DataMuseum.dk

top - download

    Length: 1792 (0x700)
    Types: TextFile
    Names: »B«

└─⟦a7d1ea751⟧ Bits:30000550 8mm tape, Rational 1000, !users!projects 94_04_11
    └─ ⟦129cab021⟧ »DATA« 
        └─⟦this⟧ 

TextFile

with Lex;
with Object;
with More_Unary;
with Primary;
package body Unary is
    type Node_Structure is
        record
            Rule : Natural range 0 .. 1 := 0;
            Prim : Primary.Node := Primary.Empty_Node;
            More : More_Unary.Node := More_Unary.Empty_Node;

        end record;

    procedure Parse (N : in out Node; Error : out Boolean) is
        Failed : Boolean := False;

    begin
        N := new Node_Structure;
        if Primary.Is_First (Lex.Get_Token) then
            N.Rule := 0;
            Primary.Parse (N.Prim, Failed);
            if not Failed and Lex.Token'Pos (Lex.Get_Token) =
                                 Lex.Token'Pos (Lex.Identifier) then
                N.Rule := 1;
                More_Unary.Parse (N.More, Failed);
            end if;
        end if;


        Error := Failed;
    end Parse;
    procedure Unparse (N : in out Node) is
    begin
        case N.Rule is
            when 0 =>
                Primary.Unparse (N.Prim);
            when 1 =>
                Primary.Unparse (N.Prim);
                More_Unary.Unparse (N.More);
        end case;
    end Unparse;

    function Is_First (T : Lex.Token) return Boolean is
        use Lex;
    begin
        return Primary.Is_First (T);
    end Is_First;
    function Interpret (N : Node;
                        Inherited : Object.Reference := Object.Void_Reference)
                       return Object.Reference is
        Result : Object.Reference;
    begin
        case N.Rule is
            when 0 =>
                Result := Primary.Interpret (N.Prim);
            when 1 =>
                Result := Primary.Interpret (N.Prim);
                Result := More_Unary.Interpret (N.More, Result);
        end case;
        return Result;
    end Interpret;
end Unary;