& Removal in Expressions

I frequently build expressions for use in xBASE and SQL
statements.  For example:

      do case
      case !empty(this.datefrom) and !empty(this.dateto)
         dateexpwo="(trndtlow>=this.datefrom and
trndthi<=this.dateto)"
         dateexpol=;
          "((trndtlow<this.datefrom and this.datefrom<trndthi) or "+;
          "(trndtlow<this.dateto and this.dateto<trndthi))"
      case !empty(this.datefrom) and empty(this.dateto)
         dateexpwo="(trndtlow>=this.datefrom)"
         dateexpol="(trndtlow<this.datefrom and
this.datefrom<trndthi)"
      case empty(this.datefrom) and !empty(this.dateto)
         dateexpwo="(trndthi<=this.dateto)"
         dateexpol="(trndtlow<this.dateto and this.dateto<trndthi)"
      case empty(this.datefrom) and empty(this.dateto)
         dateexpwo=".t."
         dateexpol=".f."     && Overlap with ends is impossible if no
ends!
         endcase

      . . .

      select . . .
      where;
       wostatus="B" and &dateexpwo and . . .

     Short of writing four SQL selects for the above case, is there
any way to get rid of the & use ("&dateexpwo")?

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:
     I have preferences.
     You have biases.
     He/She has prejudices.