From f26443da0449c459dab8b91d963bd91dd4335657 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Fri, 2 May 2014 13:42:39 -0700 Subject: [PATCH] CodingGuidelines: on splitting a long line Signed-off-by: Junio C Hamano --- Documentation/CodingGuidelines | 55 ++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines index 02ca67c4ca..3d08671ad3 100644 --- a/Documentation/CodingGuidelines +++ b/Documentation/CodingGuidelines @@ -249,6 +249,61 @@ For C programs: Just do not mix styles in the same part of the code and mimic existing styles in the neighbourhood. + - There are two schools of thought when it comes to splitting a long + logical line into multiple lines. Some people push the second and + subsequent lines far enough to the right with tabs and align them: + + if (the_beginning_of_a_very_long_expression_that_has_to || + span_more_than_a_single_line_of || + the_source_text) { + ... + + while other people prefer to align the second and the subsequent + lines with the column immediately inside the opening parenthesis, + with tabs and spaces, following our "tabstop is always a multiple + of 8" convention: + + if (the_beginning_of_a_very_long_expression_that_has_to || + span_more_than_a_single_line_of || + the_source_text) { + ... + + Both are valid, and we use both. Again, just do not mix styles in + the same part of the code and mimic existing styles in the + neighbourhood. + + - When splitting a long logical line, some people change line before + a binary operator, so that the result looks like a parse tree when + you turn your head 90-degrees counterclockwise: + + if (the_beginning_of_a_very_long_expression_that_has_to + || span_more_than_a_single_line_of_the_source_text) { + + while other people prefer to leave the operator at the end of the + line: + + if (the_beginning_of_a_very_long_expression_that_has_to || + span_more_than_a_single_line_of_the_source_text) { + + Both are valid, but we tend to use the latter more, unless the + expression gets fairly complex, in which case the former tends to + be easier to read. Again, just do not mix styles in the same part + of the code and mimic existing styles in the neighbourhood. + + - When splitting a long logical line, with everything else being + equal, it is preferable to split after the operator at higher + level in the parse tree. That is, this is more preferable: + + if (a_very_long_variable * that_is_used_in + + a_very_long_expression) { + ... + + than + + if (a_very_long_variable * + that_is_used_in + a_very_long_expression) { + ... + - Some clever tricks, like using the !! operator with arithmetic constructs, can be extremely confusing to others. Avoid them, unless there is a compelling reason to use them. -- 2.47.1