[PATCH 1/2] rdelim: Add new procedure `for-rdelim-in-port`.

[PATCH 1/2] rdelim: Add new procedure `for-rdelim-in-port`.

[Adam Faiz]

From 302159fe61d9df526911ead8ea6ad823ad8b0443 Mon Sep 17 00:00:00 2001
From: AwesomeAdam54321 <adam.faiz@disroot.org>
Date: Sun, 15 Dec 2024 23:48:30 +0800
Subject: [PATCH 1/2] rdelim: Add new procedure `for-rdelim-in-port`.

* module/ice-9/rdelim.scm (for-rdelim-in-port): Add it.
(for-delimited-in-port): Define as a specialised `for-rdelim-in-port`.
(for-line-in-file): Define as a specialised `for-delimited-in-port`.

These procedures provide a backbone for parsing, with domain-specific
logic implemented as a separate procedure to be passed as an argument.
---
 module/ice-9/rdelim.scm | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/module/ice-9/rdelim.scm b/module/ice-9/rdelim.scm
index d2cd081d7..0bbaaf904 100644
--- a/module/ice-9/rdelim.scm
+++ b/module/ice-9/rdelim.scm
@@ -23,7 +23,10 @@
 ;;; similar to (scsh rdelim) but somewhat incompatible.
 
 (define-module (ice-9 rdelim)
-  #:export (read-line
+  #:export (for-delimited-in-port
+            for-line-in-file
+            for-rdelim-in-port
+            read-line
             read-line!
             read-delimited
             read-delimited!
@@ -206,3 +209,33 @@ characters to read.  By default, there is no limit."
 	      line)
       (else
        (error "unexpected handle-delim value: " handle-delim)))))
+
+(define* (for-rdelim-in-port port proc rdelim-proc
+                             #:key (stop-pred eof-object?))
+  "Call PROC for every (RDELIM-PROC PORT) in PORT until STOP-PRED returns #t.
+RDELIM-PROC has to advance through PORT with every call."
+  (let loop ((rdelim (rdelim-proc port)))
+    (cond ((stop-pred rdelim)
+           (close-port port))
+          (else
+           (proc rdelim)
+           (loop (rdelim-proc port))))))
+
+(define* (for-delimited-in-port port proc
+			        #:key (delims "\n") (handle-delim 'trim))
+  "Call PROC for every delimited line in PORT until the eof-object is reached."
+  (for-rdelim-in-port port proc
+		      (lambda (port)
+			(read-delimited delims port handle-delim))))
+
+(define* (for-line-in-file file proc
+                           #:key (encoding #f) (guess-encoding #f))
+  "Call PROC for every line in FILE until the eof-object is reached.
+FILE must be a filename string.
+
+The line provided to PROC is guaranteed to be a string."
+  (call-with-input-file
+      file
+    (lambda (port)
+      (for-delimited-in-port port proc))
+    #:encoding encoding #:guess-encoding guess-encoding))
-- 
2.41.0

[PATCH 2/2] doc: Add documentation for `for-rdelim-in-port` and, related procedures.

[Adam Faiz]

From b271d059615571d0d50027758494b8dbb5e8625e Mon Sep 17 00:00:00 2001
From: AwesomeAdam54321 <adam.faiz@disroot.org>
Date: Mon, 16 Dec 2024 22:55:41 +0800
Subject: [PATCH 2/2] doc: Add documentation for `for-rdelim-in-port` and
 related procedures.

* doc/ref/api-io.texi (for-rdelim-in-port): Document API.
(for-delimited-in-port): Likewise.
(for-line-in-file): Likewise.
---
 doc/ref/api-io.texi | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/doc/ref/api-io.texi b/doc/ref/api-io.texi
index 79bc9e9d6..23e316c27 100644
--- a/doc/ref/api-io.texi
+++ b/doc/ref/api-io.texi
@@ -984,6 +984,28 @@ used.  This procedure is equivalent to:
 @end lisp
 @end deffn
 
+@deffn {Scheme Procedure} for-rdelim-in-port port proc rdelim-proc @
+        [#:stop-pred=eof-object?]
+For every unit provided by @code{(rdelim-proc port)}, provide
+this unit(rdelim) to @var{proc} to be processed. This will continue throughout
+@var{port} until @var{stop-pred} returns @code{#t}.
+@var{stop-pred} is @code{eof-object?} by default.
+@var{rdelim-proc} has to advance through @var{port} with every call made to it.
+@end deffn
+
+@deffn {Scheme Procedure} for-delimited-in-port port proc @
+        [#:delims=''\n''] [#:handle-delim='trim]
+Call @var{proc} for every line delimited by @var{delims} in @var{port}.
+@end deffn
+
+@deffn {Scheme Procedure} for-line-in-file file proc @
+        [#:encoding=#f] [#:guess-encoding=#f]
+Call @var{proc} for every line in @var{file}.
+@var{file} must be a filename string.
+
+The line provided to @var{proc} is guaranteed to be a string.
+@end deffn
+
 @node Default Ports
 @subsection Default Ports for Input, Output and Errors
 @cindex Default ports
-- 
2.41.0

[PATCH] test-suite: Add tests for `for-rdelim-in-port`-related functions.

