[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Purpose of dash # in elisp
From: |
Pascal J. Bourguignon |
Subject: |
Re: Purpose of dash # in elisp |
Date: |
Sun, 08 Nov 2009 22:29:12 +0100 |
User-agent: |
Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (darwin) |
Nordlöw <per.nordlow@gmail.com> writes:
> What purpose does # as a quote suffix?
What's the relationship between this question and the one asked in the
Subject: apart from the # character?
Lisp texts are read from left to right. When a quote appears, it is
read alone. Then another object is read (an object is built depending
on the characters read), and the list (quote <the-object-read>) is
returned.
There's no such notion of quote suffix.
Then, when you read # character other characters are read to determine
what must be read. First, if digits appears they are interpreted as
an integer in base ten, and are used as an argument to the "reader
macro" (there's no "reader macro" per se in emacs lisp, although its
reader implements most of the standard reader macros of Common Lisp).
The first non digit character following the # determines what must be
read.
Subchar What is read What is returned
= one expression that expression this expression is
remembered
under the numerical index
given.
# nothing the expression that
was remembered under
the given numerical
index.
' one expression the list (function that-expression)
: the name of a new uninterned symbol with that name
a symbol
( a list a string with properties (the characters
come from the first item of the list
which must be a string, the properties
follow).
etc etc etc You should read the emacs lisp manual.
other nothing nothing an invalid syntax error is
signaled.
--
__Pascal Bourguignon__