_id)
TREE(sanitise_type(p_type))
TREE(p_default)));
ast_append(lambda_params, lambda_param);
ast_setid(lambda_params, TK_PARAMS);
// Argument: `consume b`
BUILD(target_arg, lambda_param,
NODE(TK_SEQ,
NODE(TK_CONSUME,
NONE
NODE(TK_REFERENCE, ID(target_p_name)))));
ast_append(lambda_call_args, target_arg);
ast_setid(lambda_call_args, TK_POSITIONALARGS);
}
else
{
// This argument is supplied to the partial, capture it.
// Like `a` in example above.
// Capture: `a = foo`
BUILD(capture, given_arg,
NODE(TK_LAMBDACAPTURE,
ID(target_p_name)
NONE
TREE(given_arg)));
ast_append(captures, capture);
// Argument: `a`
BUILD(target_arg, given_arg,
NODE(TK_SEQ,
NODE(TK_REFERENCE, ID(target_p_name))));
ast_append(lambda_call_args, target_arg);
ast_setid(lambda_call_args, TK_POSITIONALARGS);
}
given_arg = ast_sibling(given_arg);
target_param = ast_sibling(target_param);
}
pony_assert(target_param == NULL);
if(type_args != NULL)
{
// The partial call has type args, add them to the actual call in apply().
// `$0.f[T2]`
BUILD(qualified, type_args,
NODE(TK_QUALIFY,
TREE(call_receiver)
TREE(type_args)));
call_receiver = qualified;
}
REPLACE(astp,
NODE((bare ? TK_BARELAMBDA : TK_LAMBDA),
NODE(apply_cap)
NONE // Lambda function name.
NONE // Lambda type params.
TREE(lambda_params)
TREE(captures)
TREE(sanitise_type(result))
NODE(can_error)
NODE(TK_SEQ,
NODE(TK_CALL,
TREE(lambda_call_args)
NONE // Named args.
NODE(can_error)
TREE(call_receiver)))
NONE)); // Lambda reference capability.
// Need to preserve various lambda children.
ast_setflag(ast_childidx(*astp, 2), AST_FLAG_PRESERVE); // Type params.
ast_setflag(ast_childidx(*astp, 3), AST_FLAG_PRESERVE); // Parameters.
ast_setflag(ast_childidx(*astp, 5), AST_FLAG_PRESERVE); // Return type.
ast_setflag(ast_childidx(*astp, 7), AST_FLAG_PRESERVE); // Body.
// Catch up to this pass.
return ast_passes_subtree(astp, opt, PASS_EXPR);
}
static bool capture_from_reference(pass_opt_t* opt, ast_t* ctx, ast_t* ast,
ast_t* captures, ast_t** last_capture)
{
const char* name = ast_name(ast_child(ast));
if(is_name_dontcare(name))
return true;
ast_t* refdef = ast_get(ast, name, NULL);
if(refdef != NULL)
return true;
refdef = ast_get(ctx, name, NULL);
if(refdef == NULL)
{
ast_error(opt->check.errors, ast,
"cannot capture \"%s\", variable not defined", name);
return false;
}
if(!def_before_use(opt, refdef, ctx, name))
return false;
switch(ast_id(refdef))
{
case TK_VAR:
case TK_LET:
case TK_PARAM:
case TK_MATCH_CAPTURE:
case TK_FVAR:
case TK_FLET:
case TK_EMBED:
break;
default:
ast_error(opt->check.errors, ast, "cannot capture \"%s\", can only "
"capture fields, parameters and local variables", name);
return NULL;
}
// Check if we've already captured it
for(ast_t* p = ast_child(captures); p != NULL; p = ast_sibling(p))
{
AST_GET_CHILDREN(p, c_name, c_type);
if(name == ast_name(c_name))
return true;
}
ast_t* type = alias(ast_type(refdef));
if(is_typecheck_error(type))
return false;
type = sanitise_type(type);
BUILD(field, ast,
NODE(TK_FVAR,
ID(name)
TREE(type)
NODE(TK_REFERENCE, ID(name))));
ast_list_append(captures, last_capture, field);
return true;
}
// Process the given capture and create the AST for the corresponding field.
// Returns the create field AST in out_field, which must be freed by the caller,
// or NULL if there is no field to create.
// Returns false on error.
static bool make_capture_field(pass_opt_t* opt, ast_t* capture,
ast_t** out_field)
{
pony_assert(capture != NULL);
pony_assert(out_field != NULL);
AST_GET_CHILDREN(capture, id_node, type, value);
const char* name = ast_name(id_node);
bool is_dontcare = is_name_dontcare(name);
// There are 3 varieties of capture:
// x -> capture variable x, type from defn of x
// x = y -> capture expression y, type inferred from expression type
// x: T = y -> capture expression y, type T
if(ast_id(value) == TK_NONE)
{
// Variable capture
pony_assert(ast_id(type) == TK_NONE);
if(is_dontcare)
{
*out_field = NULL;
return true;
}
ast_t* def = ast_get(capture, name, NULL);
if(def == NULL)
{
ast_error(opt->check.errors, id_node,
"cannot capture \"%s\", variable not defined", name);
return false;
}
// lambda captures used before their declaration with their type
// not defined are not legal
if(!def_before_use(opt, def, capture, name))
return false;
switch(ast_id(def))
{
case TK_VAR:
case TK_LET:
case TK_PARAM:
case TK_MATCH_CAPTURE:
case TK_FVAR:
case TK_FLET:
case TK_EMBED:
break;
default:
ast_error(opt->check.errors, id_node, "cannot capture \"%s\", can only "
"capture fields, parameters and local variables", name);
return false;
}
BUILD(capture_rhs, id_node, NODE(TK_REFERENCE, ID(name)));
type = alias(ast_type(def));
value = capture_rhs;
} else if(ast_id(type) == TK_NONE) {
// No type specified, use type of the captured expression
if(ast_type(value) == NULL)
return false;
type = alias(ast_type(value));
} else {
// Type given, infer literals
if(!coerce_literals(&value, type, opt))
return false;
// Check subtyping now if we're capturing into '_', since the field will be
// discarded.
if(is_dontcare)
{
ast_t* v_type = alias(ast_type(value));
errorframe_t info = NULL;
if(!is_subtype(v_type, type, &info, opt))
{
errorframe_t frame = NULL;
ast_error_frame(&frame, value, "argument not a subtype of parameter");
errorframe_append(&frame, &info);
errorframe_report(&frame, opt->check.errors);
ast_free_unattached(v_type);
return false;
}
ast_free_unattached(v_type);
}
}
if(is_typecheck_error(type))
return false;
if(is_dontcare)
{
*out_field = NULL;
return true;
}
type = sanitise_type(type);
BUILD(field, id_node,
NODE(TK_FVAR,
TREE(id_node)
TREE(type)
TREE(value)));
*out_field = field;
return true;
}
