bug#48180: ruby-mode.el: fix font lock for puts and printf

bug#48180: ruby-mode.el: fix font lock for puts and printf

[Steve Purcell]

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Tags: patch

Both these methods can be called without arguments, so the font
locking of "bare" calls to either is incorrect.  The fix is to
font-lock them as for other kernel methods which accepts zero or more
arguments.


In GNU Emacs 28.0.50 (build 1, x86_64-apple-darwin20.4.0, NS appkit-2022.44 Version 10.16 (Build 20E232))
Repository revision: 30d974bf5c02a1367291fbb6fa17a182bb7974b7
Repository branch: master
Windowing system distributor 'Apple', version 10.3.2022
System Description:  macOS 11.3

Configured using:
 'configure
 --prefix=/nix/store/kvhx6vn5wvif4s9aiwp75v8pxplh19i2-emacs-gcc-20210502.0
 --disable-build-details --with-modules --with-ns
 --disable-ns-self-contained --with-native-compilation
 CFLAGS=-DMAC_OS_X_VERSION_MAX_ALLOWED=101200'


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From 6041b603c0a4cadbd1eaa92a2d9c0162bedbd939 Mon Sep 17 00:00:00 2001
From: Steve Purcell <steve@sanityinc.com>
Date: Mon, 3 May 2021 12:54:53 +1200
Subject: [PATCH] lisp/progmodes/ruby-mode.el: puts and printf do not require
 args

Both these methods can be called without arguments, so the font
locking of "bare" calls to either is incorrect.  The fix is to
font-lock them as for other kernel methods which accepts zero or more
arguments.
---
 lisp/progmodes/ruby-mode.el | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lisp/progmodes/ruby-mode.el b/lisp/progmodes/ruby-mode.el
index 35772827ce2..0c54a1d27a6 100644
--- a/lisp/progmodes/ruby-mode.el
+++ b/lisp/progmodes/ruby-mode.el
@@ -2127,11 +2127,9 @@ ruby-font-lock-keywords
           "loop"
           "open"
           "p"
-          "print"
           "printf"
           "proc"
           "putc"
-          "puts"
           "require"
           "require_relative"
           "spawn"
@@ -2180,9 +2178,11 @@ ruby-font-lock-keywords
           "fork"
           "global_variables"
           "local_variables"
+          "print"
           "private"
           "protected"
           "public"
+          "puts"
           "raise"
           "rand"
           "readline"
-- 
2.31.1

bug#48180: ruby-mode.el: fix font lock for puts and printf

[Lars Ingebrigtsen]

Steve Purcell <steve@sanityinc.com> writes:

> Both these methods can be called without arguments, so the font
> locking of "bare" calls to either is incorrect.  The fix is to
> font-lock them as for other kernel methods which accepts zero or more
> arguments.

Thanks; applied to Emacs 28.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#48180: ruby-mode.el: fix font lock for puts and printf

[Dmitry Gutov]

Hi Steve,

On 03.05.2021 04:01, Steve Purcell wrote:
> Both these methods can be called without arguments, so the font
> locking of "bare" calls to either is incorrect.  The fix is to
> font-lock them as for other kernel methods which accepts zero or more
> arguments.

Is that important? Like, is anybody likely to call either without args? 
font-lock is not a precise facility (that anything depends on), so we 
can afford to be wrong in 0.01% cases.

If we institute this principle, I suppose we'll need to do this for all 
functions that can work without args? In my testing, that's also:

p, open, loop, warn, print

Also note that your title says 'printf', but the patch said 'print'.

bug#48180: ruby-mode.el: fix font lock for puts and printf

[Juri Linkov]

>> Both these methods can be called without arguments, so the font
>> locking of "bare" calls to either is incorrect.  The fix is to
>> font-lock them as for other kernel methods which accepts zero or more
>> arguments.
>
> Is that important? Like, is anybody likely to call either without args?
> font-lock is not a precise facility (that anything depends on), so we can
> afford to be wrong in 0.01% cases.

It always bothered me that in ruby-mode highlighting was broken for printing
without arguments, but I had no time to investigate.  Now finally this is fixed.
Maybe some other printing like "p" could be fixed as well, but the
already fixed "puts" and "print" is an improvement.

bug#48180: ruby-mode.el: fix font lock for puts and printf

[Steve Purcell]

On 4 May 2021, at 04:42, Juri Linkov <juri@linkov.net> wrote:
> 
>> Is that important? Like, is anybody likely to call either without args?
>> font-lock is not a precise facility (that anything depends on), so we can
>> afford to be wrong in 0.01% cases.
> 
> It always bothered me that in ruby-mode highlighting was broken for printing
> without arguments, but I had no time to investigate.  Now finally this is fixed.
> Maybe some other printing like "p" could be fixed as well, but the
> already fixed "puts" and "print" is an improvement.


Yes, it’s actually pretty common to just use “puts” without args to print an empty line.

bug#48180: ruby-mode.el: fix font lock for puts and printf

[Dmitry Gutov]

On 03.05.2021 23:31, Steve Purcell wrote:
>> It always bothered me that in ruby-mode highlighting was broken for printing
>> without arguments, but I had no time to investigate.  Now finally this is fixed.
>> Maybe some other printing like "p" could be fixed as well, but the
>> already fixed "puts" and "print" is an improvement.
> 
> Yes, it’s actually pretty common to just use “puts” without args to print an empty line.

Very good, then.