lists.c

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/* -*- C -*-
 * Serene programming language
 * Copyright (C) 2019-2026 Sameer Rahmani <[email protected]>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <https://www.gnu.org/licenses/>.
 */
#include "serene/rt/lists.h"
 
#include "serene/rt/context.h"
#include "serene/rt/core.h"
#include "serene/rt/errors.h"
#include "serene/utils.h"
 
srn_value_t *srn_list_make(
  srn_context_t *ctx, srn_metadata_t *metadata, srn_value_t *const *items, size_t count
) {
  PANIC_IF_NULL(ctx);
  if (count == 0) {
    return &nil_v;
  }
  PANIC_IF_NULL(items);
 
  // Build the chain from the tail back to the head so each node's `next`
  // already points at an initialized successor.
  srn_list_node_t *head = nullptr;
  for (size_t i = count; i-- > 0;) {
    srn_list_node_t *node = ALLOC(ctx, srn_list_node_t);
    node->value           = items[i];
    node->next            = head;
    head                  = node;
  }
 
  srn_list_t *list = ALLOC(ctx, srn_list_t);
  list->len        = count;
  list->head       = head;
  return srn_value_make(ctx, VList, metadata, (void *)list);
}
 
srn_value_t *
srn_list_cons(srn_context_t *ctx, srn_metadata_t *metadata, srn_value_t *value, srn_value_t *list) {
  PANIC_IF_NULL(ctx);
  PANIC_IF_NULL(value);
  PANIC_IF_NULL(list);
 
  srn_list_node_t *next_head = nullptr;
  size_t next_len            = 0;
  if (!IS_NIL(list)) {
    if (!IS_A(list, VList)) {
      return srn_errors_make_error(ctx, metadata, ABSURD, "expected a list");
    }
    srn_list_t *l = AS_LIST(list);
    next_head     = l->head;
    next_len      = l->len;
  }
 
  srn_list_node_t *node = ALLOC(ctx, srn_list_node_t);
  node->value           = value;
  node->next            = next_head;
 
  srn_list_t *result = ALLOC(ctx, srn_list_t);
  result->len        = next_len + 1;
  result->head       = node;
  return srn_value_make(ctx, VList, metadata, (void *)result);
}