On 09/30/2017 07:59 PM, Brandon Allbery wrote:
On Sat, Sep 30, 2017 at 10:30 PM, ToddAndMargo <toddandma...@zoho.com
<mailto:toddandma...@zoho.com>> wrote:
On 09/30/2017 02:15 PM, Brandon Allbery wrote:
Basically: < > is single quotes and treats variables and
expressions as literals. << >> is double quotes and interpolates
variables but not general expressions. And { } does no quoting
at all and uses general expressions.
This gets a little complex...
1) expressions
2) the difference between "expressions" and "general expressions"
Doublequoted strings don't just expand variables. Postfixes (like [] or
<> to look up values in arrays/hashes) are also understood; method calls
on variables also work, as long as they end with a parenthesized
expression (so, "hi $foo.name <http://foo.name>" will not work (it'll
expand '$foo' instead of '$foo.name <http://foo.name>') but "hi
$foo.name <http://foo.name>()" will, provided $foo contains an object
with a 'name' method). This is what I meant by 'expression', which I
should have probably called 'simple expression' or something.
3) Quoting. The difference between "" and <>
' ' strings and <> postfixes are almost identical. %foo<a> is the same
as %foo{'a'}. But %foo<a b> acts like you did: %foo{'a'}, %foo{'b'}
" " strings and << >> postfixes are almost identical. %foo<<a>> is the
same as %foo{"a"}. But %foo<<a b>> acts like you did: %foo{"a"}, %foo{"b"}
Inside ' ' strings, everything is literal.
Inside " " strings, variables like $foo and (simple) expressions
(described above) will be replaced by their values; and you can use { }
to insert the result of any expression. (This also works in << >>.)
pyanfar Z$ 6 'my %x = ("a"=>"b","c"=>"d", "e"=>"f"); my $v = "b";
say %x<<a {$v.succ}>>'
(b d)
4) "interpolating" as it refers to Perl (not math, where you "guess"
what a value is based on values on both sides of you).
Replacing something inside a string with the string representation of
its value. This sense is also used in documentation for the shell, where
you can also interpolate `` subcommand output and such.
Hi Brandon,
What does the ".succ" do?
Is English your first Language? I asked this because of your use
of the word "interpolate", which you used correctly.
Reference: http://www.wordnik.com/words/interpolate
You used it as to mean "insert":
transitive v. To insert or introduce between other
elements or parts.
As an Engineer, when I use the term, I am using it as:
v. To estimate the value of a function between two
points between which it is tabulated.
And neither one of us are using it as:
transitive v. To change or falsify (a text) by introducing
new or incorrect material.
transitive v. To alter or corrupt by the insertion of new
or foreign matter; especially, to change, as a book or text,
by the insertion of matter that is new, or foreign to
the purpose of the author.
Thank you!
-T
I will be reading your response over several times until is sinks in.
:-)
