Simplify node construction API

13 files changed, 365 insertions, 294 deletions

diff --git a/include/serd/env.h b/include/serd/env.h
index 7a03e80d..db2c1150 100644
--- a/include/serd/env.h
+++ b/include/serd/env.h
@@ -9,7 +9,6 @@
 #include "serd/sink.h"
 #include "serd/status.h"
 #include "serd/string_view.h"
-#include "serd/uri.h"
 
 #include <stdbool.h>
 
@@ -26,21 +25,19 @@ typedef struct SerdEnvImpl SerdEnv;
 
 /// Create a new environment
 SERD_API SerdEnv* SERD_ALLOCATED
-serd_env_new(const SerdNode* SERD_NULLABLE base_uri);
+serd_env_new(SerdStringView base_uri);
 
 /// Free `env`
 SERD_API void
 serd_env_free(SerdEnv* SERD_NULLABLE env);
 
 /// Get the current base URI
-SERD_API const SerdNode* SERD_NULLABLE
-serd_env_base_uri(const SerdEnv* SERD_NONNULL env,
-                  SerdURIView* SERD_NULLABLE  out);
+SERD_PURE_API const SerdNode* SERD_NULLABLE
+serd_env_base_uri(const SerdEnv* SERD_NULLABLE env);
 
 /// Set the current base URI
 SERD_API SerdStatus
-serd_env_set_base_uri(SerdEnv* SERD_NONNULL         env,
-                      const SerdNode* SERD_NULLABLE uri);
+serd_env_set_base_uri(SerdEnv* SERD_NONNULL env, SerdStringView uri);
 
 /**
    Set a namespace prefix.
@@ -50,15 +47,9 @@ serd_env_set_base_uri(SerdEnv* SERD_NONNULL         env,
    expand to "http://www.w3.org/2001/XMLSchema#decimal".
 */
 SERD_API SerdStatus
-serd_env_set_prefix(SerdEnv* SERD_NONNULL        env,
-                    const SerdNode* SERD_NONNULL name,
-                    const SerdNode* SERD_NONNULL uri);
-
-/// Set a namespace prefix
-SERD_API SerdStatus
-serd_env_set_prefix_from_strings(SerdEnv* SERD_NONNULL    env,
-                                 const char* SERD_NONNULL name,
-                                 const char* SERD_NONNULL uri);
+serd_env_set_prefix(SerdEnv* SERD_NONNULL env,
+                    SerdStringView        name,
+                    SerdStringView        uri);
 
 /// Qualify `uri` into a CURIE if possible
 SERD_API bool
diff --git a/include/serd/node.h b/include/serd/node.h
index 4aa4ec0a..cbf5efcc 100644
--- a/include/serd/node.h
+++ b/include/serd/node.h
@@ -100,29 +100,40 @@ typedef uint32_t SerdNodeFlags;
 */
 
 /**
-   Create a new node from `str`.
+   Create a new simple "token" node.
+
+   A "token" is a node that isn't a typed or tagged literal.  This can be used
+   to create URIs, blank nodes, CURIEs, and simple string literals.
 */
 SERD_API SerdNode* SERD_ALLOCATED
-serd_new_string(SerdNodeType type, const char* SERD_NULLABLE str);
+serd_new_token(SerdNodeType type, SerdStringView string);
 
 /**
-   Create a new node from a prefix of `str`.
+   Create a new string literal node.
 */
 SERD_API SerdNode* SERD_ALLOCATED
-serd_new_substring(SerdNodeType              type,
-                   const char* SERD_NULLABLE str,
-                   size_t                    len);
+serd_new_string(SerdStringView string);
 
 /**
    Create a new literal node from `str`.
 
-   Either `datatype` or `lang` can be given, but not both, unless `datatype` is
-   rdf:langString in which case it is ignored.
+   Either `datatype_uri` or `lang` can be given, but not both, unless
+   `datatype_uri` is rdf:langString in which case it is ignored.
 */
 SERD_API SerdNode* SERD_ALLOCATED
-serd_new_literal(const char* SERD_NONNULL  str,
-                 const char* SERD_NULLABLE datatype,
-                 const char* SERD_NULLABLE lang);
+serd_new_literal(SerdStringView string,
+                 SerdStringView datatype_uri,
+                 SerdStringView lang);
+
+/**
+   Create a new node from a blank node label.
+*/
+SERD_API SerdNode* SERD_ALLOCATED
+serd_new_blank(SerdStringView string);
+
+/// Create a new CURIE node
+SERD_API SerdNode* SERD_ALLOCATED
+serd_new_curie(SerdStringView string);
 
 /**
    Create a new URI node from a parsed URI.
@@ -134,7 +145,7 @@ serd_new_parsed_uri(SerdURIView uri);
    Create a new URI node from a string.
 */
 SERD_API SerdNode* SERD_ALLOCATED
-serd_new_uri(const char* SERD_NONNULL str);
+serd_new_uri(SerdStringView string);
 
 /**
    Create a new file URI node from a file system path and optional hostname.
@@ -143,12 +154,9 @@ serd_new_uri(const char* SERD_NONNULL str);
    percent encoded as necessary.
 
    If `path` is relative, `hostname` is ignored.
-   If `out` is not NULL, it will be set to the parsed URI.
 */
 SERD_API SerdNode* SERD_ALLOCATED
-serd_new_file_uri(const char* SERD_NONNULL   path,
-                  const char* SERD_NULLABLE  hostname,
-                  SerdURIView* SERD_NULLABLE out);
+serd_new_file_uri(SerdStringView path, SerdStringView hostname);
 
 /**
    Create a new node by serialising `d` into an xsd:decimal string.
@@ -237,7 +245,7 @@ serd_node_string_view(const SerdNode* SERD_NONNULL node);
    idea to keep the value if you will be using it several times in the same
    scope.
 */
-SERD_API SerdURIView
+SERD_PURE_API SerdURIView
 serd_node_uri_view(const SerdNode* SERD_NONNULL node);
 
 /**
diff --git a/include/serd/writer.h b/include/serd/writer.h
index 3327c1b9..976ed5b7 100644
--- a/include/serd/writer.h
+++ b/include/serd/writer.h
@@ -48,12 +48,11 @@ typedef uint32_t SerdWriterFlags;
 
 /// Create a new RDF writer
 SERD_API SerdWriter* SERD_ALLOCATED
-serd_writer_new(SerdSyntax                    syntax,
-                SerdWriterFlags               flags,
-                SerdEnv* SERD_NONNULL         env,
-                const SerdNode* SERD_NULLABLE base_uri,
-                SerdSink SERD_NONNULL         ssink,
-                void* SERD_NULLABLE           stream);
+serd_writer_new(SerdSyntax            syntax,
+                SerdWriterFlags       flags,
+                SerdEnv* SERD_NONNULL env,
+                SerdSink SERD_NONNULL ssink,
+                void* SERD_NULLABLE   stream);
 
 /// Free `writer`
 SERD_API void
diff --git a/src/env.c b/src/env.c
index 78680a0f..8b3970b3 100644
--- a/src/env.c
+++ b/src/env.c
@@ -3,10 +3,10 @@
 
 #include "serd/env.h"
 
+#include "env.h"
 #include "node.h"
 
 #include "serd/node.h"
-#include "serd/uri.h"
 
 #include <stdbool.h>
 #include <stdio.h>
@@ -26,14 +26,11 @@ struct SerdEnvImpl {
 };
 
