From: Mark Walters <markwalters1009@gmail.com>
To: Austin Clements <amdragon@MIT.EDU>, notmuch@notmuchmail.org
Subject: Re: [PATCH v2 0/5] Make Emacs search use sexp format
In-Reply-To: <1369934016-22308-1-git-send-email-amdragon@mit.edu>
References: <1369934016-22308-1-git-send-email-amdragon@mit.edu>
User-Agent: Notmuch/0.14+255~gff3cc55 (http://notmuchmail.org) Emacs/23.4.1
	(i486-pc-linux-gnu)
Date: Fri, 31 May 2013 23:38:37 +0100
Message-ID: <87y5aug4gi.fsf@qmul.ac.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: tomi.ollila@iki.fi
Precedence: list


This version LGTM +1. I will let you and Tomi decide which shell magic
to go with.

One very trivial comment on a comment below

Best wishes

Mark

Austin Clements <amdragon@MIT.EDU> writes:

> This is v2 of id:1368851472-5382-1-git-send-email-amdragon@mit.edu.
> The most substantial change from v1 is that the streaming S-expression
> parser now requires the caller to invoke it from the appropriate
> buffer and no longer attempts to track the buffer itself.  For subtle
> reasons arising from per-window points, the only *correct* way to use
> the interface before required the caller to invoke it from the
> appropriate buffer anyway (or risk losing track of what had been
> parsed).  The only place that currently invokes the streaming
> S-expression parser already satisfied this requirement.
>
> I decided *not* to use --stderr to redirect stderr.  As discussed on
> IRC, --stderr causes serious problems for wrapper scripts, which
> either have to handle --stderr themselves or risk mixing their own
> stderr with stdout (e.g., errors from ssh) or, worse, redirecting
> notmuch's stderr to a (world-readable) file on a *remote* machine.  I
> did fix the exec-path problem that Tomi pointed out, so
> notmuch-command will continue to be searched for in exec-path, like it
> currently is.
>
> The diff from v1 is below, with whitespace changes because of
> re-indentation in the S-expression parser.
>
> diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
> index a543471..180f63d 100644
> --- a/emacs/notmuch-lib.el
> +++ b/emacs/notmuch-lib.el
> @@ -493,10 +493,13 @@ status."
>    (let* ((err-file (make-temp-file "nmerr"))
>  	 ;; Use a pipe
>  	 (process-connection-type nil)
> +	 ;; Find notmuch using Emacs' `exec-path'
> +	 (command (or (executable-find notmuch-command)
> +		      (error "command not found: %s" notmuch-command)))
>  	 (proc (apply #'start-process name buffer
>  		      "sh" "-c"
>  		      "ERR=\"$1\"; shift; exec \"$0\" \"$@\" 2>\"$ERR\""
> -		      notmuch-command err-file args)))
> +		      command err-file args)))
>      (process-put proc 'err-file err-file)
>      (process-put proc 'sub-sentinel sentinel)
>      (process-put proc 'real-command (cons notmuch-command args))
> @@ -507,7 +510,7 @@ status."
>    (let ((err-file (process-get proc 'err-file))
>  	(sub-sentinel (process-get proc 'sub-sentinel))
>  	(real-command (process-get proc 'real-command)))
> -    (condition-case-unless-debug err
> +    (condition-case err
>  	(progn
>  	  ;; Invoke the sub-sentinel, if any
>  	  (when sub-sentinel
> @@ -530,7 +533,8 @@ status."
>  	    (when warnings
>  	      (notmuch-logged-error (car warnings) (cdr warnings)))))
>        (error
> -       ;; Don't signal an error from a sentinel
> +       ;; Emacs behaves strangely if error an error escapes from a
> +       ;; sentinel, so turns errors into messages.

2 typos: "error an error" and turns should be turn.

