Date: Wed, 20 Feb 2019 16:51:16 +0000 From: bugzilla-noreply@freebsd.org To: standards@FreeBSD.org Subject: [Bug 235887] awk fails to replace "/ere/" with "$0 ~ /ere/" according to POSIX Message-ID: <bug-235887-99@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=235887 Bug ID: 235887 Summary: awk fails to replace "/ere/" with "$0 ~ /ere/" according to POSIX Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: standards Assignee: standards@FreeBSD.org Reporter: freebsd@tim.thechases.com I've hit a case in which /ere/ doesn't expand the same as "$0 ~ /ere/" which it should do according to the POSIX spec[0]. The goal was to meet the criterion "one and only one of multiple regex matches", so I used jot 20 | awk '/1/ + /5/ == 1' (this can be expanded for any number of expressions, e.g. "/1/ + /5/ + /7/ == 1", but the example using `jot 20` makes it easier to demonstrate the problem, looking for lines containing 1 or 5 but not 15) This gives a parse error: $ jot 20 | awk '/1/ + /5/ == 1' awk: syntax error at source line 1 context is /1/ + >>> / <<< awk: bailing out at source line 1 Strangely, wrapping the expressions in parens works as expected: $ jot 20 | awk '(/1/) + (/5/) == 1' However manually performing the replacement documented above according to the POSIX spec: $ jot 20 | awk '$0 ~ /1/ + $0 ~ /5/ == 1' parses fine (instead of giving the syntax error), so awk isn't doing the "/ere/ -> $0 ~ /ere/" replacement POSIXly. However, this also doesn't give results I'd consider correct (it returns "5" and "15"). Again, wrapping those expansions in parens gives the expected/correct results: $ jot 20 | awk '($0 ~ /1/) + ($0 ~ /5/) == 1' As a side note, gawk parses the original notation ('/1/ + /5/ == 1') fine and it does the same as the parenthesized versions above. -tkc [0] """ When an ERE token appears as an expression in any context other than as the right-hand of the '˜' or "!˜" operator or as one of the built-in function arguments described below, the value of the resulting expression shall be the equivalent of: $0 ˜ /ere/ """ http://pubs.opengroup.org/onlinepubs/009695399/utilities/awk.html -- You are receiving this mail because: You are the assignee for the bug.home | help
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