The => operator causes it's left operand to be seen as string as long as it only contains \w-characters and perhaps a leading -minus. The same rules afaik apply for $hash{keys}. In any other position you will get a bareword error from strict, which is in use anyway ;)

Well, it's a bit more complicated. Watch:

#!/bin/sh

for word in 'foo' '-foo' 'foo::bar' '-foo::bar' 'FOO'
do  code='$_ = '$word'; print'
    for  args in ' ' '-w' '-Mstrict' '-Mstrict -w'
    do   cmd="perl $args -le '$code'"
         echo $cmd
         eval $cmd
         echo
    done
done
[download]

Running this gives:

perl -le '$_ = foo; print'
foo

perl -w -le '$_ = foo; print' 
Unquoted string "foo" may clash with future reserved word at -e line 1.
foo
         
perl -Mstrict -le '$_ = foo; print'
Bareword "foo" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.

perl -Mstrict -w -le '$_ = foo; print'
Bareword "foo" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.
 
perl -le '$_ = -foo; print'
-foo
 
perl -w -le '$_ = -foo; print'
-foo
 
perl -Mstrict -le '$_ = -foo; print'
-foo

perl -Mstrict -w -le '$_ = -foo; print'
-foo
         
perl -le '$_ = foo::bar; print'
foo::bar

perl -w -le '$_ = foo::bar; print'
foo::bar

perl -Mstrict -le '$_ = foo::bar; print'
Bareword "foo::bar" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.

perl -Mstrict -w -le '$_ = foo::bar; print'
Bareword "foo::bar" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.
 
perl -le '$_ = -foo::bar; print'
-foo::bar

perl -w -le '$_ = -foo::bar; print'
-foo::bar
         
perl -Mstrict -le '$_ = -foo::bar; print'
-foo::bar

perl -Mstrict -w -le '$_ = -foo::bar; print'
-foo::bar

perl -le '$_ = FOO; print'
FOO

perl -w -le '$_ = FOO; print'
FOO

perl -Mstrict -le '$_ = FOO; print'
Bareword "FOO" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.

perl -Mstrict -w -le '$_ = FOO; print'
Bareword "FOO" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.
         

Interesting, isn't? (And yes, there are good reasons why Perl behaves this way - I won't tell you know, think about it for a while)

Abigail

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