Struct Literal¶

Defined in File Literal.hpp

Inheritance Relationships¶

Base Type¶

public rdf4cpp::Node (Struct Node)

Struct Documentation¶

struct Literal : public rdf4cpp::Node ¶

An RDF Literal.

Functions behave based on the following rules:

public transformation functions (i.e. Literal -> Literal functions, that are usually called as_*) check for null and return back a null literal
public is_* functions check for null and return an appropriate value for null-literals
other public functions (i.e. Literal -> non-Literal) usually do not check for null (e.g. Literal::lexical_form), but if the null-Literal has a meaningful value for that function it will behave correctly (e.g. for null-Literal <=> non-null-Literal)

Public Functions

Literal() noexcept¶: Constructs the null-literal

Literal to_node_storage(storage::DynNodeStoragePtr node_storage) const¶

Literal try_get_in_node_storage(storage::DynNodeStoragePtr node_storage) const noexcept¶

template<datatypes::LiteralDatatype T> inline Literal as_datatype_eq(storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Checks if the datatype of this matches the provided LiteralDatatype

Note

You should prefer this function over comparing datatypes using Literal::datatype

Template Parameters:: T – the datatype to compare against
Returns:: true as xsd:boolean iff this datatype is T or null-literal if this is null

Literal as_datatype_eq(IRI const &datatype, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Checks if the datatype of this matches the given IRI

Note

You should prefer this function over comparing datatypes using Literal::datatype

Parameters:: datatype – the datatype to compare against
Returns:: true as xsd:boolean iff this datatype is datatype or null-literal if this is null

Literal as_datatype_eq(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Checks if the datatype of this matches the datatype of other

Note

You should prefer this function over comparing datatypes using Literal::datatype

Parameters:: other – other literal to check against
Returns:: true as xsd:boolean iff this’ datatype matches other’s datatype or null-literal if this or other is null

Literal cast(IRI const &target, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Tries to cast this literal to a literal of the given type IRI.

Parameters:

target – the IRI of the cast target
node_storage – where to store the literal resulting from the cast

Returns:

the literal with the same value as a different type if the cast was successful or the null literal

template<datatypes::LiteralDatatype T> inline Literal cast(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶: Identical to Literal::cast except with compile time specified target type.

template<datatypes::LiteralDatatype T> requires(!std::same_as< T, datatypes::xsd::String >) std FetchOrSerializeResult fetch_or_serialize_lexical_form (std::string_view &out_lex_form, writer::BufWriterParts writer) const noexcept

Tries to cast this literal to a literal of the given type and return the result without creating a Literal.

Parameters:

out_lex_form – out parameter for the fetched lexical form, is set to the lexical form if function returned FetchOrSerializeResult::Fetched
writer – writer parts to be used if the lexical form is not yet materialized

Returns:

conversion result Returns the lexical from of this. The lexical form is the part of the identifier that encodes the value. So datatype and language_tag are not part of the lexical form.

E.g. For “abc”^^xsd::string the lexical form is abc

Returns:

lexical form Similar to Literal::lexical_form. If the lexical form is already materialized, will return a string_view to it, otherwise serializes it using the given writer.

Returns:

- Fetched, if lexical form was already materialized and could be fetched.

Serialized if lexical form was not yet materialized, but could be serialized.
SerializationFailed if lexical for was not yet materialized, but serialization failed.

Literal as_lexical_form(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Converts this into it’s lexical form as xsd:string. See Literal::lexical_form for more details.

Parameters:: node_storage – where to put the resulting literal
Returns:: lexical form of this as xsd:string if this is not the null literal, otherwise returns the null literal

CowString simplified_lexical_form() const noexcept¶

Returns the simplified/more user friendly string version of this. This is for example used when casting numerics to string.

Returns:: user friendly string representation

FetchOrSerializeResult fetch_or_serialize_simplified_lexical_form(std::string_view &out_lex_form, writer::BufWriterParts writer) const noexcept¶

Similar to Literal::simplified_lexical_form. If the simplified lexical form is already materialized, will return a string_view to it, otherwise serializes it using the given writer.

Parameters:

out_lex_form – out parameter for the fetched lexical form, is set to the lexical form if function returned FetchOrSerializeResult::Fetched
writer – writer parts to be used if the simplified lexical form is not yet materialized

Returns:

- Fetched, if lexical form was already materialized and could be fetched.

Serialized if lexical form was not yet materialized, but could be serialized.
SerializationFailed if lexical for was not yet materialized, but serialization failed.

Literal as_simplified_lexical_form(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Converts this into it’s simplified/more user friendly string representation as xsd:string. See Literal::to_simplified_string for more details.

Returns:: user friendly string representation of this as xsd:string if this is not the null literal, otherwise returns the null literal

IRI datatype() const noexcept¶

Returns the datatype IRI of this.

