diff mbox

Adding wc to Bournish

Message ID 20160526192755.GB28047@debian-netbook
State New
Headers show

Commit Message

Efraim Flashner May 26, 2016, 7:27 p.m. UTC
Here's where I'm currently at with 'wc'. Currently I'm getting an error
about having the wrong number of arguments for lambda (I assume)

;;; /home/efraim/workspace/guix/guix/build/bournish.scm:143:2: warning:
wrong number of arguments to `#<tree-il (lambda () (lambda-case (((lines
words chars) #f #f #f () (lines-24244 words-24245 chars-24246)) (apply
(toplevel format) (const #t) (const "~a ~a ~a ~a~%") (lexical lines
lines-24244) (lexical words words-24245) (lexical chars chars-24246)
(lexical file file-24242)))))>'

It's not ready as-is, but I wanted to show what I had so far :)

Comments

Eric Bavier May 27, 2016, 1:37 p.m. UTC | #1
On 2016-05-26 14:27, Efraim Flashner wrote:
> Here's where I'm currently at with 'wc'. Currently I'm getting an error
> about having the wrong number of arguments for lambda (I assume)
[...]
> +(define (wc-command file)
> +  ((lambda (lines words chars) ; lambda doesn't like 3 variables
> +     (format #t "~a ~a ~a ~a~%" lines words chars file))
> +   (call-with-input-file file lines+chars)))
[...]
> 
> ;;; /home/efraim/workspace/guix/guix/build/bournish.scm:143:2: warning:
> wrong number of arguments to `#<tree-il (lambda () (lambda-case 
> (((lines
> words chars) #f #f #f () (lines-24244 words-24245 chars-24246)) (apply
> (toplevel format) (const #t) (const "~a ~a ~a ~a~%") (lexical lines
> lines-24244) (lexical words words-24245) (lexical chars chars-24246)
> (lexical file file-24242)))))>'

I think you might just be missing a 'call-with-values':

(define (wc-command file)
   (call-with-values
     (call-with-input-file file lines+chars)
     (lambda (lines words chars) ...)))
Taylan Ulrich Bayırlı =?utf-8?Q?=2FKammer?= May 27, 2016, 3:28 p.m. UTC | #2
Eric Bavier <ericbavier@openmailbox.org> writes:

> On 2016-05-26 14:27, Efraim Flashner wrote:
>> Here's where I'm currently at with 'wc'. Currently I'm getting an error
>> about having the wrong number of arguments for lambda (I assume)
> [...]
>> +(define (wc-command file)
>> +  ((lambda (lines words chars) ; lambda doesn't like 3 variables
>> +     (format #t "~a ~a ~a ~a~%" lines words chars file))
>> +   (call-with-input-file file lines+chars)))
> [...]
>>
>> ;;; /home/efraim/workspace/guix/guix/build/bournish.scm:143:2: warning:
>> wrong number of arguments to `#<tree-il (lambda () (lambda-case
>> (((lines
>> words chars) #f #f #f () (lines-24244 words-24245 chars-24246)) (apply
>> (toplevel format) (const #t) (const "~a ~a ~a ~a~%") (lexical lines
>> lines-24244) (lexical words words-24245) (lexical chars chars-24246)
>> (lexical file file-24242)))))>'
>
> I think you might just be missing a 'call-with-values':
>
> (define (wc-command file)
>   (call-with-values
>     (call-with-input-file file lines+chars)
>     (lambda (lines words chars) ...)))

I believe this should be

    (define (wc-command file)
      (call-with-values
        (lambda ()
          (call-with-input-file file lines+chars))
        (lambda (lines words chars)
          ...)))

since both arguments to call-with-values must be procedures.


By the way, I prefer SRFI-11 let-values (standardized in R7RS):

    (define (wc-command file)
      (let-values (((lines words chars)
                    (call-with-input-file file lines+chars)))
        ...))

The large number of parentheses involved are annoying at first, but as I
used it more often I grew accustomed to it and aren't bothered at all
anymore, neither in writing nor reading the code.  I also had some valid
uses of let*-values occasionally; I find it neat how it allows "piping"
a number of different values through a sequence of procedures, without
having to allocate any intermediate data structures.