 SerdEnv*
-serd_env_new(const SerdNode* const base_uri)
+serd_env_new(const SerdStringView base_uri)
 {
   SerdEnv* env = (SerdEnv*)calloc(1, sizeof(struct SerdEnvImpl));
-  if (env && base_uri) {
-    if (serd_env_set_base_uri(env, base_uri)) {
-      free(env);
-      return NULL;
-    }
+  if (env && base_uri.length) {
+    serd_env_set_base_uri(env, base_uri);
   }
 
   return env;
@@ -55,41 +52,39 @@ serd_env_free(SerdEnv* const env)
   free(env);
 }
 
-const SerdNode*
-serd_env_base_uri(const SerdEnv* const env, SerdURIView* const out)
+SerdURIView
+serd_env_base_uri_view(const SerdEnv* const env)
 {
-  if (out) {
-    *out = env->base_uri;
-  }
+  return env->base_uri;
+}
 
-  return env->base_uri_node;
+const SerdNode*
+serd_env_base_uri(const SerdEnv* const env)
+{
+  return env ? env->base_uri_node : NULL;
 }
 
 SerdStatus
-serd_env_set_base_uri(SerdEnv* const env, const SerdNode* const uri)
+serd_env_set_base_uri(SerdEnv* const env, const SerdStringView uri)
 {
-  if (uri && uri->type != SERD_URI) {
-    return SERD_BAD_ARG;
-  }
-
-  if (!uri) {
+  if (!uri.length) {
     serd_node_free(env->base_uri_node);
     env->base_uri_node = NULL;
     env->base_uri      = SERD_URI_NULL;
     return SERD_SUCCESS;
   }
 
+  SerdNode* const old_base_uri = env->base_uri_node;
+
   // Resolve the new base against the current base in case it is relative
   const SerdURIView new_base_uri =
-    serd_resolve_uri(serd_parse_uri(serd_node_string(uri)), env->base_uri);
-
-  SerdNode* const new_base_node = serd_new_parsed_uri(new_base_uri);
+    serd_resolve_uri(serd_parse_uri(uri.data), env->base_uri);
 
   // Replace the current base URI
-  serd_node_free(env->base_uri_node);
-  env->base_uri_node = new_base_node;
+  env->base_uri_node = serd_new_parsed_uri(new_base_uri);
   env->base_uri      = serd_node_uri_view(env->base_uri_node);
 
+  serd_node_free(old_base_uri);
   return SERD_SUCCESS;
 }
 
@@ -110,39 +105,33 @@ serd_env_find(const SerdEnv* const env,
 }
 
 static void
-serd_env_add(SerdEnv* const        env,
-             const SerdNode* const name,
-             const SerdNode* const uri)
+serd_env_add(SerdEnv* const       env,
+             const SerdStringView name,
+             const SerdStringView uri)
 {
-  const char*       name_str = serd_node_string(name);
-  SerdPrefix* const prefix   = serd_env_find(env, name_str, name->length);
+  SerdPrefix* const prefix = serd_env_find(env, name.data, name.length);
   if (prefix) {
-    if (!serd_node_equals(prefix->uri, uri)) {
-      SerdNode* old_prefix_uri = prefix->uri;
-      prefix->uri              = serd_node_copy(uri);
-      serd_node_free(old_prefix_uri);
+    if (!!strcmp(serd_node_string(prefix->uri), uri.data)) {
+      serd_node_free(prefix->uri);
+      prefix->uri = serd_new_uri(uri);
     }
   } else {
     SerdPrefix* const new_prefixes = (SerdPrefix*)realloc(
       env->prefixes, (++env->n_prefixes) * sizeof(SerdPrefix));
     if (new_prefixes) {
       env->prefixes                           = new_prefixes;
-      env->prefixes[env->n_prefixes - 1].name = serd_node_copy(name);
-      env->prefixes[env->n_prefixes - 1].uri  = serd_node_copy(uri);
+      env->prefixes[env->n_prefixes - 1].name = serd_new_string(name);
+      env->prefixes[env->n_prefixes - 1].uri  = serd_new_uri(uri);
     }
   }
 }
 
 SerdStatus
-serd_env_set_prefix(SerdEnv* const        env,
-                    const SerdNode* const name,
-                    const SerdNode* const uri)
+serd_env_set_prefix(SerdEnv* const       env,
+                    const SerdStringView name,
+                    const SerdStringView uri)
 {
-  if (!name || uri->type != SERD_URI) {
-    return SERD_BAD_ARG;
-  }
-
-  if (serd_uri_string_has_scheme(serd_node_string(uri))) {
+  if (serd_uri_string_has_scheme(uri.data)) {
     // Set prefix to absolute URI
     serd_env_add(env, name, uri);
     return SERD_SUCCESS;
@@ -153,32 +142,14 @@ serd_env_set_prefix(SerdEnv* const        env,
   }
 
   // Resolve relative URI and create a new node and URI for it
-  SerdNode* const abs_uri =
-    serd_new_resolved_uri(serd_node_string_view(uri), env->base_uri);
+  SerdNode* const abs_uri = serd_new_resolved_uri(uri, env->base_uri);
 
   // Set prefix to resolved (absolute) URI
-  serd_env_add(env, name, abs_uri);
-
+  serd_env_add(env, name, serd_node_string_view(abs_uri));
   serd_node_free(abs_uri);
-
   return SERD_SUCCESS;
 }
 
-SerdStatus
-serd_env_set_prefix_from_strings(SerdEnv* const    env,
-                                 const char* const name,
-                                 const char* const uri)
-{
-  SerdNode* name_node = serd_new_string(SERD_LITERAL, name);
-  SerdNode* uri_node  = serd_new_string(SERD_URI, uri);
-
-  const SerdStatus st = serd_env_set_prefix(env, name_node, uri_node);
-
-  serd_node_free(name_node);
-  serd_node_free(uri_node);
-  return st;
-}
-
 bool
 serd_env_qualify(const SerdEnv* const   env,
                  const SerdNode* const  uri,
diff --git a/src/env.h b/src/env.h
new file mode 100644
index 00000000..ed3fbfd9
--- /dev/null
+++ b/src/env.h
@@ -0,0 +1,14 @@
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
+
+#ifndef SERD_SRC_ENV_H
+#define SERD_SRC_ENV_H
+
+#include "serd/attributes.h"
+#include "serd/env.h"
+#include "serd/uri.h"
+
+SERD_PURE_FUNC SerdURIView
+serd_env_base_uri_view(const SerdEnv* env);
+
+#endif // SERD_SRC_ENV_H
diff --git a/src/node.c b/src/node.c
index 8edf7fc1..43a4b502 100644
--- a/src/node.c
+++ b/src/node.c
@@ -10,7 +10,6 @@
 #include "serd/attributes.h"
 #include "serd/buffer.h"
 #include "serd/node.h"
-#include "serd/string.h"
 #include "serd/string_view.h"
 #include "serd/uri.h"
 
@@ -36,6 +35,9 @@ static const size_t serd_node_align = 2 * sizeof(uint64_t);
 
 static const SerdNodeFlags meta_mask = (SERD_HAS_DATATYPE | SERD_HAS_LANGUAGE);
 
+static SerdNode*
+serd_new_from_uri(SerdURIView uri, SerdURIView base);
+
 static size_t
 serd_uri_string_length(const SerdURIView* const uri)
 {
@@ -124,68 +126,74 @@ serd_node_set(SerdNode** const dst, const SerdNode* const src)
 }
 