[Adam Faiz]

From 258d20a9665e6f845a167258c33374a00e734885 Mon Sep 17 00:00:00 2001
From: AwesomeAdam54321 <adam.faiz@disroot.org>
Date: Tue, 17 Dec 2024 12:20:52 +0800
Subject: [PATCH] test-suite: Add tests for `for-rdelim-in-port`-related
 functions.

* test-suite/tests/ports.test: Add test cases for
`for-delimited-in-port` and `for-line-in-file`.
---
 test-suite/tests/ports.test | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/test-suite/tests/ports.test b/test-suite/tests/ports.test
index bec5e356c..15d515f1f 100644
--- a/test-suite/tests/ports.test
+++ b/test-suite/tests/ports.test
@@ -2089,6 +2089,28 @@
           (not (string-index (%search-load-path (basename (test-file)))
                              #\\))))))
 
+(let ((lst '())
+      (lines '())
+      (string "line1\nline2\nline3")
+      (filename (test-file)))
+  (call-with-input-string
+      "A\0B\0C"
+    (lambda (port)
+      (pass-if "for-delimited-in-port returns true upon completion"
+        (for-delimited-in-port port
+                               (lambda (entry)
+                                 (set! lst (cons entry lst)))
+                               #:delims "\0")
+        (equal? lst '("C" "B" "A")))))
+  (let ((port (open-output-file filename)))
+    (display string port)
+    (close-port port))
+  (pass-if "for-line-in-file returns true upon completion"
+    (for-line-in-file filename
+                      (lambda (line)
+                        (set! lines (cons line lines))))
+    (equal? lines '("line3" "line2" "line1"))))
+
 (delete-file (test-file))
 
 ;;; Local Variables:
-- 
2.46.0

Re: [PATCH] test-suite: Add tests for `for-rdelim-in-port`-related functions.

[Nala Ginrut]

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The preferred activity in your design is more like for-each family, say,
handle the result inside the proc without return result. So maybe it should
be named as for-each-*-in-file, which is more understandable in the first
glance.
Best regards.

On Tue, Dec 17, 2024, 13:31 Adam Faiz <adam.faiz@disroot.org> wrote:

> From 258d20a9665e6f845a167258c33374a00e734885 Mon Sep 17 00:00:00 2001
> From: AwesomeAdam54321 <adam.faiz@disroot.org>
> Date: Tue, 17 Dec 2024 12:20:52 +0800
> Subject: [PATCH] test-suite: Add tests for `for-rdelim-in-port`-related
>  functions.
>
> * test-suite/tests/ports.test: Add test cases for
> `for-delimited-in-port` and `for-line-in-file`.
> ---
>  test-suite/tests/ports.test | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/test-suite/tests/ports.test b/test-suite/tests/ports.test
> index bec5e356c..15d515f1f 100644
> --- a/test-suite/tests/ports.test
> +++ b/test-suite/tests/ports.test
> @@ -2089,6 +2089,28 @@
>            (not (string-index (%search-load-path (basename (test-file)))
>                               #\\))))))
>
> +(let ((lst '())
> +      (lines '())
> +      (string "line1\nline2\nline3")
> +      (filename (test-file)))
> +  (call-with-input-string
> +      "A\0B\0C"
> +    (lambda (port)
> +      (pass-if "for-delimited-in-port returns true upon completion"
> +        (for-delimited-in-port port
> +                               (lambda (entry)
> +                                 (set! lst (cons entry lst)))
> +                               #:delims "\0")
> +        (equal? lst '("C" "B" "A")))))
> +  (let ((port (open-output-file filename)))
> +    (display string port)
> +    (close-port port))
> +  (pass-if "for-line-in-file returns true upon completion"
> +    (for-line-in-file filename
> +                      (lambda (line)
> +                        (set! lines (cons line lines))))
> +    (equal? lines '("line3" "line2" "line1"))))
> +
>  (delete-file (test-file))
>
>  ;;; Local Variables:
> --
> 2.46.0
>

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Re: [PATCH] test-suite: Add tests for `for-rdelim-in-port`-related functions.

[Mikael Djurfeldt]

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Do others think this as well? To me, the shorter names which Adam selected
seem more palatable. Otherwise they get a bit long.

