Clarify the documentation

[jansson.git] / doc / apiref.rst

diff --git a/doc/apiref.rst b/doc/apiref.rst
index ebe00ea..2c6cf3b 100644 (file)
--- a/doc/apiref.rst
+++ b/doc/apiref.rst
@@ -154,9 +154,31 @@ Normally, all functions accepting a JSON value as an argument will
 manage the reference, i.e. increase and decrease the reference count
 as needed. However, some functions **steal** the reference, i.e. they
 have the same result as if the user called :cfunc:`json_decref()` on
-the argument right after calling the function. These are usually
-convenience functions for adding new references to containers and not
-to worry about the reference count.
+the argument right after calling the function. These functions are
+suffixed with ``_new`` or have ``_new_`` somewhere in their name.
+
+For example, the following code creates a new JSON array and appends
+an integer to it::
+
+  json_t *array, *integer;
+
+  array = json_array();
+  integer = json_integer(42);
+
+  json_array_append(array, integer);
+  json_decref(integer);
+
+Note how the caller has to release the reference to the integer value
+by calling :cfunc:`json_decref()`. By using a reference stealing
+function :cfunc:`json_array_append_new()` instead of
+:cfunc:`json_array_append()`, the code becomes much simpler::
+
+  json_t *array = json_array();
+  json_array_append_new(array, json_integer(42));
+
+In this case, the user doesn't have to explicitly release the
+reference to the integer value, as :cfunc:`json_array_append_new()`
+steals the reference when appending the value to the array.
 
 In the following sections it is clearly documented whether a function
 will return a new or borrowed reference or steal a reference to its
@@ -222,6 +244,12 @@ returns the same value each time.
 String
 ======
 
+Jansson uses UTF-8 as the character encoding. All JSON strings must be
+valid UTF-8 (or ASCII, as it's a subset of UTF-8). Normal null
+terminated C strings are used, so JSON strings may not contain
+embedded null characters. All other Unicode codepoints U+0001 through
+U+10FFFF are allowed.
+
 .. cfunction:: json_t *json_string(const char *value)
 
    .. refcounting:: new
@@ -265,6 +293,12 @@ String
 Number
 ======
 
+The JSON specification only contains one numeric type, "number". The C
+programming language has distinct types for integer and floating-point
+numbers, so for practical reasons Jansson also has distinct types for
+the two. They are called "integer" and "real", respectively. For more
+information, see :ref:`rfc-conformance`.
+
 .. cfunction:: json_t *json_integer(int value)
 
    .. refcounting:: new
@@ -634,10 +668,12 @@ This sections describes the functions that can be used to decode JSON
 text to the Jansson representation of JSON data. The JSON
 specification requires that a JSON text is either a serialized array
 or object, and this requirement is also enforced with the following
-functions.
+functions. In other words, the top level value in the JSON text being
+decoded must be either array or object.
 
-The only supported character encoding is UTF-8 (which ASCII is a
-subset of).
+See :ref:`rfc-conformance` for a discussion on Jansson's conformance
+to the JSON specification. It explains many design decisions that
+affect especially the behavior of the decoder.
 
 .. ctype:: json_error_t
 
@@ -722,7 +758,8 @@ only if they are exactly the same value, but also if they have equal
   values are equal. An integer value is never equal to a real value,
   though.
 
-* Two strings are equal if their contained UTF-8 strings are equal.
+* Two strings are equal if their contained UTF-8 strings are equal,
+  byte by byte. Unicode comparison algorithms are not implemented.
 
 * Two arrays are equal if they have the same number of elements and
   each element in the first array is equal to the corresponding