 SerdNode*
-serd_new_string(SerdNodeType type, const char* str)
+serd_new_token(const SerdNodeType type, const SerdStringView str)
 {
-  SerdNodeFlags flags  = 0;
-  const size_t  length = serd_strlen(str, &flags);
+  SerdNodeFlags flags  = 0U;
+  const size_t  length = str.data ? str.length : 0U;
   SerdNode*     node   = serd_node_malloc(length, flags, type);
 
-  memcpy(serd_node_buffer(node), str, length);
-  node->length = length;
+  if (node) {
+    if (str.data) {
+      memcpy(serd_node_buffer(node), str.data, length);
+    }
+
+    node->length = length;
+  }
 
   return node;
 }
 
 SerdNode*
-serd_new_substring(const SerdNodeType type,
-                   const char* const  str,
-                   const size_t       len)
+serd_new_string(const SerdStringView str)
 {
   SerdNodeFlags flags  = 0;
-  const size_t  length = serd_substrlen(str, len, &flags);
-  SerdNode*     node   = serd_node_malloc(length, flags, type);
-  memcpy(serd_node_buffer(node), str, length);
+  const size_t  length = serd_substrlen(str.data, str.length, &flags);
+  SerdNode*     node   = serd_node_malloc(length, flags, SERD_LITERAL);
+
+  memcpy(serd_node_buffer(node), str.data, str.length);
   node->length = length;
+
   return node;
 }
 
 SerdNode*
-serd_new_literal(const char* const str,
-                 const char* const datatype,
-                 const char* const lang)
+serd_new_literal(const SerdStringView str,
+                 const SerdStringView datatype_uri,
+                 const SerdStringView lang)
 {
   SerdNodeFlags flags  = 0;
-  const size_t  length = serd_strlen(str, &flags);
+  const size_t  length = serd_substrlen(str.data, str.length, &flags);
   const size_t  len    = serd_node_pad_size(length);
 
   SerdNode* node = NULL;
-  if (lang) {
-    flags |= SERD_HAS_LANGUAGE;
-    const size_t lang_len  = strlen(lang);
-    const size_t total_len = len + sizeof(SerdNode) + lang_len;
-    node                   = serd_node_malloc(total_len, flags, SERD_LITERAL);
-    memcpy(serd_node_buffer(node), str, length);
+  if (lang.length) {
+    const size_t total_len = len + sizeof(SerdNode) + lang.length;
+
+    node = serd_node_malloc(total_len, flags | SERD_HAS_LANGUAGE, SERD_LITERAL);
     node->length = length;
+    memcpy(serd_node_buffer(node), str.data, length);
 
     SerdNode* lang_node = node + 1 + (len / sizeof(SerdNode));
     lang_node->type     = SERD_LITERAL;
-    lang_node->length   = lang_len;
-    memcpy(serd_node_buffer(lang_node), lang, lang_len);
-  } else if (datatype) {
-    flags |= SERD_HAS_DATATYPE;
-    const size_t datatype_len = strlen(datatype);
-    const size_t total_len    = len + sizeof(SerdNode) + datatype_len;
-    node = serd_node_malloc(total_len, flags, SERD_LITERAL);
-    memcpy(serd_node_buffer(node), str, length);
+    lang_node->length   = lang.length;
+    memcpy(serd_node_buffer(lang_node), lang.data, lang.length);
+
+  } else if (datatype_uri.length) {
+    const size_t total_len = len + sizeof(SerdNode) + datatype_uri.length;
+
+    node = serd_node_malloc(total_len, flags | SERD_HAS_DATATYPE, SERD_LITERAL);
     node->length = length;
+    memcpy(serd_node_buffer(node), str.data, length);
 
     SerdNode* datatype_node = node + 1 + (len / sizeof(SerdNode));
     datatype_node->type     = SERD_URI;
-    datatype_node->length   = datatype_len;
-    memcpy(serd_node_buffer(datatype_node), datatype, datatype_len);
+    datatype_node->length   = datatype_uri.length;
+    memcpy(
+      serd_node_buffer(datatype_node), datatype_uri.data, datatype_uri.length);
+
   } else {
     node = serd_node_malloc(length, flags, SERD_LITERAL);
-    memcpy(serd_node_buffer(node), str, length);
+    memcpy(serd_node_buffer(node), str.data, length);
     node->length = length;
   }
 
@@ -193,6 +201,18 @@ serd_new_literal(const char* const str,
 }
 
 SerdNode*
+serd_new_blank(const SerdStringView str)
+{
+  return serd_new_token(SERD_BLANK, str);
+}
+
+SerdNode*
+serd_new_curie(const SerdStringView str)
+{
+  return serd_new_token(SERD_CURIE, str);
+}
+
+SerdNode*
 serd_node_copy(const SerdNode* node)
 {
   if (!node) {
@@ -235,13 +255,9 @@ serd_node_equals(const SerdNode* const a, const SerdNode* const b)
 }
 
 SerdNode*
-serd_new_uri(const char* const str)
+serd_new_uri(const SerdStringView string)
 {
-  const size_t length = strlen(str);
-  SerdNode*    node   = serd_node_malloc(length, 0, SERD_URI);
-  memcpy(serd_node_buffer(node), str, length);
-  node->length = length;
-  return node;
+  return serd_new_token(SERD_URI, string);
 }
 
 SerdNode*
@@ -334,54 +350,48 @@ is_dir_sep(const char c)
 }
 
 SerdNode*
-serd_new_file_uri(const char* const  path,
-                  const char* const  hostname,
-                  SerdURIView* const out)
-{
-  const size_t path_len     = strlen(path);
-  const size_t hostname_len = hostname ? strlen(hostname) : 0;
-  const bool   is_windows   = is_windows_path(path);
-  size_t       uri_len      = 0;
-  char*        uri          = NULL;
-
-  if (is_dir_sep(path[0]) || is_windows) {
-    uri_len = strlen("file://") + hostname_len + is_windows;
+serd_new_file_uri(const SerdStringView path, const SerdStringView hostname)
+{
+  const bool is_windows = is_windows_path(path.data);
+  size_t     uri_len    = 0;
+  char*      uri        = NULL;
+
+  if (is_dir_sep(path.data[0]) || is_windows) {
+    uri_len = strlen("file://") + hostname.length + is_windows;
     uri     = (char*)calloc(uri_len + 1, 1);
 
     memcpy(uri, "file://", 7);
 
-    if (hostname) {
-      memcpy(uri + 7, hostname, hostname_len + 1);
+    if (hostname.length) {
+      memcpy(uri + 7, hostname.data, hostname.length + 1);
     }
 
     if (is_windows) {
-      uri[7 + hostname_len] = '/';
+      uri[7 + hostname.length] = '/';
     }
   }
 