>         (message "%s" (error-message-string err))))
>      (ignore-errors (delete-file err-file))))
>  
> diff --git a/emacs/notmuch-parser.el b/emacs/notmuch-parser.el
> index 1b7cf64..d59c0e1 100644
> --- a/emacs/notmuch-parser.el
> +++ b/emacs/notmuch-parser.el
> @@ -21,8 +21,8 @@
>  
>  (require 'cl)
>  
> -(defun notmuch-sexp-create-parser (buffer)
> -  "Return a streaming S-expression parser that reads from BUFFER.
> +(defun notmuch-sexp-create-parser ()
> +  "Return a new streaming S-expression parser.
>  
>  This parser is designed to incrementally read an S-expression
>  whose structure is known to the caller.  Like a typical
> @@ -33,12 +33,11 @@ input to be a list and descends into it, allowing its elements to
>  be read one at a time or further descended into.  Both functions
>  can return 'retry to indicate that not enough input is available.
>  
> -The parser always consumes input from BUFFER's point.  Hence, the
> -caller is allowed to delete any data before point and may
> -resynchronize after an error by moving point."
> +The parser always consumes input from point in the current
> +buffer.  Hence, the caller is allowed to delete any data before
> +point and may resynchronize after an error by moving point."
>  
>    (vector 'notmuch-sexp-parser
> -	  buffer
>  	  ;; List depth
>  	  0
>  	  ;; Partial parse position marker
> @@ -46,13 +45,12 @@ resynchronize after an error by moving point."
>  	  ;; Partial parse state
>  	  nil))
>  
> -(defmacro notmuch-sexp--buffer (sp)        `(aref ,sp 1))
> -(defmacro notmuch-sexp--depth (sp)         `(aref ,sp 2))
> -(defmacro notmuch-sexp--partial-pos (sp)   `(aref ,sp 3))
> -(defmacro notmuch-sexp--partial-state (sp) `(aref ,sp 4))
> +(defmacro notmuch-sexp--depth (sp)         `(aref ,sp 1))
> +(defmacro notmuch-sexp--partial-pos (sp)   `(aref ,sp 2))
> +(defmacro notmuch-sexp--partial-state (sp) `(aref ,sp 3))
>  
>  (defun notmuch-sexp-read (sp)
> -  "Consume and return the value at point in SP's buffer.
> +  "Consume and return the value at point in the current buffer.
>  
>  Returns 'retry if there is insufficient input to parse a complete
>  value (though it may still move point over whitespace).  If the
> @@ -61,14 +59,13 @@ list, this moves point just past the terminator and returns 'end.
>  Otherwise, this moves point to just past the end of the value and
>  returns the value."
>  
> -  (with-current-buffer (notmuch-sexp--buffer sp)
>    (skip-chars-forward " \n\r\t")
>    (cond ((eobp) 'retry)
>  	((= (char-after) ?\))
>  	 ;; We've reached the end of a list
>  	 (if (= (notmuch-sexp--depth sp) 0)
>  	     ;; .. but we weren't in a list.  Let read signal the
> -	       ;; error.
> +	     ;; error to be consistent with all other code paths.
>  	     (read (current-buffer))
>  	   ;; Go up a level and return an end token
>  	   (decf (notmuch-sexp--depth sp))
> @@ -124,7 +121,7 @@ returns the value."
>  		   'retry))
>  	     (end-of-file
>  	      (goto-char start)
> -		'retry)))))))
> +	      'retry))))))
>  
>  (defun notmuch-sexp-begin-list (sp)
>    "Parse the beginning of a list value and enter the list.
> @@ -136,7 +133,6 @@ returns t.  Later calls to `notmuch-sexp-read' will return the
>  elements inside the list.  If the input in buffer is not the
>  beginning of a list, throw invalid-read-syntax."
>  
> -  (with-current-buffer (notmuch-sexp--buffer sp)
>    (skip-chars-forward " \n\r\t")
>    (cond ((eobp) 'retry)
>  	((= (char-after) ?\()
> @@ -146,7 +142,7 @@ beginning of a list, throw invalid-read-syntax."
>  	(t
>  	 ;; Skip over the bad character like `read' does
>  	 (forward-char)
> -	   (signal 'invalid-read-syntax (list (string (char-before))))))))
> +	 (signal 'invalid-read-syntax (list (string (char-before)))))))
>  
>  (defun notmuch-sexp-eof (sp)
>    "Signal an error if there is more data in SP's buffer.
> @@ -154,10 +150,9 @@ beginning of a list, throw invalid-read-syntax."
>  Moves point to the beginning of any trailing data or to the end
>  of the buffer if there is only trailing whitespace."
>  
> -  (with-current-buffer (notmuch-sexp--buffer sp)
>    (skip-chars-forward " \n\r\t")
>    (unless (eobp)
> -      (error "Trailing garbage following expression"))))
> +    (error "Trailing garbage following expression")))
>  
>  (defvar notmuch-sexp--parser nil
>    "The buffer-local notmuch-sexp-parser instance.
> @@ -170,7 +165,7 @@ Used by `notmuch-sexp-parse-partial-list'.")
>  (defun notmuch-sexp-parse-partial-list (result-function result-buffer)
>    "Incrementally parse an S-expression list from the current buffer.
>  
> -This function consume an S-expression list from the current
> +This function consumes an S-expression list from the current
>  buffer, applying RESULT-FUNCTION in RESULT-BUFFER to each
>  complete value in the list.  It operates incrementally and should
>  be called whenever the input buffer has been extended with
> @@ -180,7 +175,7 @@ move point in the input buffer."
>    ;; Set up the initial state
>    (unless (local-variable-p 'notmuch-sexp--parser)
>      (set (make-local-variable 'notmuch-sexp--parser)
> -	 (notmuch-sexp-create-parser (current-buffer)))
> +	 (notmuch-sexp-create-parser))
>      (set (make-local-variable 'notmuch-sexp--state) 'begin))
>    (let (done)
>      (while (not done)