JSON pointer: Difference between revisions
→{{header|Julia}}
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error: "bad/pointer" pointers must start with a slash or be the empty string
</pre>
=={{header|Julia}}==
{{trans|JavaScript}}
<syntaxhighlight lang="julia">""" rosettacode.org/wiki/JSON_pointer """
struct JSON_Pointer
tokens::Vector{String}
end
JSON_Pointer(s::AbstractString) = JSON_Pointer(jp_parse(s))
resolve(p::JSON_Pointer, data) = reduce(getitem, p.tokens, init=data)
function jp_unencode_join(p::JSON_Pointer)
isempty(p.tokens) && return ""
return "/" * mapreduce(x -> replace(replace(x, "~" => "~0"), "/" => "~1"),
(s1, s2) -> s1 * "/" * s2, p.tokens)
end
Base.print(io::IO, p::JSON_Pointer) = print(io, jp_unencode_join(p))
function jp_parse(s::AbstractString)
if isempty(s)
return String[]
elseif s[begin] != '/'
error("Non-empty JSON pointers must begin with /")
else
return map(x -> replace(replace(x, "~1" => "/"), "~0" => "~"),
split(s, "/"))[begin+1:end]
end
end
"""
NOTE:
- to keep with the JavaScript convention, arrays are 0-based
- string primitives "have own" indices and `length`.
- Arrays have a `length` property.
- A property might exist with the value `undefined`.
- obj[1] is equivalent to obj["1"].
"""
getitem(obj::Vector, token::Integer) = obj[token+1]
getitem(obj::Vector, token::AbstractString) = obj[parse(Int, token)+1]
getitem(obj::Dict, token) = obj[token]
const doc = Dict(
"wiki" => Dict(
"links" => [
"https://rosettacode.org/wiki/Rosetta_Code",
"https://discord.com/channels/1011262808001880065",
],
),
"" => "Rosetta",
" " => "Code",
"g/h" => "chrestomathy",
"i~j" => "site",
"abc" => ["is", "a"],
"def" => Dict("" => "programming"),
)
const examples = [
"",
"/",
"/ ",
"/abc",
"/def/",
"/g~1h",
"/i~0j",
"/wiki/links/0",
"/wiki/links/1",
"/wiki/links/2",
"/wiki/name",
"/no/such/thing",
"bad/pointer",
]
for ex in examples
try
pointer = JSON_Pointer(ex)
result = resolve(pointer, doc)
println("{$ex} -> {$result}")
catch y
println("Error: $ex does not exist: $y")
end
end
</syntaxhighlight>{{out}}
<pre>
{} -> {Dict{String, Any}("abc" => ["is", "a"], "wiki" => Dict("links" => ["https://rosettacode.org/wiki/Rosetta_Code", "https://discord.com/channels/1011262808001880065"]), " " => "Code", "i~j" => "site", "def" => Dict(""
=> "programming"), "" => "Rosetta", "g/h" => "chrestomathy")}
{/} -> {Rosetta}
{/ } -> {Code}
{/abc} -> {["is", "a"]}
{/def/} -> {programming}
{/g~1h} -> {chrestomathy}
{/i~0j} -> {site}
{/wiki/links/0} -> {https://rosettacode.org/wiki/Rosetta_Code}
{/wiki/links/1} -> {https://discord.com/channels/1011262808001880065}
Error: /wiki/links/2 does not exist: BoundsError(["https://rosettacode.org/wiki/Rosetta_Code", "https://discord.com/channels/1011262808001880065"], (3,))
Error: /wiki/name does not exist: KeyError("name")
Error: /no/such/thing does not exist: KeyError("no")
Error: bad/pointer does not exist: ErrorException("Non-empty JSON pointers must begin with /")
</pre>
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