   SerdBuffer buffer = {uri, uri_len};
-  for (size_t i = 0; i < path_len; ++i) {
-    if (path[i] == '%') {
+  for (size_t i = 0; i < path.length; ++i) {
+    if (path.data[i] == '%') {
       serd_buffer_sink("%%", 2, &buffer);
-    } else if (is_uri_path_char(path[i])) {
-      serd_buffer_sink(path + i, 1, &buffer);
+    } else if (is_uri_path_char(path.data[i])) {
+      serd_buffer_sink(path.data + i, 1, &buffer);
 #ifdef _WIN32
-    } else if (path[i] == '\\') {
+    } else if (path.data[i] == '\\') {
       serd_buffer_sink("/", 1, &buffer);
 #endif
     } else {
       char escape_str[10] = {'%', 0, 0, 0, 0, 0, 0, 0, 0, 0};
-      snprintf(escape_str + 1, sizeof(escape_str) - 1, "%X", (unsigned)path[i]);
+      snprintf(
+        escape_str + 1, sizeof(escape_str) - 1, "%X", (unsigned)path.data[i]);
       serd_buffer_sink(escape_str, 3, &buffer);
     }
   }
 
   const size_t      length = buffer.len;
   const char* const string = serd_buffer_sink_finish(&buffer);
-  SerdNode* const   node   = serd_new_substring(SERD_URI, string, length);
-  if (out) {
-    *out = serd_parse_uri(serd_node_buffer(node));
-  }
+  SerdNode* const   node   = serd_new_string(serd_substring(string, length));
 
   free(buffer.buf);
   return node;
@@ -527,6 +537,13 @@ serd_node_uri_view(const SerdNode* const node)
                                   : SERD_URI_NULL;
 }
 
+SERD_PURE_FUNC static const SerdNode*
+serd_node_meta_node(const SerdNode* node)
+{
+  const size_t len = serd_node_pad_size(node->length);
+  return node + 1 + (len / sizeof(SerdNode));
+}
+
 const SerdNode*
 serd_node_datatype(const SerdNode* const node)
 {
@@ -534,8 +551,7 @@ serd_node_datatype(const SerdNode* const node)
     return NULL;
   }
 
-  const size_t          len      = serd_node_pad_size(node->length);
-  const SerdNode* const datatype = node + 1 + (len / sizeof(SerdNode));
+  const SerdNode* const datatype = serd_node_meta_node(node);
   assert(datatype->type == SERD_URI || datatype->type == SERD_CURIE);
   return datatype;
 }
@@ -547,8 +563,7 @@ serd_node_language(const SerdNode* const node)
     return NULL;
   }
 
-  const size_t          len  = serd_node_pad_size(node->length);
-  const SerdNode* const lang = node + 1 + (len / sizeof(SerdNode));
+  const SerdNode* const lang = serd_node_meta_node(node);
   assert(lang->type == SERD_LITERAL);
   return lang;
 }
diff --git a/src/serdi.c b/src/serdi.c
index 85462532..cdd3a7b1 100644
--- a/src/serdi.c
+++ b/src/serdi.c
@@ -11,6 +11,7 @@
 #include "serd/reader.h"
 #include "serd/sink.h"
 #include "serd/status.h"
+#include "serd/string_view.h"
 #include "serd/syntax.h"
 #include "serd/uri.h"
 #include "serd/version.h"
@@ -331,20 +332,19 @@ main(int argc, char** argv)
   const SerdWriterFlags writer_flags = choose_style(
     input_syntax, output_syntax, ascii, bulk_write, full_uris, lax);
 
-  SerdURIView base_uri = SERD_URI_NULL;
-  SerdNode*   base     = NULL;
+  SerdNode* base = NULL;
   if (a < argc) { // Base URI given on command line
-    base_uri = serd_parse_uri(argv[a]);
-    base     = serd_new_parsed_uri(base_uri);
+    base = serd_new_uri(serd_string((const char*)argv[a]));
   } else if (from_file && in_fd != stdin) { // Use input file URI
-    base = serd_new_file_uri(input, NULL, &base_uri);
+    base = serd_new_file_uri(serd_string(input), serd_empty_string());
   }
 
   FILE* const    out_fd = stdout;
-  SerdEnv* const env    = serd_env_new(base);
+  SerdEnv* const env =
+    serd_env_new(base ? serd_node_string_view(base) : serd_empty_string());
 
-  SerdWriter* const writer = serd_writer_new(
-    output_syntax, writer_flags, env, base, serd_file_sink, out_fd);
+  SerdWriter* const writer =
+    serd_writer_new(output_syntax, writer_flags, env, serd_file_sink, out_fd);
 
   SerdReader* const reader =
     serd_reader_new(input_syntax,
@@ -361,11 +361,14 @@ main(int argc, char** argv)
     serd_writer_set_error_sink(writer, quiet_error_sink, NULL);
   }
 
-  SerdNode* root = root_uri ? serd_new_string(SERD_URI, root_uri) : NULL;
-  serd_writer_set_root_uri(writer, root);
+  if (root_uri) {
+    SerdNode* const root = serd_new_uri(serd_string(root_uri));
+    serd_writer_set_root_uri(writer, root);
+    serd_node_free(root);
+  }
+
   serd_writer_chop_blank_prefix(writer, chop_prefix);
   serd_reader_add_blank_prefix(reader, add_prefix);
-  serd_node_free(root);
 
   SerdStatus st = SERD_SUCCESS;
   if (!from_file) {
diff --git a/src/writer.c b/src/writer.c
index 5aad6d29..cea75aec 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: ISC
 
 #include "byte_sink.h"
+#include "env.h"
 #include "node.h"
 #include "serd_internal.h"
 #include "stack.h"
@@ -759,7 +760,7 @@ write_uri_node(SerdWriter* const writer,
   }
 
   if (!has_scheme && !supports_uriref(writer) &&
-      !serd_env_base_uri(writer->env, NULL)) {
+      !serd_env_base_uri(writer->env)) {
     return w_err(writer,
                  SERD_BAD_ARG,
                  "syntax does not support URI reference <%s>\n",
@@ -768,14 +769,13 @@ write_uri_node(SerdWriter* const writer,
 
   TRY(st, esink("<", 1, writer));
 
-  SerdURIView base_uri = SERD_URI_NULL;
-  if ((writer->flags & SERD_WRITE_RESOLVED) &&
-      serd_env_base_uri(writer->env, &base_uri)) {
-    SerdURIView        uri     = serd_parse_uri(node_str);
-    SerdURIView        abs_uri = serd_resolve_uri(uri, base_uri);
-    bool               rooted  = uri_is_under(&base_uri, &writer->root_uri);
-    const SerdURIView* root    = rooted ? &writer->root_uri : &base_uri;
-    UriSinkContext     ctx     = {writer, SERD_SUCCESS};
+  if ((writer->flags & SERD_WRITE_RESOLVED) && serd_env_base_uri(writer->env)) {
+    const SerdURIView  base_uri = serd_env_base_uri_view(writer->env);
+    SerdURIView        uri      = serd_parse_uri(node_str);
+    SerdURIView        abs_uri  = serd_resolve_uri(uri, base_uri);
+    bool               rooted   = uri_is_under(&base_uri, &writer->root_uri);
+    const SerdURIView* root     = rooted ? &writer->root_uri : &base_uri;
+    UriSinkContext     ctx      = {writer, SERD_SUCCESS};
 
     if (!supports_abbrev(writer) || !uri_is_under(&abs_uri, root)) {
       serd_write_uri(abs_uri, uri_sink, &ctx);
@@ -1126,7 +1126,6 @@ SerdWriter*
 serd_writer_new(SerdSyntax      syntax,
                 SerdWriterFlags flags,
                 SerdEnv*        env,
-                const SerdNode* base_uri,
                 SerdSink        ssink,
                 void*           stream)
 {
@@ -1143,7 +1142,6 @@ serd_writer_new(SerdSyntax      syntax,
   writer->byte_sink  = serd_byte_sink_new(
     ssink, stream, (flags & SERD_WRITE_BULK) ? SERD_PAGE_SIZE : 1);
 
