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Basic JData Examples

1. Constants and scalars
2. Strings
3. Structures

1. Constants and scalars

Numerical values are directly supported by either JSON or UBJSON specifications. A numerical value is typically unchanged when converting to the JData annotation. When storing as files, they are directly stored in the JSON/UBJSON numerical value forms. For example

Native data text-JData/JSON form binary-JData(UBJSON) 
a=3
 => 
{"a":3}
 
[{][U][1][a][U][3][}]

Similar for a floating point number

Native data text-JData/JSON form binary-JData(UBJSON) † 
a=3.14159
 => 
{"a":3.14159}
 
[{][U][1][a][D][3.15169][}]
† In the case of the binary-JData, the type marker of the floating point number, here [D] must match the native data's type.

There are a few special constants, namely "NaN", "Infinity" and "-Infinity"

Native data text-JData/JSON form † 
a=nan
 => 
{"a":"_NaN_"}
[{][U][1][a][D][nan][}]
a=inf
 => 
{"a":"_Inf_"}
[{][U][1][a][D][inf][}]
a=-inf
 => 
{"a":"-_Inf_"}
[{][U][1][D][-inf][}]

Three special constants are directly supported by the JSON/UBJSON specifications, these constants are logical "True", logical "False" and "Null", they are stored as

Native data text-JData/JSON form binary-JData(UBJSON) 
a=true
 => 
{"a":true}
 
[{][U][1][a][T][}]
a=false
 => 
{"a":false}
 
[{][U][1][a][F][}]
a=null
 => 
{"a":null}
 
[{][U][1][a][N][}]

2. Strings

Strings are natively supported in both JSON and UBJSON, therefore, when converting to the JData annotations, they are mostly unchanged. For JSON strings, 9 special characters can be escaped to represent control sequences (

\",\\,\/,\b,\f,\n,\r,\t,\uXXXX
). For example

Native data text-JData/JSON form † binary-JData(UBJSON) 
a="JData will prevail"
 => 
{"a":"JData will prevail"}
[{][U][1][a][S][U][18][JData will prevail][}]
a="Tabs\tNewlines\n"
 => 
{"a":"Tabs\tNewlines\n"}
[{][U][1][a][S][U][14][Tabs\tNewlines\n][}]
a="中文UTF-8格式"
 => 
{"a":"中文UTF-8格式"}
[{][U][1][a][S][U][17][中文UTF-8格式][}]

We want to mention that in JData, "non-strict" JSON string mode is allowed: that means one can store ASCII values 0-31 as part of the string without escaping.

3. Structures

Hierarchical structures are often needed when representing metadata or simple lists with named-members. Because "structure" data-type can be directly mapped to the "object" construct in JSON and UBJSON, therefore, they do not need to be converted when using the JData annotation.

Native data text-JData/JSON form † binary-JData(UBJSON)

a=struct(
'i1',1,
'f1',2.0,
's1':"string"
)

 =>

{"a":{
"i1":1,
"f1":2.0,
"s1":"string"
}}

[{][U][1][a][S][U][18][JData will prevail][}]
a="Tabs\tNewlines\n"
 => 
{"a":"Tabs\tNewlines\n"}
[{][U][1][a][S][U][14][Tabs\tNewlines\n][}]
a="中文UTF-8格式"
 => 
{"a":"中文UTF-8格式"}
[{][U][1][a][S][U][17][中文UTF-8格式][}]
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