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TJSONInteger

TJSONInteger = class(TJSONNumber)

Example​

procedure ScriptEvent(var Value: variant);
var
  Values: TJSONArray;
  Number: TJSONInteger;
begin
  Values := TJSONArray.Create;
  try
    Number := Values.AddInteger(0);  // Borrowed; Values owns it.
    Number.Value := 5000000000;
    Value := Values.AsString;  // [5000000000]
  finally
    Values.Free;
  end;
end;

Usage​

TJSONInteger represents a mutable signed 64-bit JSON integer with exact decimal output and narrower Integer conversions.

Additional Technical Info​

The native TJSONInteger class stores a signed 64-bit integer; correctly constructed helper/parser nodes have ValueType = jsNumber. Its native TJSONNumber ancestor descends from TJSONValue, is hidden and adds no members.

The PascalScript compiler importer incorrectly registers hidden TJSONNumber directly beneath TObject. A TJSONInteger-typed script expression therefore exposes only Value and the TObject surface, not TJSONValue members such as AsString, AsInt64, AsInteger, IsNull, Clear, CopyFrom or IsEqual. It is not compile-time assignable to TJSONValue.

Direct TJSONInteger.Create consequently resolves through TObject.Create and skips the native JSON value-type initializer. Do not use a directly constructed instance as a JSON tree node. TJSONArray.AddInteger, object helpers and the parser invoke the native constructor correctly. Their returned node is parent-owned and borrowed, as shown in the example.

When native JSON code serializes a correctly initialized node—or it is reached through a base-typed TJSONValue reference—AsString uses IntToStr and emits a culture-independent signed decimal representation. Native/base-typed AsString assignment uses Delphi StrToInt64; invalid or out-of-range text raises EConvertError. The converter also accepts some Delphi integer notations outside JSON grammar, then normalizes the stored value to decimal. These conversion members are not exposed through a TJSONInteger-typed script expression.

The class can hold -9223372036854775808 through 9223372036854775807. The generated array AddInteger entry accepts only a 32-bit Integer, but its returned TJSONInteger.Value can subsequently be assigned across the full Int64 range. Native/base-typed AsInteger is a separate 32-bit conversion and raises when the stored decimal value does not fit. Through the correctly registered TJSONInteger script type, Value is the full-range accessor.

Many non-Pascal JSON consumers represent every number as IEEE 754 binary64. RFC 8259 identifies only integers between -(2^53)+1 and (2^53)-1 as reliably interoperable without loss. Preserve larger identifiers as strings when the receiver cannot guarantee Int64 parsing.

The Deltics reader routes a token containing no period to this class. Exponent-only JSON such as 1e3 is therefore sent to StrToInt64 and fails rather than becoming a Double.

Null and base-typed behavior​

Native Clear, or a call through a TJSONValue-typed reference, marks a correctly initialized node null without zeroing its retained Value. Objects serialize the state as null; arrays have a defect that receives blank AsString for this jsNumber and emits an empty token. On the base script type, NotNull is incorrectly bound to IsNull and returns the same value.

Native TJSONInteger.CopyFrom assumes another exact TJSONInteger without a runtime type guard. Native IsEqual compares type, name and AsString, ignores the null flag and can equate cleared integers with different retained values. Neither member is exposed through a TJSONInteger-typed script expression because of the hidden-ancestor registration defect.

External references

Created 2026-07-20