// Check that the given method is compatible with the existing definition.
// Return the method that ends up being in the entity or NULL on error.
// Stages 2A, 2B and 2C.
static ast_t* add_method(ast_t* entity, ast_t* existing_method,
ast_t* new_method, ast_t** last_method)
{
assert(entity != NULL);
assert(new_method != NULL);
assert(last_method != NULL);
const char* name = ast_name(ast_childidx(new_method, 1));
const char* entity_name = ast_name(ast_child(entity));
if(existing_method == NULL)
{
// This method is new to the entity.
// Stage 2C.
ast_t* case_clash = ast_get_case(entity, name, NULL);
if(case_clash != NULL)
{
ast_error(case_clash, "in %s method name %s differs only in case",
entity_name, name);
ast_error(new_method, "clashing method is here");
return NULL;
}
attach_method_t(new_method, NULL, false);
ast_list_append(ast_childidx(entity, 4), last_method, new_method);
ast_set(entity, name, new_method, SYM_DEFINED);
return *last_method;
}
method_t* info = (method_t*)ast_data(existing_method);
assert(info != NULL);
if(info->local_def)
{
// Existing method is a local definition, new method must be a subtype
// Stage 2A
if(is_subtype(existing_method, new_method, true))
return existing_method;
ast_error(existing_method,
"local method %s is not compatible with provided version", name);
ast_error(new_method, "clashing method is here");
return NULL;
}
// Both method versions came from the provides list, their signatures must
// match exactly
// Stage 2B
if(compare_signatures(existing_method, new_method))
return existing_method;
ast_error(entity, "clashing definitions of method %s provided, local "
"disambiguation required", name);
ast_error(existing_method, "provided here");
ast_error(new_method, "and here");
return NULL;
}
// Setup a method_t structure for each method in the given type
static void setup_local_methods(ast_t* ast)
{
assert(ast != NULL);
ast_t* members = ast_childidx(ast, 4);
assert(members != NULL);
for(ast_t* p = ast_child(members); p != NULL; p = ast_sibling(p))
{
if(is_method(p))
attach_method_t(p, ast, true);
}
}
// Setup a method_t structure for each method in the given type.
static void setup_local_methods(ast_t* ast)
{
assert(ast != NULL);
ast_t* members = ast_childidx(ast, 4);
assert(members != NULL);
for(ast_t* p = ast_child(members); p != NULL; p = ast_sibling(p))
{
if(is_method(p))
{
method_t* info = attach_method_t(p);
info->local_define = true;
if(ast_id(ast_childidx(p, 6)) != TK_NONE)
info->body_donor = ast;
}
}
}
// Add a new method to the given entity, based on the specified method from
// the specified type.
// The trait_ref is the entry in the provides / delegates list that causes this
// method inclusion. Needed for error reporting.
// The basis_method is the reified method in the trait to add.
// The adjective parameter is used for error reporting and should be "provided"
// or similar.
// Return the newly added method or NULL on error.
static ast_t* add_method(ast_t* entity, ast_t* trait_ref, ast_t* basis_method,
const char* adjective, pass_opt_t* opt)
{
assert(entity != NULL);
assert(trait_ref != NULL);
assert(basis_method != NULL);
assert(adjective != NULL);
const char* name = ast_name(ast_childidx(basis_method, 1));
// Check behaviour compatability.
if(ast_id(basis_method) == TK_BE)
{
switch(ast_id(entity))
{
case TK_PRIMITIVE:
ast_error(opt->check.errors, trait_ref,
"cannot add a behaviour (%s) to a primitive", name);
return NULL;
case TK_STRUCT:
ast_error(opt->check.errors, trait_ref,
"cannot add a behaviour (%s) to a struct", name);
return NULL;
case TK_CLASS:
ast_error(opt->check.errors, trait_ref,
"cannot add a behaviour (%s) to a class", name);
return NULL;
default:
break;
}
}
// Check for existing method of the same name.
ast_t* existing = ast_get(entity, name, NULL);
if(existing != NULL)
{
assert(is_field(existing)); // Should already have checked for methods.
ast_error(opt->check.errors, trait_ref,
"%s method '%s' clashes with field", adjective, name);
ast_error_continue(opt->check.errors, basis_method,
"method is defined here");
return NULL;
}
// Check for clash with existing method.
ast_t* case_clash = ast_get_case(entity, name, NULL);
if(case_clash != NULL)
{
const char* clash_name = "";
switch(ast_id(case_clash))
{
case TK_FUN:
case TK_BE:
case TK_NEW:
clash_name = ast_name(ast_childidx(case_clash, 1));
break;
case TK_LET:
case TK_VAR:
case TK_EMBED:
clash_name = ast_name(ast_child(case_clash));
break;
default:
assert(0);
break;
}
ast_error(opt->check.errors, trait_ref,
"%s method '%s' differs only in case from '%s'",
adjective, name, clash_name);
ast_error_continue(opt->check.errors, basis_method,
"clashing method is defined here");
return NULL;
}
AST_GET_CHILDREN(basis_method, cap, id, typeparams, params, result,
can_error, body, doc);
// Ignore docstring.
if(ast_id(doc) == TK_STRING)
{
ast_set_name(doc, "");
ast_setid(doc, TK_NONE);
}
ast_t* local = ast_append(ast_childidx(entity, 4), basis_method);
ast_set(entity, name, local, SYM_DEFINED, false);
ast_t* body_donor = (ast_t*)ast_data(basis_method);
method_t* info = attach_method_t(local);
info->trait_ref = trait_ref;
if(ast_id(body) != TK_NONE)
info->body_donor = body_donor;
return local;
}