Taylan
David Thompson May 27, 2016, 3:32 p.m. UTC | #3
On Fri, May 27, 2016 at 11:28 AM, Taylan Ulrich Bayırlı/Kammer
<taylanbayirli@gmail.com> wrote:

> By the way, I prefer SRFI-11 let-values (standardized in R7RS):
>
>     (define (wc-command file)
>       (let-values (((lines words chars)
>                     (call-with-input-file file lines+chars)))
>         ...))
>
> The large number of parentheses involved are annoying at first, but as I
> used it more often I grew accustomed to it and aren't bothered at all
> anymore, neither in writing nor reading the code.  I also had some valid
> uses of let*-values occasionally; I find it neat how it allows "piping"
> a number of different values through a sequence of procedures, without
> having to allocate any intermediate data structures.

I second this.  I got very good mileage out of let*-values while
making my game for the last Lisp Game Jam.

https://git.dthompson.us/lisp-game-jam-2016-spring.git/blob/HEAD:/lisparuga/world.scm#l273

- Dave
diff mbox

Patch

diff --git a/guix/build/bournish.scm b/guix/build/bournish.scm
index 4022796..d133796 100644
--- a/guix/build/bournish.scm
+++ b/guix/build/bournish.scm
@@ -1,5 +1,6 @@ 
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016 Efraim Flashner <efraim@flashner.co.il>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -21,11 +22,13 @@ 
   #:use-module (system base compile)
   #:use-module (system repl command)
   #:use-module (system repl common)
+  ;#:use-module (ice-9 streams)
   #:use-module (ice-9 rdelim)
   #:use-module (ice-9 match)
   #:use-module (ice-9 ftw)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-41)
   #:export (%bournish-language))
 
 ;;; Commentary:
@@ -103,6 +106,56 @@  characters."
        ((@ (guix build utils) dump-port) port (current-output-port))
        *unspecified*)))
 
+(define (file-size file)
+    (stat:size (stat file)))
+
+(define (wc-c-command file)
+  ;; Faster when only `wc -c' is called
+  (file-size file))
+
+(define (wc-l-command file)
+  ;; Faster when only `wc -l' is called
+  (stream-length
+    (stream-filter
+      (lambda (chr)
+        (char=? chr #\newline))
+      (port->stream (open-file file "r")))))
+
+;(define (wc-l-command file)
+;  (call-with-input-file file
+;    (lambda (port)
+
+(define (lines+chars port)
+  ;; Return the number of lines and number of chars read from PORT.
+  (let loop ((lines 0) (words 0) (chars 0))
+    (match (read-char port)
+      ((? eof-object?)              ;done!
+       (values lines words chars))
+      (#\newline                    ;recurse
+       (loop (1+ lines) (1+ words) (1+ chars)))
+      ((and (char-set<= ? char-set:blank) ; need to fix/replace the '?'
+            (char-set<= (peek-char port) char-set:graphic))
+       (loop lines (1+ words) (1+ chars)))
+      (_                            ;recurse
+       (loop lines words (1+ chars))))))
+
+(define (wc-command file)
+  ((lambda (lines words chars) ; lambda doesn't like 3 variables
+     (format #t "~a ~a ~a ~a~%" lines words chars file))
+   (call-with-input-file file lines+chars)))
+
+;  let-values is undefined
+;  (let-values (((lines words chars)
+;    (call-with-input-file file lines+chars)))
+;      (format #t "~a ~a ~a ~a~%" lines chars words file)))
+
+;(define (wc-command file)
+;  (let ((wc-l (wc-l-command file))
+;        (wc-w (wc-w-command file))
+;        (wc-c (wc-c-command file)))
+;    (format #t "~{~a ~}\n"
+;            (list wc-l wc-w wc-c file))))
+
 (define (help-command . _)
   (display "\
 Hello, this is Bournish, a minimal Bourne-like shell in Guile!
@@ -129,7 +182,8 @@  commands such as 'ls' and 'cd'; it lacks globbing, pipes---everything.\n"))
     ("help"   ,help-command)
     ("ls"     ,ls-command)
     ("which"  ,which-command)
-    ("cat"    ,cat-command)))
+    ("cat"    ,cat-command)
+    ("wc"     ,wc-command)))
 
 (define (read-bournish port env)
   "Read a Bournish expression from PORT, and return the corresponding Scheme