Ada Reference Manual (Ada 2022) — Legal Information
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2.6 String Literals

1
A string_literal is formed by a sequence of graphic characters (possibly none) enclosed between two quotation marks used as string brackets. They are used to represent operator_symbols (see 6.1), values of a string type (see 4.2), and array subaggregates (see 4.3.3).

Syntax

2
string_literal ::= "{string_element}"
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string_element ::= "" | non_quotation_mark_graphic_character
4
A string_element is either a pair of quotation marks (""), or a single graphic_character other than a quotation mark. 

Static Semantics

5
The sequence of characters of a string_literal is formed from the sequence of string_elements between the bracketing quotation marks, in the given order, with a string_element that is "" becoming a single quotation mark in the sequence of characters, and any other string_element being reproduced in the sequence.
6
A null string literal is a string_literal with no string_elements between the quotation marks.
7
NOTE 1   An end of line cannot appear in a string_literal.
7.1/2
NOTE 2   No transformation is performed on the sequence of characters of a string_literal.

Examples

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Examples of string literals: 
9/2
"Message of the day:"

""                    --  a null string literal
" "   "A"   """"      --  three string literals of length 1

"Characters such as $, %, and } are allowed in string literals"
"Archimedes said ""Εύρηκα"""
"Volume of cylinder (πr²h) = "
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