kwtbl.cod

来自「编译原理基础」· COD 代码 · 共 28 行

(* KWTBL keyword table lookup procedure V1.0 6-7-91 AG *)

function kwlookup( kw : String; var code : Integer ) : Boolean;
  (* checks whether kw is in the keyword table; if so, returns the
     corresponding integer code *)
  var m, n, k : integer;
  begin
    (* binary search: *)
    m := 1; n := nkws;
    while m<=n do
      begin
        k := m+(n-m) div 2;
        if kw=kwtbl[k] then
          begin
            kwlookup := true;
            code := kwcod[k];
            exit
          end
        else if kw>kwtbl[k] then
          m := k+1
        else
          n := k-1
      end;
    kwlookup := false
  end(*kwlookup*);