Add serd_node_from_syntax() and serd_node_to_syntax()

2 files changed, 85 insertions, 0 deletions

diff --git a/include/serd/node_syntax.h b/include/serd/node_syntax.h
new file mode 100644
index 00000000..7529c954
--- /dev/null
+++ b/include/serd/node_syntax.h
@@ -0,0 +1,84 @@
+// Copyright 2011-2022 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
+
+#ifndef SERD_NODE_SYNTAX_H
+#define SERD_NODE_SYNTAX_H
+
+#include "serd/attributes.h"
+#include "serd/env.h"
+#include "serd/memory.h"
+#include "serd/node.h"
+#include "serd/syntax.h"
+#include "zix/attributes.h"
+
+SERD_BEGIN_DECLS
+
+/**
+   @defgroup serd_node_syntax Node Syntax
+   @ingroup serd_reading_writing
+   @{
+*/
+
+/**
+   Create a node from a string representation in `syntax`.
+
+   The string should be a node as if written as an object in the given syntax,
+   without any extra quoting or punctuation, which is the format returned by
+   serd_node_to_syntax().  These two functions, when used with #SERD_TURTLE,
+   can be used to round-trip any node to a string and back.
+
+   @param allocator Allocator used for the returned node, and any temporary
+   objects if `env` is null.
+
+   @param str String representation of a node.
+
+   @param syntax Syntax to use.  Should be either SERD_TURTLE or SERD_NTRIPLES
+   (the others are redundant).  Note that namespaced (CURIE) nodes and relative
+   URIs can not be expressed in NTriples.
+
+   @param env Environment of `str`.  This must define any abbreviations needed
+   to parse the string.
+
+   @return A newly allocated node that must be freed with serd_node_free()
+   using the world allocator.
+*/
+SERD_API SerdNode* ZIX_ALLOCATED
+serd_node_from_syntax(SerdAllocator* ZIX_NULLABLE allocator,
+                      const char* ZIX_NONNULL     str,
+                      SerdSyntax                  syntax,
+                      SerdEnv* ZIX_NULLABLE       env);
+
+/**
+   Return a string representation of `node` in `syntax`.
+
+   The returned string represents that node as if written as an object in the
+   given syntax, without any extra quoting or punctuation.
+
+   @param allocator Allocator used for the returned node, and any temporary
+   objects if `env` is null.
+
+   @param node Node to write as a string.
+
+   @param syntax Syntax to use.  Should be either SERD_TURTLE or SERD_NTRIPLES
+   (the others are redundant).  Note that namespaced (CURIE) nodes and relative
+   URIs can not be expressed in NTriples.
+
+   @param env Environment for the output string.  This can be used to
+   abbreviate things nicely by setting namespace prefixes.
+
+   @return A newly allocated string that must be freed with serd_free() using
+   the world allocator.
+*/
+SERD_API char* ZIX_ALLOCATED
+serd_node_to_syntax(SerdAllocator* ZIX_NULLABLE allocator,
+                    const SerdNode* ZIX_NONNULL node,
+                    SerdSyntax                  syntax,
+                    const SerdEnv* ZIX_NULLABLE env);
+
+/**
+   @}
+*/
+
+SERD_END_DECLS
+
+#endif // SERD_NODE_SYNTAX_H
diff --git a/include/serd/serd.h b/include/serd/serd.h
index 4f1d97b5..f874a0cc 100644
--- a/include/serd/serd.h
+++ b/include/serd/serd.h
@@ -81,6 +81,7 @@
 */
 
 #include "serd/input_stream.h"
+#include "serd/node_syntax.h"
 #include "serd/output_stream.h"
 #include "serd/reader.h"
 #include "serd/stream.h"