-  serd_env_set_base_uri(writer->env, base_uri);
   return writer;
 }
 
@@ -1174,14 +1172,24 @@ serd_writer_chop_blank_prefix(SerdWriter* writer, const char* prefix)
 SerdStatus
 serd_writer_set_base_uri(SerdWriter* writer, const SerdNode* uri)
 {
-  SerdStatus st = SERD_SUCCESS;
+  if (uri && serd_node_type(uri) != SERD_URI) {
+    return SERD_BAD_ARG;
+  }
+
+  if (serd_node_equals(serd_env_base_uri(writer->env), uri)) {
+    return SERD_SUCCESS;
+  }
 
-  TRY(st, serd_env_set_base_uri(writer->env, uri));
+  const SerdStringView uri_string =
+    uri ? serd_node_string_view(uri) : serd_empty_string();
+
+  SerdStatus st = SERD_SUCCESS;
+  TRY(st, serd_env_set_base_uri(writer->env, uri_string));
 
   if (uri && (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG)) {
     TRY(st, terminate_context(writer));
     TRY(st, esink("@base <", 7, writer));
-    TRY(st, esink(serd_node_string(uri), serd_node_length(uri), writer));
+    TRY(st, esink(uri_string.data, uri_string.length, writer));
     TRY(st, esink(">", 1, writer));
     writer->last_sep = SEP_NODE;
     TRY(st, write_sep(writer, SEP_END_DIRECT));
@@ -1199,7 +1207,7 @@ serd_writer_set_root_uri(SerdWriter* writer, const SerdNode* uri)
 
   if (uri) {
     writer->root_node = serd_node_copy(uri);
-    writer->root_uri  = serd_parse_uri(serd_node_string(writer->root_node));
+    writer->root_uri  = serd_node_uri_view(writer->root_node);
   }
 
   return SERD_SUCCESS;
@@ -1212,7 +1220,9 @@ serd_writer_set_prefix(SerdWriter*     writer,
 {
   SerdStatus st = SERD_SUCCESS;
 
-  TRY(st, serd_env_set_prefix(writer->env, name, uri));
+  TRY(st,
+      serd_env_set_prefix(
+        writer->env, serd_node_string_view(name), serd_node_string_view(uri)));
 
   if (writer->syntax == SERD_TURTLE || writer->syntax == SERD_TRIG) {
     TRY(st, terminate_context(writer));
diff --git a/test/test_env.c b/test/test_env.c
index b1371d16..8dbc24a1 100644
--- a/test/test_env.c
+++ b/test/test_env.c
@@ -24,15 +24,12 @@ count_prefixes(void* handle, const SerdNode* name, const SerdNode* uri)
 static void
 test_env(void)
 {
-  SerdNode* u   = serd_new_string(SERD_URI, "http://example.org/foo");
-  SerdNode* b   = serd_new_string(SERD_CURIE, "invalid");
-  SerdNode* e   = serd_new_string(SERD_URI, "");
-  SerdNode* c   = serd_new_string(SERD_CURIE, "eg.2:b");
-  SerdNode* s   = serd_new_string(SERD_LITERAL, "hello");
-  SerdEnv*  env = serd_env_new(NULL);
-  serd_env_set_prefix_from_strings(env, "eg.2", "http://example.org/");
-
-  assert(!serd_env_new(s));
+  SerdNode* u   = serd_new_uri(serd_string("http://example.org/foo"));
+  SerdNode* b   = serd_new_curie(serd_string("invalid"));
+  SerdNode* e   = serd_new_uri(serd_empty_string());
+  SerdNode* c   = serd_new_curie(serd_string("eg.2:b"));
+  SerdNode* s   = serd_new_string(serd_string("hello"));
+  SerdEnv*  env = serd_env_new(serd_empty_string());
 
   const SerdNode* prefix_node = NULL;
   SerdStringView  prefix      = serd_empty_string();
@@ -42,20 +39,29 @@ test_env(void)
 
   assert(serd_env_expand(env, NULL, &prefix, &suffix) == SERD_BAD_CURIE);
 
-  assert(serd_env_set_prefix_from_strings(env, "eg.3", "rel") == SERD_BAD_ARG);
+  assert(!serd_env_base_uri(env));
+  assert(!serd_env_set_base_uri(env, serd_empty_string()));
+  assert(!serd_env_base_uri(env));
+  assert(!serd_env_base_uri(env));
+
+  serd_env_set_prefix(
+    env, serd_string("eg.2"), serd_string("http://example.org/"));
+
+  assert(serd_env_set_prefix(env, serd_string("eg.3"), serd_string("rel")) ==
+         SERD_BAD_ARG);
 
   assert(!serd_env_expand_node(NULL, u));
   assert(!serd_env_expand_node(env, b));
   assert(!serd_env_expand_node(env, s));
   assert(!serd_env_expand_node(env, e));
 
-  assert(!serd_env_set_base_uri(env, NULL));
+  assert(!serd_env_set_base_uri(env, serd_empty_string()));
 
   SerdNode* xu = serd_env_expand_node(env, u);
   assert(!strcmp(serd_node_string(xu), "http://example.org/foo"));
   serd_node_free(xu);
 
-  SerdNode* badpre  = serd_new_string(SERD_CURIE, "hm:what");
+  SerdNode* badpre  = serd_new_curie(serd_string("hm:what"));
   SerdNode* xbadpre = serd_env_expand_node(env, badpre);
   assert(!xbadpre);
 
@@ -63,34 +69,31 @@ test_env(void)
   assert(!strcmp(serd_node_string(xc), "http://example.org/b"));
   serd_node_free(xc);
 
-  SerdNode* lit = serd_new_string(SERD_LITERAL, "hello");
-  assert(serd_env_set_prefix(env, b, lit));
-
-  SerdNode* blank = serd_new_string(SERD_BLANK, "b1");
+  SerdNode* blank = serd_new_blank(serd_string("b1"));
   assert(!serd_env_expand_node(env, blank));
   serd_node_free(blank);
 
   int n_prefixes = 0;
-  serd_env_set_prefix_from_strings(env, "eg.2", "http://example.org/");
+  serd_env_set_prefix(
+    env, serd_string("eg.2"), serd_string("http://example.org/"));
   serd_env_foreach(env, count_prefixes, &n_prefixes);
   assert(n_prefixes == 1);
 
-  SerdNode* shorter_uri = serd_new_string(SERD_URI, "urn:foo");
+  SerdNode* shorter_uri = serd_new_uri(serd_string("urn:foo"));
   assert(!serd_env_qualify(env, shorter_uri, &prefix_node, &suffix));
 
-  assert(!serd_env_set_base_uri(env, u));
-  assert(serd_node_equals(serd_env_base_uri(env, NULL), u));
+  assert(!serd_env_set_base_uri(env, serd_node_string_view(u)));
+  assert(serd_node_equals(serd_env_base_uri(env), u));
 
   SerdNode* xe = serd_env_expand_node(env, e);
   assert(xe);
   assert(!strcmp(serd_node_string(xe), "http://example.org/foo"));
   serd_node_free(xe);
 