Returns:: datatype IRI

std::string_view language_tag() const noexcept¶

Returns the language tag of this Literal. If the string is empty this has no language tag.

Returns:: language tag

Literal as_language_tag(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Returns:: the language tag of this Literal as xsd:string. If the string is empty this has no language tag.

TriBool language_tag_eq(std::string_view lang_tag) const noexcept¶

Parameters:: lang_tag – language tag to compare against
Returns:: if this->language_tag() == lang_tag or error if this is not langString

TriBool language_tag_eq(Literal const &other) const noexcept¶

Parameters:

other – literal to compare against

Returns:

if this->language_tag() == other.language_tag() or error if:

this is not rdf:langString
other is not rdf:langString

Literal as_language_tag_eq(std::string_view lang_tag, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:: lang_tag – language tag to compare against
Returns:: if this->language_tag() == lang_tag or null-literal if this is not langString

Literal as_language_tag_eq(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:

other – literal to compare against

Returns:

if this->language_tag() == other.language_tag() or null-literal if:

this is not rdf:langString
other is not rdf:langString

bool serialize(writer::BufWriterParts writer, NodeSerializationOpts opts = NodeSerializationOpts::long_form()) const noexcept¶: See Node::serialize

bool serialize_lexical_form(writer::BufWriterParts writer) const noexcept¶: Serializes this Literal’s canonical lexical form into the decomposed writer See Node::serialize for more details

bool serialize_simplified_lexical_form(writer::BufWriterParts writer) const noexcept¶: Serializes this Literal’s simplified lexical form into the decomposed writer See Node::serialize for more details

explicit operator std::string() const noexcept¶

std::any value() const noexcept¶

Constructs a datatype specific container from Literal.

Returns:: std::any wrapped value. will be empty if type is not registered.

template<datatypes::LiteralDatatype T> inline T::cpp_type value() const¶

Get the value of an literal. T must be the registered datatype for the datatype iri.

Template Parameters:: T – datatype of the returned instance
Returns:: T instance with the value from this

bool is_literal() const noexcept = delete¶

bool is_variable() const noexcept = delete¶

bool is_blank_node() const noexcept = delete¶

bool is_iri() const noexcept = delete¶

bool is_numeric() const noexcept¶

bool is_timepoint() const noexcept¶

bool is_duration() const noexcept¶

std::partial_ordering compare(Literal const &other) const noexcept¶

The literal comparison function for SPARQL filters (FILTER). In contrast to Node, here we can provide a combined “compare” function here because for Literals the definitions of ==/!= and </<=/>/>= are not split in the SPARQL spec.

https://www.w3.org/TR/sparql11-query/#OperatorMapping

std::strong_ordering order(Literal const &other) const noexcept¶

The comparison function for SPARQL orderings (ORDER BY). For FILTER semantics use compare.

Returns:

similar to compare but:

all values of an incomparable type are considered equivalent
a null literal is the smallest possible value of all types
the type ordering replaces the value ordering in the following cases
- the values are equal
- at least one of the value’s types is not comparable
- there is no viable conversion to a common type to check for equality

TriBool eq(Literal const &other) const noexcept¶

bool order_eq(Literal const &other) const noexcept¶

TriBool ne(Literal const &other) const noexcept¶

bool order_ne(Literal const &other) const noexcept¶

TriBool lt(Literal const &other) const noexcept¶

bool order_lt(Literal const &other) const noexcept¶

TriBool le(Literal const &other) const noexcept¶

bool order_le(Literal const &other) const noexcept¶

TriBool gt(Literal const &other) const noexcept¶

bool order_gt(Literal const &other) const noexcept¶

TriBool ge(Literal const &other) const noexcept¶

bool order_ge(Literal const &other) const noexcept¶

Literal as_eq(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_order_eq(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_ne(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_order_ne(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_lt(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_order_lt(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_le(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_order_le(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_gt(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_order_gt(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_ge(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Literal as_order_ge(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

std::partial_ordering operator<=>(Literal const &other) const noexcept¶: Equivalent to this->compare(other)

bool operator==(Literal const &other) const noexcept¶: Equivalent to this->eq(other)

Literal add(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Literal operator+(Literal const &other) const¶

Literal &add_assign(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage)¶

Literal &operator+=(Literal const &other)¶

Literal sub(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Literal operator-(Literal const &other) const¶

Literal &sub_assign(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage)¶

Literal &operator-=(Literal const &other)¶

Literal mul(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Literal operator*(Literal const &other) const¶

Literal &mul_assign(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage)¶

Literal &operator*=(Literal const &other)¶

Literal div(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Literal operator/(Literal const &other) const¶

Literal &div_assign(Literal const &other, storage::DynNodeStoragePtr node_storage = keep_node_storage)¶

