diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 36 |
1 files changed, 15 insertions, 21 deletions
@@ -9509,28 +9509,22 @@ computes a sublist of consisting of elements 1 through 2 (counting from zero). -Restrictions: - -The notation must be enclosed in a list. For instance -.code a..b -is not, by itself, an -expression, but -.code (a..b) -is. This is important if Lisp data is being parsed from -a string or stream using the read function. If the data -.str "a..b" -is parsed, the symbol -.code a -will be extracted, leaving -.strn ..a , -which, if parsed, -produces a syntax error since it consists of a "dotdot" token followed by -a symbol, which is not valid syntax. - -The notation cannot occur in the dot position; that is, the syntax +Note that if this notation is used in the dot position of an improper +list, the transformation still applies. That is, the syntax .code (a . b .. c) -is invalid. The dotdot operator can only be used between the non-dot-position -elements of a list. +is valid and produces the object +.code (a . (cons b c)) +which is another way of writing +.codn (a cons b c) . + +The notation's +.code .. +operator associates right to left, so that +.code a..b..c +denotes +.code (cons a (cons b c)) +or +.codn (a b . c) . .NP* The DWIM Brackets \*(TL has a square bracket notation. The syntax |