For example, suppose that in implementation A, the features spice and perq are present, but the feature lispm is not present; in implementation B, the feature lispm is present, but the features spice and perq are not present; and in implementation C, none of the features spice, lispm, or perq are present. Figure 24--1 shows some sample expressions, and how they would be read_2 in these implementations.
(cons #+spice "Spice" #-spice "Lispm" x) in implementation A ... (CONS "Spice" X) in implementation B ... (CONS "Lispm" X) in implementation C ... (CONS "Lispm" X) (cons #+spice "Spice" #+LispM "Lispm" x) in implementation A ... (CONS "Spice" X) in implementation B ... (CONS "Lispm" X) in implementation C ... (CONS X) (setq a '(1 2 #+perq 43 #+(not perq) 27)) in implementation A ... (SETQ A '(1 2 43)) in implementation B ... (SETQ A '(1 2 27)) in implementation C ... (SETQ A '(1 2 27)) (let ((a 3) #+(or spice lispm) (b 3)) (foo a)) in implementation A ... (LET ((A 3) (B 3)) (FOO A)) in implementation B ... (LET ((A 3) (B 3)) (FOO A)) in implementation C ... (LET ((A 3)) (FOO A)) (cons #+Lispm "#+Spice" #+Spice "foo" #-(or Lispm Spice) 7 x) in implementation A ... (CONS "foo" X) in implementation B ... (CONS "#+Spice" X) in implementation C ... (CONS 7 X)
Figure 24--1: Features examples
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