TFPExpressionScanner¶

Class for tokenizing expression strings into parser tokens

Declaration¶

Source position: fpexprpars.pp line 61

type

  TFPExpressionScanner = class(TObject)
    FSource: AnsiString;
    LSource: Integer;
    FPos: Integer;
    FChar: PAnsiChar;
    FToken: AnsiString;
    FTokenType: TTokenType = (ttPlus,ttMinus,ttLessThan,ttLargerThan,ttEqual,ttDiv,
              ttMod,ttMul,ttLeft,ttRight,ttLessThanEqual,
              ttLargerThanEqual,ttunequal,ttNumber,ttString,
              ttIdentifier,ttComma,ttAnd,ttOr,ttXor,ttTrue,ttFalse,
              ttNot,ttif,ttCase,ttPower,ttEOF);
  public
    constructor Create;
    function GetToken : TTokenType;
    property Token: AnsiString; {r}
    property TokenType: TTokenType; {r}
    property Source: AnsiString; {rw}
    property Pos: Integer; {r}
    property CurrentChar: AnsiChar; {r}
  end;

Inheritance¶

Description¶

The TFPExpressionScanner class performs lexical analysis on expression strings, breaking them into tokens that can be consumed by the expression parser. It handles the low-level details of character recognition, string parsing, and token classification.

The scanner recognizes all token types defined in TTokenType including operators, literals, identifiers, keywords, and delimiters.

Properties¶

Member	Visibility	Description
CurrentChar read only	public	The current character being processed
Pos read only	public	Current position in the source string
Source	public	The source expression string to scan
Token read only	public	The text of the current token
TokenType read only	public	The type of the current token

See all Properties

Methods¶

Member	Visibility	Description
Create	public	Create a new expression scanner
GetToken	public	Get the next token from the source expression

See all Methods

Fieldss¶

Member	Visibility	Description
FChar	default
FPos	default
FSource	default
FToken	default
FTokenType	default
LSource	default

See all Fieldss