Escape sequences

In an ordinary string literal a backslash is an ordinary character, which is what you want for Windows paths and regular expressions. When you need a tab, a line feed or a character you cannot type, put ! in front of the literal and it reads escape sequences.

'' In an ordinary literal a backslash is just a backslash, and a
'' doubled quote stands for one quote character.
print "C:\tools\new [""quoted""]"

'' Put ! in front and the literal reads escape sequences instead.
print !"tab:[\t] quote:[\"] backslash:[\\]"
print !"two lines:\n  this is the second"

'' Codes in hexadecimal or decimal, and Unicode code points.
print !"\x41\x42 \67 \&h44"
dim as ustring cafe = !"caf\u00E9"
print cafe; " is"; len( cafe ); " characters"

'' \U takes eight hex digits, for code points above U+FFFF.
dim as ustring face = !"\U0001F600"
print "U+1F600 is"; len( face ); " code units"

'' $ in front marks a literal that never reads escapes.
print $"raw: \t \n"

'' A program can build the characters as well as spell them.
print cbool( !"a\tb" = "a" & chr( 9 ) & "b" )

Output

C:\tools\new ["quoted"]
tab:[	] quote:["] backslash:[\]
two lines:
  this is the second
AB C D
café is 4 characters
U+1F600 is 2 code units
raw: \t \n
true

Without a prefix, the only special thing inside quotes is the quote itself: write it twice, "", for one " in the text.

With !, a backslash starts an escape:

A $ prefix marks a literal that never reads escapes. It says the same as no prefix at all, but states it, which is useful in code that also uses ! literals nearby.

\u and \U give you any Unicode character while the source itself stays plain ASCII. A code point above U+FFFF, such as U+1F600, becomes two UTF-16 code units in a ustring, which Unicode explains.

The same escapes work in a block string opened with !""".

Activities

1. Print a three-column table using \t between the columns.
2. Spell the word "naive" with an i-diaeresis, written \u00EF, print it and its len.