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TokenSymbolIs

function TokenSymbolIs(S: string): Boolean;

Example​

procedure HandleKeyword(Parser: TParser);
begin
  if Parser = nil then Exit;

  if Parser.TokenSymbolIs('inherited') then
    Parser.NextToken;
end;

Usage​

TokenSymbolIs tests whether the current token is an identifier equal to supplied text under Velox's case-insensitive comparison.

Additional Technical Info​

TokenSymbolIs returns true only when the current Token is toSymbol and its TokenString compares equal to S using Delphi SameText. The comparison is case-insensitive; the original token spelling is not changed.

If the current token is a number, string, punctuation or EOF, the result is false. The method does not raise for that kind mismatch. Use it for optional keywords and grammar branches; use CheckTokenSymbol when a particular symbol is mandatory and a mismatch should raise.

The test does not call NextToken, consume the symbol or change the source position. After a true result, the caller must advance explicitly. Repeating the call with the same argument returns the same result until another operation changes parser state.

S is compared as a Unicode String after parser decoding. Non-ASCII identifier availability depends on the source encoding and the installed Delphi character-category logic. Do not use this method as a locale-independent security normalization or as proof that a named Velox object/component exists; it is only a lexical comparison.

An empty S returns false for every normal symbol because a symbol token always has a nonempty identifier start.

The example is source-reviewed only; no token comparison was executed.

External references

Created 2026-07-15