-  assert(!serd_env_set_base_uri(env, NULL));
-  assert(!serd_env_base_uri(env, NULL));
+  assert(!serd_env_set_base_uri(env, serd_empty_string()));
+  assert(!serd_env_base_uri(env));
 
   serd_node_free(shorter_uri);
-  serd_node_free(lit);
   serd_node_free(badpre);
   serd_node_free(s);
   serd_node_free(c);
diff --git a/test/test_node.c b/test/test_node.c
index 1d4d1107..68bdf784 100644
--- a/test/test_node.c
+++ b/test/test_node.c
@@ -6,6 +6,7 @@
 #include "serd/memory.h"
 #include "serd/node.h"
 #include "serd/string.h"
+#include "serd/string_view.h"
 #include "serd/uri.h"
 
 #include <assert.h>
@@ -146,19 +147,22 @@ test_blob_to_node(void)
 static void
 test_node_equals(void)
 {
-  const uint8_t replacement_char_str[] = {0xEF, 0xBF, 0xBD, 0};
-  SerdNode*     lhs =
-    serd_new_string(SERD_LITERAL, (const char*)replacement_char_str);
-  SerdNode* rhs = serd_new_string(SERD_LITERAL, "123");
+  static const uint8_t replacement_char_str[] = {0xEF, 0xBF, 0xBD, 0};
+
+  SerdNode* const lhs =
+    serd_new_string(serd_substring((const char*)replacement_char_str, 3));
+
+  assert(serd_node_equals(lhs, lhs));
+
+  SerdNode* const rhs = serd_new_string(serd_string("123"));
   assert(!serd_node_equals(lhs, rhs));
 
-  SerdNode* qnode = serd_new_string(SERD_CURIE, "foo:bar");
+  SerdNode* const qnode = serd_new_curie(serd_string("foo:bar"));
   assert(!serd_node_equals(lhs, qnode));
-  assert(serd_node_equals(lhs, lhs));
+  serd_node_free(qnode);
 
   assert(!serd_node_copy(NULL));
 
-  serd_node_free(qnode);
   serd_node_free(lhs);
   serd_node_free(rhs);
 }
@@ -166,15 +170,15 @@ test_node_equals(void)
 static void
 test_node_from_string(void)
 {
-  SerdNode* const hello = serd_new_string(SERD_LITERAL, "hello\"");
+  SerdNode* const hello = serd_new_string(serd_string("hello\""));
   assert(serd_node_length(hello) == 6);
   assert(serd_node_flags(hello) == SERD_HAS_QUOTE);
-  assert(!strcmp(serd_node_string(hello), "hello\""));
+  assert(!strncmp(serd_node_string(hello), "hello\"", 6));
   assert(!strcmp(serd_node_string_view(hello).data, "hello\""));
   assert(serd_node_string_view(hello).length == 6);
   serd_node_free(hello);
 
-  SerdNode* const uri = serd_new_string(SERD_URI, "http://example.org/");
+  SerdNode* const uri = serd_new_uri(serd_string("http://example.org/"));
   assert(serd_node_length(uri) == 19);
   assert(!strcmp(serd_node_string(uri), "http://example.org/"));
   assert(serd_node_uri_view(uri).authority.length == 11);
@@ -185,14 +189,11 @@ test_node_from_string(void)
 static void
 test_node_from_substring(void)
 {
-  SerdNode* a_b = serd_new_substring(SERD_LITERAL, "a\"bc", 3);
-  assert(serd_node_length(a_b) == 3 && serd_node_flags(a_b) == SERD_HAS_QUOTE &&
-         !strncmp(serd_node_string(a_b), "a\"b", 3));
-
-  serd_node_free(a_b);
-  a_b = serd_new_substring(SERD_LITERAL, "a\"bc", 10);
-  assert(serd_node_length(a_b) == 4 && serd_node_flags(a_b) == SERD_HAS_QUOTE &&
-         !strncmp(serd_node_string(a_b), "a\"bc", 4));
+  SerdNode* const a_b = serd_new_string(serd_substring("a\"bc", 3));
+  assert(serd_node_length(a_b) == 3);
+  assert(serd_node_flags(a_b) == SERD_HAS_QUOTE);
+  assert(strlen(serd_node_string(a_b)) == 3);
+  assert(!strncmp(serd_node_string(a_b), "a\"b", 3));
   serd_node_free(a_b);
 }
 
@@ -209,14 +210,18 @@ check_copy_equals(const SerdNode* const node)
 static void
 test_literal(void)
 {
-  SerdNode* hello2 = serd_new_literal("hello\"", NULL, NULL);
+  SerdNode* hello2 = serd_new_literal(
+    serd_string("hello\""), serd_empty_string(), serd_empty_string());
+
   assert(serd_node_length(hello2) == 6 &&
          serd_node_flags(hello2) == SERD_HAS_QUOTE &&
          !strcmp(serd_node_string(hello2), "hello\""));
   check_copy_equals(hello2);
   serd_node_free(hello2);
 
-  SerdNode* hello_l = serd_new_literal("hello_l\"", NULL, "en");
+  SerdNode* hello_l = serd_new_literal(
+    serd_string("hello_l\""), serd_empty_string(), serd_string("en"));
+
   assert(serd_node_length(hello_l) == 8);
   assert(!strcmp(serd_node_string(hello_l), "hello_l\""));
   assert(serd_node_flags(hello_l) == (SERD_HAS_QUOTE | SERD_HAS_LANGUAGE));
@@ -227,8 +232,10 @@ test_literal(void)
   check_copy_equals(hello_l);
   serd_node_free(hello_l);
 
-  SerdNode* hello_dt =
-    serd_new_literal("hello_dt\"", "http://example.org/Thing", NULL);
+  SerdNode* hello_dt = serd_new_literal(serd_string("hello_dt\""),
+                                        serd_string("http://example.org/Thing"),
+                                        serd_empty_string());
+
   assert(serd_node_length(hello_dt) == 9);
   assert(!strcmp(serd_node_string(hello_dt), "hello_dt\""));
   assert(serd_node_flags(hello_dt) == (SERD_HAS_QUOTE | SERD_HAS_DATATYPE));
@@ -241,6 +248,16 @@ test_literal(void)
   serd_node_free(hello_dt);
 }
 
+static void
+test_blank(void)
+{
+  SerdNode* blank = serd_new_blank(serd_string("b0"));
+  assert(serd_node_length(blank) == 2);
+  assert(serd_node_flags(blank) == 0);
+  assert(!strcmp(serd_node_string(blank), "b0"));
+  serd_node_free(blank);
+}
+
 int
 main(void)
 {
@@ -252,6 +269,7 @@ main(void)
   test_node_from_string();
   test_node_from_substring();
   test_literal();
+  test_blank();
 
   printf("Success\n");
   return 0;
diff --git a/test/test_reader_writer.c b/test/test_reader_writer.c
index 245f5328..b1121cbc 100644
--- a/test/test_reader_writer.c
+++ b/test/test_reader_writer.c
@@ -13,6 +13,7 @@
 #include "serd/statement.h"
 #include "serd/status.h"
 #include "serd/stream.h"
+#include "serd/string_view.h"
 #include "serd/syntax.h"
 #include "serd/writer.h"
 
@@ -414,9 +415,9 @@ test_write_errors(void)
       ctx.n_written    = 0;
       ctx.error_offset = o;
 
-      SerdEnv* const    env = serd_env_new(NULL);
+      SerdEnv* const    env = serd_env_new(serd_empty_string());
       SerdWriter* const writer =
-        serd_writer_new(syntax, style, env, NULL, faulty_sink, &ctx);
+        serd_writer_new(syntax, style, env, faulty_sink, &ctx);
 
