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#1
Whither newLISP? / READ ... why is it there?
June 27, 2005, 05:57:46 AM
I give up.



Why do thousands (maybe less?) of programmers use READ in Lisp?



Why did they come up with READ in the first place?



I dunno... I just use it now and then, and it's handy.



Let's close this thread. At least from my side, I don't have that much time to spend on this.



Have fun.

-Leo-
#2
Whither newLISP? /
June 26, 2005, 11:22:16 AM
Looks good. Thanx!

-Leo-
#3
Whither newLISP? /
June 26, 2005, 05:19:25 AM
Maybe this makes it more clear.  Think of a file that I want to read in with the following:



[bof]

some-atom (and then a list with information) (and another list (with yet another list running into a newline) and some more) (this maybe formatted in 80-column text) some-other atom (and again a list with a number 1.85 and a "string") 2.50 "another string"

[eof]



How would you read this file, controlled, without evaluating, one experession after the other? Note: the contents does not have to be Lisp, it could be anything.



READ does this. How is this done in newLisp?



TIA

-Leo-
#4
Whither newLISP? /
June 25, 2005, 02:03:59 PM
Quote from: "newdep"Isnt 'load doing that?


Nope.



Quote from the newLisp manual:
QuoteLoads and translates newLISP from a source file specified in one or more str-file-name and evaluates the expressions contained in the file(s).


It should not evaluate and READ doesn't



Besides: I want a controlled one by one READ of S-expressions, for example to operate on values sequentially.



-Leo-
#5
Whither newLISP? /
June 25, 2005, 02:01:14 PM
BTW



An S-expression in a file may run over a line

read-line only reads until a cr-lf



Do you guys think READ is obsolete?? How do you then perform this type of READing?



-Leo-
#6
Whither newLISP? /
June 25, 2005, 01:56:54 PM
Simple:

(from xLisp)

read an expression

(read [<stream> [<eofp> [<eof> [<rflag>]]]])

<stream>   the input stream (default, or NIL, is *standard-input*, T is *terminal-io*)

<eofp>   When T, signal an error on end of file, when NIL return <eof> (default is T)

<eof>   the value to return on end of file (default is NIL)

<rflag>   recursive read flag. The value is ignored

returns   the expression read



Actually the basic READ doesn't need any parameter, it uses the *standard-input*



READ is for getting a syntactically valid S-expresseion. Only that value is returned. The S-expression is not evaluated.



Its practical for reading in S-expression from a file, without evaluation.



HTH

-Leo-
#7
Whither newLISP? / READ
June 25, 2005, 12:34:47 PM
Hi, here's my version of READ:



It is used to read a text file one atom or list at a time.

I'm out of practise since I haven't programmed in Lisp since 1993, and I'm new to newLisp

If someone likes to make an elegant version, be my guest!


Code Select
(define (read fHandle, i result)
(setq result "")
(do-while (not (= i nil))
 (setq i (read-char fHandle))
 (cond ((= i nil) (setq result "EOF"))
((not (member i '(32 13 10 40))) ;legal character
;; not a list
                     (setq result (append (char i) (read-atom fHandle)))
                     (setq i nil))
                    ((= i 40)
;; opening parethesis - read in the list
                     (setq result (append (char i) (read-list fHandle)))
(setq i nil))
 )
)
   (if (= result "EOF") nil (sym result))
)

(define (read-atom fHandle, x y)
(setq y "")
(do-while (not (= x nil))
 (setq x (read-char fHandle))
     (cond ((not (member x '(32 13 10 40)))
                     (setq y (append y (char x))))
                    ((member x '(32 13 10 40)) (setq x nil))
              )
    )
y)

(define (read-list fHandle, x y flag)
(setq flag 1)
(setq y "")
(do-while (not (= x nil))
 (setq x (read-char fHandle))
 (if (= x 40) (inc 'flag 1))
 (if (= x 41) (dec 'flag 1))
     (cond ((and (= x 41) (= flag 0))
                     (setq y (append y (char x)))
    (setq x nil))
              ((not (member x '(13 10)))
                     (setq y (append y (char x))))
              )
    )
y)
#8
Whither newLISP? /
June 25, 2005, 07:50:46 AM
Quote from: "HPW"Maybe it is not like muLISP-read, but I use it in code ported from autolisp.



So it should be possible to code the wanted behaviour.



You can list all test-cases of input and wanted output and then it should be possible.


Yes, I could. Thanx for helping.

I'm a little suprised that such a basic function is not available. Lisp is a read-eval loop. There's a read-char, read-line,  read-key etc, but not the basic READ.
#9
Whither newLISP? /
June 24, 2005, 08:47:22 AM
Thanx, but this is also not what I'm looking for.

It should not evaluate and read an atom or a list at the time.


Quote from: "HPW"I used this read-emulation:
Code Select

(define (read readstr   readret)
(cond
((float readstr)
(if (find "." readstr)
(setq readret (float readstr))
(setq readret (integer readstr))
)
)
((=(slice readstr 0 1)"(") ;)
(setq readret(eval-string(append "'" readstr)))
)
(true
(setq readret (symbol readstr))
)
)
)
#10
Whither newLISP? / READ
June 24, 2005, 08:43:18 AM
Quote from: "eddier"If you are reading from a file:
Code Select

(eval-string (read-file "filename"))

If you just want to evaluate something from the console
Code Select

(eval-string (read-line))

Hope this helps.



Eddie


No, this is not what READ does. READ reads one atom or a list at a time, but does not evaluate. Quoted text is read in as strings, number as numers etc.

and there is no cr-lf.
#11
Whither newLISP? / READ
June 23, 2005, 12:39:52 PM
Hi, I'm new to newLisp, but not to lisp.

In the lisp I used most often muLISP (a looong time ago) there was a READ function, to read a normal LISP expression.

Why is that not present in newLISP? Does anyone have ready made READ function?



TIA

-Leo-
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