3 ms·

Arc gets I/O right

31 points by nickb 18y ago

ajross 18y ago
This is mostly just a list of features without context. I'm sure "ellipsize" really helps for ... something. But I don't know what it is, sadly, because I don't know arc. Shouldn't posts like this be useful for people who aren't part of the cult already? :)
jimbokun 18y ago
I think this is one of the failings of Common Lisp. For the example of snarfing a file into a single string, here are some examples of the fun you can have: http://www.emmett.ca/~sabetts/slurp.html http://www.emmett.ca/~sabetts/slurp.html http://www.tfeb.org/lisp/obscurities.html#SNARFING-FILES http://www.tfeb.org/lisp/obscurities.html#SNARFING-FILES http://www.codecodex.com/wiki/index.php?title=Read_a_file_into_a_byte_array#Common_Lisp http://www.codecodex.com/wiki/index.php?title=Read_a_file_in... http://www.cl-user.net/asp/html-docs/process-file-snippset http://www.cl-user.net/asp/html-docs/process-file-snippset According to the first link, this turns out to be the most efficient and most idiomatic way to do it: (defun slurp-stream5 (stream) (let ((seq (make-array (file-length stream) :element-type 'character :fill-pointer t))) (setf (fill-pointer seq) (read-sequence seq stream)) seq)) Makes sense once you know what all the pieces mean, but not the first thing a new Common Lisp programmer will think of. Then, in the SNARFING-FILES link, turns out it's not correct for all files, anyway, and the "correct" version is considerably longer. EDIT: Oops. The code I pasted DID include the proper file length check (at the cost of reading into an array of characters, instead of a string). So ignore the last sentence of my (unedited) post.
- jrockway 18y ago
  This is why there's such a thing as libraries. When I want to read a file, I say (slurp path).
  - jimbokun 18y ago
    Which library is that?
henning 18y ago
"The whole-file I/O routines, starting with readfile, are a great idea - usually what you want in a file is to read the whole thing. There should be one (file?) for reading the whole file as a string too." This is easy in blub, too: http://commons.apache.org/io/api-release/org/apache/commons/io/FileUtils.html#readFileToString http://commons.apache.org/io/api-release/org/apache/commons/...(java.io.File) , although that URL gets incorrectly parsed by PG's buggy Arc code. :)

31 points by nickb 18y ago

This is mostly just a list of features without context. I'm sure "ellipsize" really helps for ... something. But I don't know what it is, sadly, because I don't know arc. Shouldn't posts like this be useful for people who aren't part of the cult already? :)

jimbokun 18y ago

I think this is one of the failings of Common Lisp. For the example of snarfing a file into a single string, here are some examples of the fun you can have: http://www.emmett.ca/~sabetts/slurp.html http://www.emmett.ca/~sabetts/slurp.html http://www.tfeb.org/lisp/obscurities.html#SNARFING-FILES http://www.tfeb.org/lisp/obscurities.html#SNARFING-FILES http://www.codecodex.com/wiki/index.php?title=Read_a_file_into_a_byte_array#Common_Lisp http://www.codecodex.com/wiki/index.php?title=Read_a_file_in... http://www.cl-user.net/asp/html-docs/process-file-snippset http://www.cl-user.net/asp/html-docs/process-file-snippset According to the first link, this turns out to be the most efficient and most idiomatic way to do it: (defun slurp-stream5 (stream) (let ((seq (make-array (file-length stream) :element-type 'character :fill-pointer t))) (setf (fill-pointer seq) (read-sequence seq stream)) seq)) Makes sense once you know what all the pieces mean, but not the first thing a new Common Lisp programmer will think of. Then, in the SNARFING-FILES link, turns out it's not correct for all files, anyway, and the "correct" version is considerably longer. EDIT: Oops. The code I pasted DID include the proper file length check (at the cost of reading into an array of characters, instead of a string). So ignore the last sentence of my (unedited) post.

jrockway 18y ago
This is why there's such a thing as libraries. When I want to read a file, I say (slurp path).
- jimbokun 18y ago
  Which library is that?

henning 18y ago

"The whole-file I/O routines, starting with readfile, are a great idea - usually what you want in a file is to read the whole thing. There should be one (file?) for reading the whole file as a string too." This is easy in blub, too: http://commons.apache.org/io/api-release/org/apache/commons/io/FileUtils.html#readFileToString http://commons.apache.org/io/api-release/org/apache/commons/...(java.io.File) , although that URL gets incorrectly parsed by PG's buggy Arc code. :)