protocol

text_normalizer_protocol

Text normalization protocol for text represented as atoms, lists of characters, or lists of character codes.

Availability:
logtalk_load(text_normalization(loader))
Author: Paulo Moura
Version: 1:0:0
Date: 2026-09-08
Compilation flags:
static
Dependencies:
(none)
Remarks:
(none)
Inherited public predicates:
(none)

Public predicates

normalize_unicode/3

Normalizes text to the specified Unicode normalization form. Valid forms are nfc, nfd, nfkc, and nfkd.

Compilation flags:
static
Template:
normalize_unicode(Form,Text,Normalized)
Mode and number of proofs:
normalize_unicode(+atom,+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Form is a variable:
instantiation_error
Form is not an atom:
type_error(atom,Form)
Form is not a supported Unicode normalization form:
domain_error(unicode_normalization_form,Form)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

remove_diacritics/2

Canonically decomposes text, removes Unicode mark characters, and returns NFC text.

Compilation flags:
static
Template:
remove_diacritics(Text,Normalized)
Mode and number of proofs:
remove_diacritics(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

fold_diacritics/2

Removes diacritics and applies profile-defined transliterations for characters without canonical decompositions.

Compilation flags:
static
Template:
fold_diacritics(Text,Normalized)
Mode and number of proofs:
fold_diacritics(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

case_fold/2

Applies full default Unicode case folding, unless overridden by the selected profile.

Compilation flags:
static
Template:
case_fold(Text,Folded)
Mode and number of proofs:
case_fold(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

lower_case/2

Converts text to lowercase using the selected profile and Unicode default casing.

Compilation flags:
static
Template:
lower_case(Text,Lowercase)
Mode and number of proofs:
lower_case(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

upper_case/2

Converts text to uppercase using the selected profile and Unicode default casing.

Compilation flags:
static
Template:
upper_case(Text,Uppercase)
Mode and number of proofs:
upper_case(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

title_case/2

Converts text to title case using the library simple word-boundary definition.

Compilation flags:
static
Template:
title_case(Text,Titlecase)
Mode and number of proofs:
title_case(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

decode_entities/2

Decodes semicolon-terminated XML, numeric, and profile-defined named character references using default options.

Compilation flags:
static
Template:
decode_entities(Text,Decoded)
Mode and number of proofs:
decode_entities(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)
A numeric character reference denotes a value that is not a Unicode scalar value:
domain_error(unicode_scalar_value,Value)

decode_entities/3

Decodes semicolon-terminated character references. The recognized option is unknown(preserve|error).

Compilation flags:
static
Template:
decode_entities(Text,Decoded,Options)
Mode and number of proofs:
decode_entities(+text,-text,+list(compound)) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
Options is a variable:
instantiation_error
Options is neither a variable nor a list:
type_error(list,Options)
An element Option of the list Options is a variable:
instantiation_error
An element Option of the list Options is neither a variable nor a compound term:
type_error(compound,Option)
An element Option of the list Options is a compound term but not a valid option:
domain_error(option,Option)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)
A numeric character reference denotes a value that is not a Unicode scalar value:
domain_error(unicode_scalar_value,Value)
A named character reference is unknown and the unknown(error) option is used:
domain_error(character_reference,Reference)

normalize_whitespace/2

Normalizes whitespace using default options.

Compilation flags:
static
Template:
normalize_whitespace(Text,Normalized)
Mode and number of proofs:
normalize_whitespace(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

normalize_whitespace/3

Normalizes whitespace. Recognized options are trim(Boolean), collapse(none|horizontal|all), line_endings(lf|crlf|cr|preserve), and controls(preserve|remove).

Compilation flags:
static
Template:
normalize_whitespace(Text,Normalized,Options)
Mode and number of proofs:
normalize_whitespace(+text,-text,+list(compound)) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
Options is a variable:
instantiation_error
Options is neither a variable nor a list:
type_error(list,Options)
An element Option of the list Options is a variable:
instantiation_error
An element Option of the list Options is neither a variable nor a compound term:
type_error(compound,Option)
An element Option of the list Options is a compound term but not a valid option:
domain_error(option,Option)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)

clean/2

Cleans text using the default normalization pipeline options.

Compilation flags:
static
Template:
clean(Text,Cleaned)
Mode and number of proofs:
clean(+text,-text) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)
A numeric character reference denotes a value that is not a Unicode scalar value:
domain_error(unicode_scalar_value,Value)

clean/3

Cleans text by applying entity decoding, case conversion, diacritic handling, Unicode normalization, and whitespace normalization in that order.

Compilation flags:
static
Template:
clean(Text,Cleaned,Options)
Mode and number of proofs:
clean(+text,-text,+list(compound)) - one_or_error
Exceptions:
The Representation parameter is a variable:
instantiation_error
The Representation parameter is neither a variable nor atom, chars, or codes:
domain_error(text_representation,Representation)
The Profile parameter is a variable:
instantiation_error
The Profile parameter neither a variable nor an object identifier:
type_error(object_identifier,Profile)
The Profile parameter is an object identifier but not an object conforming to text_normalization_profile_protocol:
domain_error(text_normalization_profile,Profile)
Text is not ground:
instantiation_error
The Representation parameter is atom but Text is not an atom:
type_error(atom,Text)
The Representation parameter is chars but Text is not a list of characters:
type_error(chars,Text)
The Representation parameter is codes but Text is not a list of character codes:
type_error(codes,Text)
Options is a variable:
instantiation_error
Options is neither a variable nor a list:
type_error(list,Options)
An element Option of the list Options is a variable:
instantiation_error
An element Option of the list Options is neither a variable nor a compound term:
type_error(compound,Option)
An element Option of the list Options is a compound term but not a valid option:
domain_error(option,Option)
An input character code is not a Unicode scalar value:
domain_error(unicode_scalar_value,Code)
A numeric character reference denotes a value that is not a Unicode scalar value:
domain_error(unicode_scalar_value,Value)
A named character reference is unknown and the unknown_entities(error) option is used:
domain_error(character_reference,Reference)

Protected predicates

(none)

Private predicates

(none)

Operators

(none)

See also

text_normalization_profile_protocol, spelling_normalizer_protocol, text_normalizer(Representation,Profile)