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(Special Shell Variables): Autoconf now uses Sed rather than Awk for

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LINENO substitution, and some LINENO bugs have been fixed when using
Sed.
This commit is contained in:
Paul Eggert 2001-10-31 19:26:21 +00:00
parent 4c359a4349
commit cac03a4762
1 changed files with 30 additions and 26 deletions
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56
doc/autoconf.texi
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@ -8190,16 +8190,17 @@ Most modern shells provide the current line number in @code{LINENO}.
Its value is the line number of the beginning of the current command.
Autoconf attempts to execute @command{configure} with a modern shell.
If no such shell is available, it attempts to implement @code{LINENO}
with a simple Awk+Sed prepass that replaces the first instance of the
string @code{$LINENO} in each line with the line's number.
with a Sed prepass that replaces the each instance of the string
@code{$LINENO} (not followed by an alphanumeric character) with the
line's number.
You should not rely on @code{LINENO} within @command{eval}, as the
behavior differs in practice. Also, the possibility of the Awk+Sed
behavior differs in practice. Also, the possibility of the Sed
prepass means that you should not rely on @code{$LINENO} when quoted,
when in here-documents, or when in long commands that cross line
boundaries or that have multiple instances of $LINENO. Subshells
should be OK, though. In the following example, lines 1, 6, and 10
are portable, but the other instances of @code{LINENO} are not:
boundaries. Subshells should be OK, though. In the following
example, lines 1, 6, and 9 are portable, but the other instances of
@code{LINENO} are not:
@example
@group
@ -8211,10 +8212,9 @@ cat <<EOF
EOF
( echo 6. $LINENO )
eval 'echo 7. $LINENO'
echo 8. $LINENO $LINENO
echo 9. '$LINENO'
echo 10. $LINENO '
11.' $LINENO
echo 8. '$LINENO'
echo 9. $LINENO '
10.' $LINENO
@end group
@group
$ @kbd{bash-2.05 lineno}
@ -8223,10 +8223,9 @@ $ @kbd{bash-2.05 lineno}
4. 2
6. 6
7. 1
8. 8 8
9. $LINENO
10. 10
11. 10
8. $LINENO
9. 9
10. 9
@end group
@group
$ @kbd{zsh-3.0.6 lineno}
@ -8235,10 +8234,9 @@ $ @kbd{zsh-3.0.6 lineno}
4. 2
6. 6
7. 7
8. 8 8
9. $LINENO
10. 10
11. 10
8. $LINENO
9. 9
10. 9
@end group
@group
$ @kbd{pdksh-5.2.14 lineno}
@ -8247,15 +8245,22 @@ $ @kbd{pdksh-5.2.14 lineno}
4. 2
6. 6
7. 0
8. 8 8
9. $LINENO
10. 10
11. 10
8. $LINENO
9. 9
10. 9
@end group
@group
$ @kbd{awk '/\$LINENO/@{printf "%d:", NR@}; @{print@}' lineno |}
> @kbd{sed '/\$LINENO/s/^\([^:]*\):\(.*\)\$LINENO/\2\1/' |}
> @kbd{sh}
$ @kbd{sed '=' <lineno |}
> @kbd{ sed '}
> @kbd{ N}
> @kbd{ s,$,-,}
> @kbd{ : loop}
> @kbd{ s,^\([0-9]*\)\(.*\)[$]LINENO\([^a-zA-Z0-9_]\),\1\2\1\3,}
> @kbd{ t loop}
> @kbd{ s,-$,,}
> @kbd{ s,^[0-9]*\n,,}
> @kbd{ ' |}
> @kbd{ sh}
1. 1
3. 3
4. 4
@ -8264,7 +8269,6 @@ $ @kbd{awk '/\$LINENO/@{printf "%d:", NR@}; @{print@}' lineno |}
8. 8
9. 9
10. 10
11. 11
@end group
@end example