JSON pointer: Difference between revisions
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Error: bad/pointer does not exist: ErrorException("Non-empty JSON pointers must begin with /")
</pre>
=={{header|Perl}}==
<syntaxhighlight lang="perl">
use strict;
use warnings;
use JSON;
# Sample JSON document
my $json_text = '{
"wiki": {
"links": [
"https://rosettacode.org/wiki/Rosetta_Code",
"https://discord.com/channels/1011262808001880065"
]
},
"": "Rosetta",
" ": "Code",
"g/h": "chrestomathy",
"i~j": "site",
"abc": ["is", "a"],
"def": { "": "programming" }
}';
# Decode the JSON document
my $document = decode_json($json_text);
# Sample JSON Pointers with expected result
my @pointers = (
"", # Entire document
"/", # "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"
"/wiki/links/2", # Error condition
"/wiki/name", # Error condition
"/no/such/thing", # Error condition
"bad/pointer" # Error condition
);
# Function to evaluate a JSON Pointer
sub evaluate_pointer {
my ($document, $pointer) = @_;
# An empty pointer means the whole document
return $document if($pointer eq '');
# check for valid pointer starting with forward slash
return "Error: Non-empty JSON pointers must begin with /" if($pointer !~ /^\//);
# Initialize the current node to the document root
my $current_node = $document;
# Split the pointer into tokens
my @tokens = split '/', $pointer;
if(scalar @tokens < 1) {
# Empty token should be a key in the hash
if (exists $current_node->{''}) {
$current_node = $current_node->{''};
} else {
return "Error: Key '' (empty token) not found.";
}
}
# Process each token
for my $token (@tokens) {
next if($token eq ''); # Skip the empty token from the leading slash
# Decode the token
$token =~ s/~1/\//g;
$token =~ s/~0/~/g;
# Check the current node type
if (ref($current_node) eq 'ARRAY') {
# Token should be an array index
if ($token =~ /^\d+$/ && $token < @$current_node) {
$current_node = $current_node->[$token];
} else {
return "Error: Invalid array index or out of range.";
}
} elsif (ref($current_node) eq 'HASH') {
# Token should be a key in the hash
if (exists $current_node->{$token}) {
$current_node = $current_node->{$token};
} else {
return "Error: Key '$token' not found.";
}
} else {
return "Error: Current node is not an array or object.";
}
}
return $current_node;
}
# Evaluate each pointer and print the result
foreach my $pointer (@pointers) {
my $result = evaluate_pointer($document, $pointer);
print "Pointer: \"$pointer\"\n";
if (ref($result) eq 'HASH' || ref($result) eq 'ARRAY') {
print "Result: " . encode_json($result) . "\n";
} else {
print "Result: $result\n";
}
print "\n";
}
</syntaxhighlight>
=={{header|Phix}}==
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