Re: Improving output for single characters (with SmPL)?
From: Markus Elfring
Date: Thu Jul 23 2026 - 15:26:44 EST
> I would like to achieve further source code adjustments by the means of
> the following script variant for the semantic patch language.
Unfortunately, the SmPL code needs to be corrected a bit in the final
replacement rule.
The parameter order should be reversed from selected fprintf() to fputc() calls.
@initialize:python@
@@
input = ''
def convert(item):
mark = ["'", item, "'"]
coccinelle.text = cocci.make_expr(''.join(mark))
def common_checks(unescaped):
if input[1] == '"':
if input[2:] == '':
convert(input[0] if unescaped else '\\' + input[0])
else:
cocci.include_match(False)
else:
cocci.include_match(False)
@find_update_candidate@
constant char[] input_string;
expression input_context;
position pos;
@@
fprintf@pos(input_context, input_string);
@script:python selection@
param << find_update_candidate.input_string;
text;
@@
if param[0] == '"':
input = param[1:]
if input[0] == '\\':
input = input[1:]
if input[0] == '"':
if input[1] == '"':
if input[2:] == '':
convert('"')
else:
cocci.include_match(False)
else:
cocci.include_match(False)
else:
common_checks(False)
else:
common_checks(True)
else:
cocci.include_match(False)
@replacement@
constant char[] find_update_candidate.input_string, selection.text;
expression find_update_candidate.input_context;
position find_update_candidate.pos;
@@
(
-fprintf@pos
+putchar
(
-stdout,
-input_string
+text
)
|
-fprintf@pos
+fputc
(
-input_context
+text
,
-input_string
+input_context
)
)
Another test result (according to the software combination “Coccinelle 1.3.1”):
Markus_Elfring@Sonne:…/Projekte/Linux/next-analyses> time /usr/bin/spatch --timeout 23 -j4 --chunksize 1 --no-loops --include-headers -dir tools …/Projekte/Coccinelle/janitor/use_fputc-20260723.cocci > …/Projekte/Bau/Linux/scripts/Coccinelle/tuning1/next/20260721/use_fputc.diff
…
548 files match
…
real 0m35,324s
user 1m54,532s
sys 0m3,473s
Markus_Elfring@Sonne:/home/altes_Heim2/elfring/Projekte/Linux/next-analyses> lsdiff /home/altes_Heim2/elfring/Projekte/Bau/Linux/scripts/Coccinelle/tuning1/next/20260721/use_fputc.diff | wc -l
50
I hope that demonstrated data processing possibilities can influence further
development ideas in constructive ways besides hints that some compilers
can also perform such a source code transformation already.
Regards,
Markus