Den tis 17 dec. 2024 06:11Nala Ginrut <nalaginrut@gmail.com> skrev:

> The preferred activity in your design is more like for-each family, say,
> handle the result inside the proc without return result. So maybe it should
> be named as for-each-*-in-file, which is more understandable in the first
> glance.
> Best regards.
>
> On Tue, Dec 17, 2024, 13:31 Adam Faiz <adam.faiz@disroot.org> wrote:
>
>> From 258d20a9665e6f845a167258c33374a00e734885 Mon Sep 17 00:00:00 2001
>> From: AwesomeAdam54321 <adam.faiz@disroot.org>
>> Date: Tue, 17 Dec 2024 12:20:52 +0800
>> Subject: [PATCH] test-suite: Add tests for `for-rdelim-in-port`-related
>>  functions.
>>
>> * test-suite/tests/ports.test: Add test cases for
>> `for-delimited-in-port` and `for-line-in-file`.
>> ---
>>  test-suite/tests/ports.test | 22 ++++++++++++++++++++++
>>  1 file changed, 22 insertions(+)
>>
>> diff --git a/test-suite/tests/ports.test b/test-suite/tests/ports.test
>> index bec5e356c..15d515f1f 100644
>> --- a/test-suite/tests/ports.test
>> +++ b/test-suite/tests/ports.test
>> @@ -2089,6 +2089,28 @@
>>            (not (string-index (%search-load-path (basename (test-file)))
>>                               #\\))))))
>>
>> +(let ((lst '())
>> +      (lines '())
>> +      (string "line1\nline2\nline3")
>> +      (filename (test-file)))
>> +  (call-with-input-string
>> +      "A\0B\0C"
>> +    (lambda (port)
>> +      (pass-if "for-delimited-in-port returns true upon completion"
>> +        (for-delimited-in-port port
>> +                               (lambda (entry)
>> +                                 (set! lst (cons entry lst)))
>> +                               #:delims "\0")
>> +        (equal? lst '("C" "B" "A")))))
>> +  (let ((port (open-output-file filename)))
>> +    (display string port)
>> +    (close-port port))
>> +  (pass-if "for-line-in-file returns true upon completion"
>> +    (for-line-in-file filename
>> +                      (lambda (line)
>> +                        (set! lines (cons line lines))))
>> +    (equal? lines '("line3" "line2" "line1"))))
>> +
>>  (delete-file (test-file))
>>
>>  ;;; Local Variables:
>> --
>> 2.46.0
>>
>

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Re: [PATCH] test-suite: Add tests for `for-rdelim-in-port`-related functions.

[Mikael Djurfeldt]

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I think these procedures are handy in common situations. There has been a
discussion about generalization. I have the feeling that such
generalization either already exists in some SRFI or that one should put
some deep thinking into how to represent flexible iteration in Scheme.

I don't think it would be bad to apply Adam's patch, though, or that
placing it in (ice-9 rdelim) is unnatural.

If no one objects, I will apply the patch in a couple of days with the
current naming scheme but modified by the following:

I think "in-port" is redundant and slightly confusing and ambiguous (c.f.
"input") and would replace it with "from-port" to conform with other
procedure names (such as with-input-from-port). On the other hand,
"line-in-file" feels natural despite the existence of with-input-from-file.

On Tue, Dec 17, 2024 at 8:21 AM Mikael Djurfeldt <mikael@djurfeldt.com>
wrote:

> Do others think this as well? To me, the shorter names which Adam selected
> seem more palatable. Otherwise they get a bit long.
>
> Den tis 17 dec. 2024 06:11Nala Ginrut <nalaginrut@gmail.com> skrev:
>
>> The preferred activity in your design is more like for-each family, say,
>> handle the result inside the proc without return result. So maybe it should
>> be named as for-each-*-in-file, which is more understandable in the first
>> glance.
>> Best regards.
>>
>> On Tue, Dec 17, 2024, 13:31 Adam Faiz <adam.faiz@disroot.org> wrote:
>>
>>> From 258d20a9665e6f845a167258c33374a00e734885 Mon Sep 17 00:00:00 2001
>>> From: AwesomeAdam54321 <adam.faiz@disroot.org>
>>> Date: Tue, 17 Dec 2024 12:20:52 +0800
>>> Subject: [PATCH] test-suite: Add tests for `for-rdelim-in-port`-related
>>>  functions.
>>>
>>> * test-suite/tests/ports.test: Add test cases for
>>> `for-delimited-in-port` and `for-line-in-file`.
>>> ---
>>>  test-suite/tests/ports.test | 22 ++++++++++++++++++++++
>>>  1 file changed, 22 insertions(+)
>>>
>>> diff --git a/test-suite/tests/ports.test b/test-suite/tests/ports.test
>>> index bec5e356c..15d515f1f 100644
>>> --- a/test-suite/tests/ports.test
>>> +++ b/test-suite/tests/ports.test
>>> @@ -2089,6 +2089,28 @@
>>>            (not (string-index (%search-load-path (basename (test-file)))
>>>                               #\\))))))
>>>
>>> +(let ((lst '())
>>> +      (lines '())
>>> +      (string "line1\nline2\nline3")
>>> +      (filename (test-file)))
>>> +  (call-with-input-string
>>> +      "A\0B\0C"
>>> +    (lambda (port)
>>> +      (pass-if "for-delimited-in-port returns true upon completion"
>>> +        (for-delimited-in-port port
>>> +                               (lambda (entry)
>>> +                                 (set! lst (cons entry lst)))
>>> +                               #:delims "\0")
>>> +        (equal? lst '("C" "B" "A")))))
>>> +  (let ((port (open-output-file filename)))
>>> +    (display string port)
>>> +    (close-port port))
>>> +  (pass-if "for-line-in-file returns true upon completion"
>>> +    (for-line-in-file filename
>>> +                      (lambda (line)
>>> +                        (set! lines (cons line lines))))
>>> +    (equal? lines '("line3" "line2" "line1"))))
>>> +
>>>  (delete-file (test-file))
>>>
>>>  ;;; Local Variables:
>>> --
>>> 2.46.0
>>>
>>