       SerdReader* const reader =
         serd_reader_new(SERD_TRIG,
@@ -444,27 +445,28 @@ static void
 test_writer(const char* const path)
 {
   FILE*    fd  = fopen(path, "wb");
-  SerdEnv* env = serd_env_new(NULL);
+  SerdEnv* env = serd_env_new(serd_empty_string());
   assert(fd);
 
-  SerdWriter* writer =
-    serd_writer_new(SERD_TURTLE, 0, env, NULL, serd_file_sink, fd);
+  SerdWriter* writer = serd_writer_new(SERD_TURTLE, 0, env, serd_file_sink, fd);
   assert(writer);
 
   serd_writer_chop_blank_prefix(writer, "tmp");
   serd_writer_chop_blank_prefix(writer, NULL);
 
-  SerdNode* lit = serd_new_string(SERD_LITERAL, "hello");
+  SerdNode* lit = serd_new_string(serd_string("hello"));
 
   assert(serd_writer_set_base_uri(writer, lit));
   assert(serd_writer_set_prefix(writer, lit, lit));
   assert(serd_writer_end_anon(writer, NULL));
   assert(serd_writer_env(writer) == env);
 
-  uint8_t   buf[] = {0xEF, 0xBF, 0xBD, 0};
-  SerdNode* s     = serd_new_string(SERD_URI, "");
-  SerdNode* p     = serd_new_string(SERD_URI, "http://example.org/pred");
-  SerdNode* o     = serd_new_string(SERD_LITERAL, (char*)buf);
+  static const uint8_t buf[]    = {0xEF, 0xBF, 0xBD, 0};
+  const SerdStringView buf_view = {(const char*)buf, 3};
+
+  SerdNode* s = serd_new_uri(serd_empty_string());
+  SerdNode* p = serd_new_uri(serd_string("http://example.org/pred"));
+  SerdNode* o = serd_new_string(buf_view);
 
   // Write 3 invalid statements (should write nothing)
   const SerdNode* junk[][3] = {{s, o, o}, {o, p, o}, {s, o, p}};
@@ -473,26 +475,33 @@ test_writer(const char* const path)
       writer, 0, NULL, junk[i][0], junk[i][1], junk[i][2]));
   }
 
-  SerdNode*       t         = serd_new_literal((char*)buf, "urn:Type", NULL);
-  SerdNode*       l         = serd_new_literal((char*)buf, NULL, "en");
+  const SerdStringView empty    = serd_empty_string();
+  const SerdStringView urn_Type = serd_string("urn:Type");
+  const SerdStringView en       = serd_string("en");
+
+  SerdNode* const t         = serd_new_literal(buf_view, urn_Type, empty);
+  SerdNode* const l         = serd_new_literal(buf_view, empty, en);
   const SerdNode* good[][3] = {{s, p, o}, {s, p, t}, {s, p, l}};
+
   for (size_t i = 0; i < sizeof(good) / (sizeof(SerdNode*) * 3); ++i) {
     assert(!serd_writer_write_statement(
       writer, 0, NULL, good[i][0], good[i][1], good[i][2]));
   }
 
   // Write statements with bad UTF-8 (should be replaced)
-  const char bad_str[] = {(char)0xFF, (char)0x90, 'h', 'i', 0};
-  SerdNode*  bad_lit   = serd_new_string(SERD_LITERAL, bad_str);
-  SerdNode*  bad_uri   = serd_new_string(SERD_URI, bad_str);
+  const char           bad_str[] = {(char)0xFF, (char)0x90, 'h', 'i', 0};
+  const SerdStringView bad_view  = {(const char*)bad_str, 4};
+  SerdNode*            bad_lit   = serd_new_string(bad_view);
+  SerdNode*            bad_uri   = serd_new_uri(bad_view);
   assert(!serd_writer_write_statement(writer, 0, NULL, s, p, bad_lit));
   assert(!serd_writer_write_statement(writer, 0, NULL, s, p, bad_uri));
-  serd_node_free(bad_lit);
+
   serd_node_free(bad_uri);
+  serd_node_free(bad_lit);
 
   // Write 1 valid statement
   serd_node_free(o);
-  o = serd_new_string(SERD_LITERAL, "hello");
+  o = serd_new_string(serd_string("hello"));
   assert(!serd_writer_write_statement(writer, 0, NULL, s, p, o));
 
   serd_writer_free(writer);
@@ -503,13 +512,13 @@ test_writer(const char* const path)
 
   // Test buffer sink
   SerdBuffer buffer = {NULL, 0};
-  writer =
-    serd_writer_new(SERD_TURTLE, 0, env, NULL, serd_buffer_sink, &buffer);
+  writer = serd_writer_new(SERD_TURTLE, 0, env, serd_buffer_sink, &buffer);
 
-  o = serd_new_string(SERD_URI, "http://example.org/base");
-  assert(!serd_writer_set_base_uri(writer, o));
+  SerdNode* const base = serd_new_uri(serd_string("http://example.org/base"));
 
-  serd_node_free(o);
+  serd_writer_set_base_uri(writer, base);
+
+  serd_node_free(base);
   serd_writer_free(writer);
   char* out = serd_buffer_sink_finish(&buffer);
 
@@ -540,7 +549,7 @@ test_reader(const char* path)
 
   assert(serd_reader_read_chunk(reader) == SERD_FAILURE);
 
-  SerdNode* g = serd_new_string(SERD_URI, "http://example.org/");
+  SerdNode* g = serd_new_uri(serd_string("http://example.org/"));
   serd_reader_set_default_graph(reader, g);
   serd_reader_add_blank_prefix(reader, "tmp");
 
diff --git a/test/test_uri.c b/test/test_uri.c
index 3fe0ebd5..74b732fd 100644
--- a/test/test_uri.c
+++ b/test/test_uri.c
@@ -44,7 +44,8 @@ test_file_uri(const char* const hostname,
     expected_path = path;
   }
 
-  SerdNode*   node         = serd_new_file_uri(path, hostname, 0);
+  SerdNode* node = serd_new_file_uri(serd_string(path), serd_string(hostname));
+
   const char* node_str     = serd_node_string(node);
   char*       out_hostname = NULL;
   char*       out_path     = serd_parse_file_uri(node_str, &out_hostname);
@@ -193,22 +194,21 @@ check_relative_uri(const char* const uri_string,
   assert(base_string);
   assert(expected_string);
 
-  SerdNode* const   uri_node  = serd_new_uri(uri_string);
+  SerdNode* const   uri_node  = serd_new_uri(serd_string(uri_string));
   const SerdURIView uri       = serd_node_uri_view(uri_node);
-  SerdNode* const   base_node = serd_new_uri(base_string);
+  SerdNode* const   base_node = serd_new_uri(serd_string(base_string));
   const SerdURIView base      = serd_node_uri_view(base_node);
 
   SerdNode* result_node = NULL;
   if (!root_string) {
     result_node = serd_new_parsed_uri(serd_relative_uri(uri, base));
   } else {
-    SerdNode* const   root_node = serd_new_uri(root_string);
+    SerdNode* const   root_node = serd_new_uri(serd_string(root_string));
     const SerdURIView root      = serd_node_uri_view(root_node);
 
     result_node = serd_uri_is_within(uri, root)
                     ? serd_new_parsed_uri(serd_relative_uri(uri, base))
-                    : serd_new_uri(uri_string);
-
+                    : serd_new_uri(serd_string(uri_string));
     serd_node_free(root_node);
   }
 
diff --git a/test/test_writer.c b/test/test_writer.c
index 68d9e14e..b15f7fdc 100644
--- a/test/test_writer.c
+++ b/test/test_writer.c
@@ -9,6 +9,7 @@
 #include "serd/node.h"
 #include "serd/statement.h"
 #include "serd/status.h"
+#include "serd/string_view.h"
 #include "serd/syntax.h"
 #include "serd/writer.h"
 
