uast.pas

{$mode delphi}
unit uAST; // abstract syntax tree for simple interpreter
interface uses classes, sysutils, variants;

  type 
    TSyntax = variant;
    TExpr = variant;
    TBoolExpr = variant;
    TStmt = variant;
    TIfStmt = variant;
    TWhileStmt = variant;
    TWriteStmt = variant;
    TAssignStmt = variant;

  function NewSyntax() : TSyntax;
  function NewExpr() : TExpr;
  function NewBoolExpr() : TBoolExpr;
  function NewStmt() : TStmt;
  function NewIfStmt(condition: TBoolExpr; thenPart: TStmt; elsePart: TStmt) : TIfStmt;
  function NewWhileStmt(condition: TBoolExpr; body: TStmt) : TWhileStmt;
  function NewWriteStmt() : TWriteStmt;
  function NewAssignStmt() : TAssignStmt;

implementation

  function NewSyntax() : TSyntax;
    begin result := null end;

  function NewExpr() : TExpr;
    begin result := null end;

  function NewBoolExpr() : TBoolExpr;
    begin result := null end;

  function NewStmt() : TStmt;
    begin result := null end;

  function NewIfStmt(condition: TBoolExpr; thenPart: TStmt; elsePart: TStmt) : TIfStmt;
    begin result := null end;

  function NewWhileStmt(condition: TBoolExpr; body: TStmt) : TWhileStmt;
    begin result := null end;

  function NewWriteStmt() : TWriteStmt;
    begin result := null end;

  function NewAssignStmt() : TAssignStmt;
    begin result := null end;

end.