:: Text -> Text

O(1) Returns all characters after the head of a Text, which must be non-empty. This is a partial function, consider using uncons instead.

O(1) Returns all but the last character of a Text, which must be non-empty. This is a partial function, consider using unsnoc instead.

O(n) Convert a string to folded case. This function is mainly useful for performing caseless (also known as case insensitive) string comparisons. A string x is a caseless match for a string y if and only if:

toCaseFold x == toCaseFold y

The result string may be longer than the input string, and may differ from applying toLower to the input string. For instance, the Armenian small ligature "ﬓ" (men now, U+FB13) is case folded to the sequence "մ" (men, U+0574) followed by "ն" (now, U+0576), while the Greek "µ" (micro sign, U+00B5) is case folded to "μ" (small letter mu, U+03BC) instead of itself.

O(n) Convert a string to lower case, using simple case conversion. The result string may be longer than the input string. For instance, "İ" (Latin capital letter I with dot above, U+0130) maps to the sequence "i" (Latin small letter i, U+0069) followed by " ̇" (combining dot above, U+0307).

O(n) Convert a string to upper case, using simple case conversion. The result string may be longer than the input string. For instance, the German "ß" (eszett, U+00DF) maps to the two-letter sequence "SS".

O(n) Convert a string to title case, using simple case conversion. The first letter (as determined by isLetter) of the input is converted to title case, as is every subsequent letter that immediately follows a non-letter. Every letter that immediately follows another letter is converted to lower case. This function is not idempotent. Consider lower-case letter ʼn (U+0149 LATIN SMALL LETTER N PRECEDED BY APOSTROPHE). Then toTitle "ʼn" = "ʼN": the first (and the only) letter of the input is converted to title case, becoming two letters. Now ʼ (U+02BC MODIFIER LETTER APOSTROPHE) is a modifier letter and as such is recognised as a letter by isLetter, so toTitle "ʼN" = "'n". The result string may be longer than the input string. For example, the Latin small ligature fl (U+FB02) is converted to the sequence Latin capital letter F (U+0046) followed by Latin small letter l (U+006C). Note: this function does not take language or culture specific rules into account. For instance, in English, different style guides disagree on whether the book name "The Hill of the Red Fox" is correctly title cased—but this function will capitalize every word.

O(n) Remove leading and trailing white space from a string. Equivalent to:

dropAround isSpace

O(n) Remove leading white space from a string. Equivalent to:

dropWhile isSpace

O(n) Remove trailing white space from a string. Equivalent to:

dropWhileEnd isSpace

O(n) Make a distinct copy of the given string, sharing no storage with the original string. As an example, suppose you read a large string, of which you need only a small portion. If you do not use copy, the entire original array will be kept alive in memory by the smaller string. Making a copy "breaks the link" to the original array, allowing it to be garbage collected if there are no other live references to it.

Check the invariant lazily.

O(n/c) Returns all but the last character of a Text, which must be non-empty. This is a partial function, consider using unsnoc instead.

O(n) reverse t returns the elements of t in reverse order.

O(n) Convert a string to folded case. This function is mainly useful for performing caseless (or case insensitive) string comparisons. A string x is a caseless match for a string y if and only if:

toCaseFold x == toCaseFold y

The result string may be longer than the input string, and may differ from applying toLower to the input string. For instance, the Armenian small ligature men now (U+FB13) is case folded to the bigram men now (U+0574 U+0576), while the micro sign (U+00B5) is case folded to the Greek small letter letter mu (U+03BC) instead of itself.

O(n) Convert a string to lower case, using simple case conversion. The result string may be longer than the input string. For instance, the Latin capital letter I with dot above (U+0130) maps to the sequence Latin small letter i (U+0069) followed by combining dot above (U+0307).

O(n) Convert a string to upper case, using simple case conversion. The result string may be longer than the input string. For instance, the German eszett (U+00DF) maps to the two-letter sequence SS.

O(n) Convert a string to title case, using simple case conversion. The first letter (as determined by isLetter) of the input is converted to title case, as is every subsequent letter that immediately follows a non-letter. Every letter that immediately follows another letter is converted to lower case. The result string may be longer than the input string. For example, the Latin small ligature fl (U+FB02) is converted to the sequence Latin capital letter F (U+0046) followed by Latin small letter l (U+006C). This function is not idempotent. Consider lower-case letter ʼn (U+0149 LATIN SMALL LETTER N PRECEDED BY APOSTROPHE). Then toTitle "ʼn" = "ʼN": the first (and the only) letter of the input is converted to title case, becoming two letters. Now ʼ (U+02BC MODIFIER LETTER APOSTROPHE) is a modifier letter and as such is recognised as a letter by isLetter, so toTitle "ʼN" = "'n". Note: this function does not take language or culture specific rules into account. For instance, in English, different style guides disagree on whether the book name "The Hill of the Red Fox" is correctly title cased—but this function will capitalize every word.

cycle ties a finite, non-empty Text into a circular one, or equivalently, the infinite repetition of the original Text.

O(1) A variant of tail for non-empty Text. unsafeTail omits the check for the empty case, so there is an obligation on the programmer to provide a proof that the Text is non-empty.

Wrap double quotes around a Text

Strip trailing newlines from string.

Remove leading and trailing space (including newlines) from string.