collecting terms



Dear Maxima forum

I am looking for a command that collects all the terms
of a polynomial w.r.t. a variable, i.e. it writes the polynomial
as a sum of monomials with increasing/decreasing powers of
a given variable.
Is there one?

In the attempt to find such command I tried
expandwrt, which unfortunately does something else.

expandwrt in my case also produces the
following warning/error message:

Given

t :  (x+1)^4 + a*(x+1)^2+b*(x+1)+c;

Then
expandwrt(t,x)

produces:

; In: LAMBDA (FILE &AUX *LOAD-VERBOSE* TEM TRIED)

;   (LET (# #) (DECLARE #) (SETQ TEM #) (AND TEM #))
; ==>
;   (COMMON-LISP:LET (# #)
;     (DECLARE #)
;     (SETQ TEM #)
;     (AND TEM #))
; Note: Variable IN defined but never used.
;
;   #'(LAMBDA (FILE &AUX *LOAD-VERBOSE* TEM TRIED) (BLOCK $ALOAD_MAC #))
; Note: Variable TRIED defined but never used.
; Warning - you are redefining the MACSYMA function INTERSECTION

followed by the output.


  Regards

   Fabrizio Caruso