128 lines
2.1 KiB
Plaintext
128 lines
2.1 KiB
Plaintext
.TH JSON 2
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.SH NAME
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jsonparse,
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jsonfree,
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jsonbyname,
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jsonstr
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\- JSON parser
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.SH SYNOPSIS
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.\" .ta 0.75i 1.5i 2.25i 3i 3.75i 4.5i
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.ta 0.7i +0.7i +0.7i +0.7i +0.7i +0.7i +0.7i
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.EX
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#include <u.h>
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#include <libc.h>
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#include <json.h>
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enum {
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JSONNull,
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JSONBool,
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JSONNumber,
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JSONString,
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JSONArray,
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JSONObject,
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};
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typedef struct JSONEl JSONEl;
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struct JSONEl {
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char *name;
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JSON *val;
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JSONEl *next;
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};
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typedef struct JSON JSON;
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struct JSON
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{
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int t;
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union {
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double n;
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char *s;
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JSONEl *first;
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};
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};
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JSON* jsonparse(char *s);
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void jsonfree(JSON *j);
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JSON* jsonbyname(JSON *j, char *s);
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char* jsonstr(JSON *j);
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int JSONfmt(Fmt *f)
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void JSONfmtinstall(void);
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.EE
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.SH DESCRIPTION
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The
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.B JSON
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structure represents a variant json value. The variant type
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is stored in the
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.I t
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member of the structure. String values use
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.BR s ,
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booleans and numbers use the
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.B n
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members in the structure.
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Arrays and objects (dictionaries) are represented by
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a singly-linked list of
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.B JSONEl
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structures referred to from the
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.B first
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pointer in the
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.B JSON
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structure.
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Each
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.B JSONEl
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has a
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.B val
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pointer to the associated value and a
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.B next
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pointer to the next element in the array or object.
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Dictionary objects have the
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.B name
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member set to the key of the association.
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.P
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A json object is parsed by calling
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.I jsonparse
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with a
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.B UTF-8
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string of the json encoded data. On success, a non-nil pointer to a
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newly allocated
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.B JSON
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structure is returned.
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To free the parsed objects,
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.I jsonfree
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has to be called.
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.P
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The
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.I jsonbyname
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function returns the associated value of a dictionary item.
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.P
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The function
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.I jsonstr
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returns the string value of a json object or
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.B nil
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for any other object type.
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.P
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.I JSONfmt
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is a
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.IR print (2)
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formatting routine that prints a well-formatted JSON structure.
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It can be installed by hand but
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.I JSONfmtinstall
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installs it under the standard format character J. The header
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.B <json.h>
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contains a #pragma statement so the compiler can
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type-check uses of
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.B %J
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in
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.IR print (2)
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format strings.
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.SH SOURCE
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.B /sys/src/libjson
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.SH DIAGNOSTICS
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The functions
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.I jsonparse,
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.I jsonbyname
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and
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.I jsonstr
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return
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.B nil
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on error and set an error string (see
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.IR errstr (2)).
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