A literal represents a value literally, that is, by means of notation suited to its kind. A literal is either a numeric_literal, a character_literal, the literal null, or a string_literal.
Name Resolution Rules
The expected type for a literal null shall be a single access type.
For a name that consists of a character_literal, either its expected type shall be a single character type, in which case it is interpreted as a parameterless function_call that yields the corresponding value of the character type, or its expected profile shall correspond to a parameterless function with a character result type, in which case it is interpreted as the name of the corresponding parameterless function declared as part of the character type's definition (see 3.5.1). In either case, the character_literal denotes the enumeration_literal_specification.
The expected type for a primary that is a string_literal shall be a single string type.
A character_literal that is a name shall correspond to a defining_character_literal of the expected type, or of the result type of the expected profile.
For each character of a string_literal with a given expected string type, there shall be a corresponding defining_character_literal of the component type of the expected string type.
A literal null shall not be of an anonymous access type, since such types do not have a null value (see 3.10).
An integer literal is of type universal_integer. A real literal is of type universal_real.
The evaluation of a numeric literal, or the literal null, yields the represented value.
The evaluation of a string_literal that is a primary yields an array value containing the value of each character of the sequence of characters of the string_literal, as defined in 2.6. The bounds of this array value are determined according to the rules for positional_array_aggregates (see 4.3.3), except that for a null string literal, the upper bound is the predecessor of the lower bound.
For the evaluation of a string_literal of type T, a check is made that the value of each character of the string_literal belongs to the component subtype of T. For the evaluation of a null string literal, a check is made that its lower bound is greater than the lower bound of the base range of the index type. The exception Constraint_Error is raised if either of these checks fails.
6 Enumeration literals that are identifiers rather than character_literals follow the normal rules for identifiers when used in a name (see 4.1 and 4.1.3). Character_literals used as selector_names follow the normal rules for expanded names (see 4.1.3).
Examples of literals:
3.14159_26536 -- a real literal
1_345 -- an integer literal
'A' -- a character literal
"Some Text" -- a string literal
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Copyright © 2000 The MITRE Corporation, Inc. Ada Reference Manual