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Re: [PATCH 1/2] rdelim: Add new procedure `for-rdelim-in-port`.

[Nala Ginrut]

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Thanks for the work!
I didn’t find anything to be picky about yet in the implementation.

Now there are two things could go further.
1. About the port closing, I don’t insist on my previous suggestion right
now. There may be arguments against it by folks. I’m fine with any.

2. To complete a promising patch, it’s better to have test cases. You may
take a look at the existing tests to learn how.

Best regards.

On Reiwa 6 Dec 17, Tue at 0:22 Adam Faiz <adam.faiz@disroot.org> wrote:

> From 302159fe61d9df526911ead8ea6ad823ad8b0443 Mon Sep 17 00:00:00 2001
> From: AwesomeAdam54321 <adam.faiz@disroot.org>
> Date: Sun, 15 Dec 2024 23:48:30 +0800
> Subject: [PATCH 1/2] rdelim: Add new procedure `for-rdelim-in-port`.
>
> * module/ice-9/rdelim.scm (for-rdelim-in-port): Add it.
> (for-delimited-in-port): Define as a specialised `for-rdelim-in-port`.
> (for-line-in-file): Define as a specialised `for-delimited-in-port`.
>
> These procedures provide a backbone for parsing, with domain-specific
> logic implemented as a separate procedure to be passed as an argument.
> ---
>  module/ice-9/rdelim.scm | 35 ++++++++++++++++++++++++++++++++++-
>  1 file changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/module/ice-9/rdelim.scm b/module/ice-9/rdelim.scm
> index d2cd081d7..0bbaaf904 100644
> --- a/module/ice-9/rdelim.scm
> +++ b/module/ice-9/rdelim.scm
> @@ -23,7 +23,10 @@
>  ;;; similar to (scsh rdelim) but somewhat incompatible.
>
>  (define-module (ice-9 rdelim)
> -  #:export (read-line
> +  #:export (for-delimited-in-port
> +            for-line-in-file
> +            for-rdelim-in-port
> +            read-line
>              read-line!
>              read-delimited
>              read-delimited!
> @@ -206,3 +209,33 @@ characters to read.  By default, there is no limit."
>               line)
>        (else
>         (error "unexpected handle-delim value: " handle-delim)))))
> +
> +(define* (for-rdelim-in-port port proc rdelim-proc
> +                             #:key (stop-pred eof-object?))
> +  "Call PROC for every (RDELIM-PROC PORT) in PORT until STOP-PRED returns
> #t.
> +RDELIM-PROC has to advance through PORT with every call."
> +  (let loop ((rdelim (rdelim-proc port)))
> +    (cond ((stop-pred rdelim)
> +           (close-port port))
> +          (else
> +           (proc rdelim)
> +           (loop (rdelim-proc port))))))
> +
> +(define* (for-delimited-in-port port proc
> +                               #:key (delims "\n") (handle-delim 'trim))
> +  "Call PROC for every delimited line in PORT until the eof-object is
> reached."
> +  (for-rdelim-in-port port proc
> +                     (lambda (port)
> +                       (read-delimited delims port handle-delim))))
> +
> +(define* (for-line-in-file file proc
> +                           #:key (encoding #f) (guess-encoding #f))
> +  "Call PROC for every line in FILE until the eof-object is reached.
> +FILE must be a filename string.
> +
> +The line provided to PROC is guaranteed to be a string."
> +  (call-with-input-file
> +      file
> +    (lambda (port)
> +      (for-delimited-in-port port proc))
> +    #:encoding encoding #:guess-encoding guess-encoding))
> --
> 2.41.0
>

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