Q: Adding Optional option to expression match

[Martin Daser]

Hello *,
I am currently writing a small script to search various patterns within
files.
Therefore I am looping over a bunch of strings and try to find the
pattern. Optionally I want to set a variable to certain flags, which can
be appended to the matching operator. The variable is either empty or
contains some switches/characters.
Adding the variable which holds the switches results in a syntax error:

Scalar found where operator expected at /...../rgrep line 88, near
"m/($word)/$matchopts"
syntax error at /...../rgrep line 88, near "m/($word)/$matchopts"
syntax error at /...../rgrep line 96, near "}"
Execution of /...../rgrep aborted due to compilation errors.

Here is the excerpt to give you an idea:

# set option for ignore case matching; others possible
$matchopts = "i";
.....

# the next line would be line 88
if ($_ =~ m/($word)/$matchopts)
{
.....
}

Is there a way to avoid this error? How can I get around it?

Any help is appreciated! Thanks in advance!

-- Martin

 

[Brian McCauley]

Scalar found where operator expected at /...../rgrep line 88, near
"m/($word)/$matchopts"
syntax error at /...../rgrep line 88, near "m/($word)/$matchopts"
syntax error at /...../rgrep line 96, near "}"
Execution of /...../rgrep aborted due to compilation errors.

Here is the excerpt to give you an idea:

# set option for ignore case matching; others possible
$matchopts = "i";
....

# the next line would be line 88
if ($_ =~ m/($word)/$matchopts)
{
....
}

Is there a way to avoid this error? How can I get around it?

m/((?$matchopts)$word)/

BTW
Why do you say "don't use $_, use $_ instead"?

 

[Martin Daser]

Thanks! that did the job!

m/((?$matchopts)$word)/

BTW
Why do you say "don't use $_, use $_ instead"?