FSON — a human-friendly superset of JSON

Querying

Dotted-string paths

Paths are keys separated by ., with array elements addressed by [N] suffixes:

"database.host"     "retries[2]"     "servers[0].port"     "matrix[1][2]"

Only ., [ and ] are special, so a key with spaces works ("database.connection timeout"); a key that itself contains . or [ cannot be addressed by a path (an accepted limitation).

A malformed path resolves to nothing — never to an exception.

Typed getters

std::string s = doc.getString ( "database.host", "localhost" );
long long   i = doc.getInteger( "database.port", 5432 );
double      d = doc.getDouble ( "ratio", 1.0 );
bool        b = doc.getBoolean( "verbose", false );

The second argument is the fallback, used when the path is missing or the value has the wrong type. getInteger truncates any number.

Presence vs. value

doc.containsPath( "database.pool" );   // bool
Value* v = doc.findPath( "database.pool" );   // nullptr if missing
Value& r = doc.atPath( "database.pool" );      // throws std::out_of_range

Walking the model

Object& root = doc.getRoot();          // throws if the root is not an object
if( Value* v = root.findPath( "database.port" ) )
  if( Number* n = v->asNumber() )
    std::cout << n->asInteger() << '\n';

as*() casts return nullptr on a type mismatch — no dynamic_cast, no exception. Value::Type plus isObject() / isArray() / isString() / … let you branch first.

The query API addresses members by name (find / at / contains), not by index. To iterate, drop to the member API and skip the disabled ones yourself:

for( std::size_t k = 0; k < root.memberCount(); ++k )
{
  Member const& m = root.getMember( k );
  if( m.isDisabled() ) continue;
  // m.getKey(), m.getValue()
}

Disabled members are invisible

Every query entry point above — paths, getX, contains, find, at, size — skips disabled members. To see them, use the member API (memberCount / getMember) — see Object — member API.

Multi-line values

A |-block string reads back as one value with newlines:

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