@@ -18,18 +19,46 @@
 #include <string.h>
 
 static void
+test_write_bad_prefix(void)
+{
+  SerdEnv*    env    = serd_env_new(serd_empty_string());
+  SerdBuffer  buffer = {NULL, 0};
+  SerdWriter* writer =
+    serd_writer_new(SERD_TURTLE, 0U, env, serd_buffer_sink, &buffer);
+
+  assert(writer);
+
+  SerdNode* name = serd_new_string(serd_string("eg"));
+  SerdNode* uri  = serd_new_uri(serd_string("rel"));
+
+  assert(serd_writer_set_prefix(writer, name, uri) == SERD_BAD_ARG);
+
+  char* const out = serd_buffer_sink_finish(&buffer);
+
+  assert(!strcmp(out, ""));
+  serd_free(out);
+
+  serd_node_free(uri);
+  serd_node_free(name);
+  serd_writer_free(writer);
+  serd_env_free(env);
+}
+
+static void
 test_write_long_literal(void)
 {
-  SerdEnv*    env    = serd_env_new(NULL);
+  SerdEnv*    env    = serd_env_new(serd_empty_string());
   SerdBuffer  buffer = {NULL, 0};
   SerdWriter* writer =
-    serd_writer_new(SERD_TURTLE, 0U, env, NULL, serd_buffer_sink, &buffer);
+    serd_writer_new(SERD_TURTLE, 0U, env, serd_buffer_sink, &buffer);
 
   assert(writer);
 
-  SerdNode* s = serd_new_string(SERD_URI, "http://example.org/s");
-  SerdNode* p = serd_new_string(SERD_URI, "http://example.org/p");
-  SerdNode* o = serd_new_string(SERD_LITERAL, "hello \"\"\"world\"\"\"!");
+  SerdNode* s = serd_new_uri(serd_string("http://example.org/s"));
+  SerdNode* p = serd_new_uri(serd_string("http://example.org/p"));
+  SerdNode* o = serd_new_literal(serd_string("hello \"\"\"world\"\"\"!"),
+                                 serd_empty_string(),
+                                 serd_empty_string());
 
   assert(!serd_writer_write_statement(writer, 0, NULL, s, p, o));
 
@@ -61,14 +90,13 @@ null_sink(const void* const buf, const size_t len, void* const stream)
 static void
 test_writer_cleanup(void)
 {
-  SerdStatus  st  = SERD_SUCCESS;
-  SerdEnv*    env = serd_env_new(NULL);
-  SerdWriter* writer =
-    serd_writer_new(SERD_TURTLE, 0U, env, NULL, null_sink, NULL);
+  SerdStatus  st     = SERD_SUCCESS;
+  SerdEnv*    env    = serd_env_new(serd_empty_string());
+  SerdWriter* writer = serd_writer_new(SERD_TURTLE, 0U, env, null_sink, NULL);
 
-  SerdNode* s = serd_new_string(SERD_URI, "http://example.org/s");
-  SerdNode* p = serd_new_string(SERD_URI, "http://example.org/p");
-  SerdNode* o = serd_new_string(SERD_BLANK, "http://example.org/o");
+  SerdNode* s = serd_new_uri(serd_string("http://example.org/s"));
+  SerdNode* p = serd_new_uri(serd_string("http://example.org/p"));
+  SerdNode* o = serd_new_blank(serd_string("start"));
 
   st = serd_writer_write_statement(writer, SERD_ANON_O_BEGIN, NULL, s, p, o);
   assert(!st);
@@ -78,7 +106,7 @@ test_writer_cleanup(void)
     char buf[12] = {0};
     snprintf(buf, sizeof(buf), "b%u", i);
 
-    SerdNode* next_o = serd_new_string(SERD_BLANK, buf);
+    SerdNode* next_o = serd_new_blank(serd_string(buf));
 
     st = serd_writer_write_statement(
       writer, SERD_ANON_O_BEGIN, NULL, o, p, next_o);
@@ -89,6 +117,7 @@ test_writer_cleanup(void)
 
   // Finish writing without terminating nodes
   assert(!(st = serd_writer_finish(writer)));
+  assert(!(st = serd_writer_set_base_uri(writer, NULL)));
 
   // Set the base to an empty URI
   assert(!(st = serd_writer_set_base_uri(writer, NULL)));
@@ -108,19 +137,19 @@ test_strict_write(void)
   FILE* const       fd   = fopen(path, "wb");
   assert(fd);
 
-  SerdEnv* const    env    = serd_env_new(NULL);
+  SerdEnv* const    env    = serd_env_new(serd_empty_string());
   SerdWriter* const writer = serd_writer_new(
-    SERD_TURTLE, (SerdWriterFlags)SERD_WRITE_STRICT, env, NULL, null_sink, fd);
+    SERD_TURTLE, (SerdWriterFlags)SERD_WRITE_STRICT, env, null_sink, fd);
 
   assert(writer);
 
   const uint8_t bad_str[] = {0xFF, 0x90, 'h', 'i', 0};
 
-  SerdNode* s = serd_new_string(SERD_URI, "http://example.org/s");
-  SerdNode* p = serd_new_string(SERD_URI, "http://example.org/p");
+  SerdNode* s = serd_new_uri(serd_string("http://example.org/s"));
+  SerdNode* p = serd_new_uri(serd_string("http://example.org/p"));
 
-  SerdNode* bad_lit = serd_new_string(SERD_LITERAL, (const char*)bad_str);
-  SerdNode* bad_uri = serd_new_string(SERD_URI, (const char*)bad_str);
+  SerdNode* bad_lit = serd_new_string(serd_string((const char*)bad_str));
+  SerdNode* bad_uri = serd_new_uri(serd_string((const char*)bad_str));
 
   assert(serd_writer_write_statement(writer, 0, NULL, s, p, bad_lit) ==
          SERD_BAD_TEXT);
@@ -151,14 +180,14 @@ error_sink(const void* const buf, const size_t len, void* const stream)
 static void
 test_write_error(void)
 {
-  SerdEnv* const env    = serd_env_new(NULL);
+  SerdEnv* const env    = serd_env_new(serd_empty_string());
   SerdWriter*    writer = NULL;
   SerdStatus     st     = SERD_SUCCESS;
 
-  SerdNode* u = serd_new_string(SERD_URI, "http://example.com/u");
+  SerdNode* u = serd_new_uri(serd_string("http://example.com/u"));
 
-  writer = serd_writer_new(
-    SERD_TURTLE, (SerdWriterFlags)0, env, NULL, error_sink, NULL);
+  writer =
+    serd_writer_new(SERD_TURTLE, (SerdWriterFlags)0, env, error_sink, NULL);
   assert(writer);
   st = serd_writer_write_statement(writer, 0U, NULL, u, u, u);
   assert(st == SERD_BAD_WRITE);
@@ -171,6 +200,7 @@ test_write_error(void)
 int
 main(void)
 {
+  test_write_bad_prefix();
   test_write_long_literal();
   test_writer_cleanup();
   test_strict_write();