String literal

string is zero or more characters written inside single or double quotes.

You can use quotes inside a string, as long as they don't match the quotes surrounding the string:

$var1 = "It's alright"
$var2 = "He is called 'Johnny'"
$var3 = 'He is called "Johnny"'

Single quotes

single quotes allow you to use the syntax of expressions within them.
The @ sign must be placed before the expressions.

item(title = 'windows dir path: @sys.dir')

Double quotes

double quotes allow you to use the Escape Character inside them only.
The backslash (\) escape character turns special characters into characters.
The sequence \" inserts a double quote in a string:

$var1 = "hello\"world"
// result: hello"world

The complete set of escape sequences is as follows:

\'	Single quote
\"	Double quote
\\	Backslash
\0	Null
\a	Alert
\b	Backspace
\f	Form Feed
\n	New Line
\r	Carriage Return
\t	Horizontal Tab
\v	Vertical Tab
\uxxxx	Unicode escape sequence (UTF-16) \uHHHH (range: 0000 - FFFF)
\xnnnn	Unicode escape sequence for character with hex value nnnn (variable length version of \uxxxx)
\Uxxxxxxxx	Unicode escape sequence (UTF-32) \U00HHHHHH (range: 000000 - 10FFFF)

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