Literal &operator/=(Literal const &other)¶

Literal pos(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Literal operator+() const¶

Literal neg(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Literal operator-() const¶

Literal abs(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Returns:: absolute value of this or the null literal if this is not numeric

Literal round(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Returns:: the rounded value of this or the null literal if this is not numeric

Literal floor(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Returns:: the floored value of this or the null literal if this is not numeric

Literal ceil(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Returns:: the ceiled value of this or the null literal if this is not numeric

std::optional<size_t> strlen() const noexcept¶

Returns:: the length this’ lexical form if it is string-like otherwise nullopt

Literal as_strlen(storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Returns:: the length this’ lexical form (as xsd:integer) if it is string-like otherwise the null literal

TriBool language_tag_matches_range(std::string_view lang_range) const noexcept¶

Parameters:: lang_range – a basic language range
Returns:: whether the language tag of this matches the given lang range if this is string-like, otherwise Err

Literal as_language_tag_matches_range(std::string_view lang_range, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:

lang_range – a basic language range as xsd:string

Returns:

whether the language tag of this matches the given lang range or the null literal if

this is not string-like

Literal as_language_tag_matches_range(Literal const &lang_range, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:

lang_range – a basic language range as xsd:string

Returns:

whether the language tag of this matches the given lang range or the null literal if

this is not string-like
lang_range is not xsd:string

TriBool regex_matches(regex::Regex const &pattern) const noexcept¶

Parameters:: pattern – regex to match against
Returns:: whether this’ lexical form matches the regex or Err if this is not string-like

Literal as_regex_matches(regex::Regex const &pattern, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:

pattern – xsd:string containing a regex to match against

Returns:

whether this’ lexical form matches the regex or the null literal if

this is not string-like

Literal as_regex_matches(Literal const &pattern, Literal const &flags = Literal::make_simple(""), storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:

pattern – xsd:string containing a regex to match against
flags – regex flags to use for matching (https://www.w3.org/TR/xpath-functions/#flags)

Returns:

whether this’ lexical form matches the regex or the null literal if

this is not string-like
regex is not string-like
flags is not string-like or not parsable as flags

regex::Regex make_regex(Literal const &flags = Literal::make_simple("")) const¶

Creates a regex, whose pattern is the lexical form of the caller (this->lexical_form())

Parameters:: flags – regex flags to use for matching (https://www.w3.org/TR/xpath-functions/#flags)
Returns:: A regex object (rdf4cpp::regex::Regex)

Literal regex_replace(regex::RegexReplacer const &replacer, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Parameters:: replacer – replacement regex
Returns:: the new string with the matches substring replaced by replacement

Literal regex_replace(Literal const &pattern, Literal const &replacement, Literal const &flags = Literal::make_simple(""), storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Parameters:

pattern – regex (as string) to match against
replacement – string to replace the matched pattern
flags – regex flags to use for matching (https://www.w3.org/TR/xpath-functions/#flags)

Returns:

the new string with the matches substring replaced by replacement

TriBool contains(std::string_view needle) const noexcept¶

Parameters:: needle – substring to search for in this
Returns:: whether this’ lexical form contains the given string or Err if this is not string-like

Literal as_contains(std::string_view needle, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:

needle – substring to search for in this

Returns:

whether this’ lexical form contains the given string (as xsd:boolean) or the null literal if

this is not string-like

Literal as_contains(Literal const &needle, storage::DynNodeStoragePtr node_storage = keep_node_storage) const noexcept¶

Parameters:

needle – substring to search for in this

Returns:

whether this’ lexical form contains the given string (as xsd:boolean) or the null literal if

this is not string-like
needle is not string-like

Literal substr_before(std::string_view needle, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Parameters:

needle – substring to search for in this

Returns:

substring of this’ up to the position of the needle or null literal if

this is not string-like or empty string if
needle is the empty string
needle could not be found in this

Literal substr_before(Literal const &needle, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Parameters:

needle – string-like value to search for in this

Returns:

substring of this’ up to the position of the needle or null literal if

this is not string-like
needle is not string-like or empty string if
needle is the empty string
needle could not be found in this

Literal substr_after(std::string_view needle, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Parameters:

needle – substring to search for in this

Returns:

substring of this’ after the end of the needle or null literal if

this is not string-like or empty string if
needle is the empty string
needle could not be found in this

Literal substr_after(Literal const &needle, storage::DynNodeStoragePtr node_storage = keep_node_storage) const¶

Parameters:

needle – substring to search for in this

Returns:

substring of this’ after the end of the needle or null literal if

this is not string-like
needle is not string-like or empty string if
needle is the empty string
needle could not be found in this

TriBool str_starts_with(std::string_view needle) const noexcept¶

Parameters: