interface Str2 exposes [ Str2, decimal, split, isEmpty, startsWith, endsWith, contains, anyGraphemes, allGraphemes, join, joinWith, padGraphemesStart, padGraphemesEnd, graphemes, reverseGraphemes, isCaseInsensitiveEq, isCaseInsensitiveNeq, walkGraphemes, isCapitalized, isAllUppercase, isAllLowercase, toUtf8, toUtf16, toUtf32, walkUtf8, walkUtf16, walkUtf32, walkRevUtf8, walkRevUtf16, walkRevUtf32 ] imports [] ## Types ## Dealing with text is a deep topic, so by design, Roc's `Str` module sticks ## to the basics. ## ## _For more advanced use cases like working with raw [code points](https://unicode.org/glossary/#code_point), ## see the [roc/unicode](roc/unicode) package. For locale-specific text ## functions (including uppercasing strings, as capitalization rules vary by locale; ## in English, `"i"` capitalizes to `"I"`, but [in Turkish](https://en.wikipedia.org/wiki/Dotted_and_dotless_I#In_computing), ## the same `"i"` capitalizes to `"Δ°"` - as well as sorting strings, which also varies ## by locale; `"ΓΆ"` is sorted differently in German and Swedish) see the [roc/locale](roc/locale) package._ ## ## ### Unicode ## ## Unicode can represent text values which span multiple languages, symbols, and emoji. ## Here are some valid Roc strings: ## ## "Roc!" ## "鹏" ## "πŸ•Š" ## ## Every Unicode string is a sequence of [extended grapheme clusters](http://www.unicode.org/glossary/#extended_grapheme_cluster). ## An extended grapheme cluster represents what a person reading a string might ## call a "character" - like "A" or "ΓΆ" or "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦". ## Because the term "character" means different things in different areas of ## programming, and "extended grapheme cluster" is a mouthful, in Roc we use the ## term "grapheme" as a shorthand for the more precise "extended grapheme cluster." ## ## You can get the number of graphemes in a string by calling #Str.countGraphemes on it: ## ## Str.countGraphemes "Roc!" ## Str.countGraphemes "ζŠ˜γ‚Šη΄™" ## Str.countGraphemes "πŸ•Š" ## ## > The `countGraphemes` function walks through the entire string to get its answer, ## > so if you want to check whether a string is empty, you'll get much better performance ## > by calling `Str.isEmpty myStr` instead of `Str.countGraphemes myStr == 0`. ## ## ### Escape sequences ## ## If you put a `\` in a Roc string literal, it begins an *escape sequence*. ## An escape sequence is a convenient way to insert certain strings into other strings. ## For example, suppose you write this Roc string: ## ## "I took the one less traveled by,\nAnd that has made all the difference." ## ## The `"\n"` in the middle will insert a line break into this string. There are ## other ways of getting a line break in there, but `"\n"` is the most common. ## ## Another way you could insert a newlines is by writing `\u{0x0A}` instead of `\n`. ## That would result in the same string, because the `\u` escape sequence inserts ## [Unicode code points](https://unicode.org/glossary/#code_point) directly into ## the string. The Unicode code point 10 is a newline, and 10 is `0A` in hexadecimal. ## `0x0A` is a Roc hexadecimal literal, and `\u` escape sequences are always ## followed by a hexadecimal literal inside `{` and `}` like this. ## ## As another example, `"R\u{0x6F}c"` is the same string as `"Roc"`, because ## `"\u{0x6F}"` corresponds to the Unicode code point for lowercase `o`. If you ## want to [spice things up a bit](https://en.wikipedia.org/wiki/Metal_umlaut), ## you can write `"R\u{0xF6}c"` as an alternative way to get the string `"RΓΆc"\. ## ## Roc strings also support these escape sequences: ## ## * `\\` - an actual backslash (writing a single `\` always begins an escape sequence!) ## * `\"` - an actual quotation mark (writing a `"` without a `\` ends the string) ## * `\r` - [carriage return](https://en.wikipedia.org/wiki/Carriage_Return) ## * `\t` - [horizontal tab](https://en.wikipedia.org/wiki/Tab_key#Tab_characters) ## * `\v` - [vertical tab](https://en.wikipedia.org/wiki/Tab_key#Tab_characters) ## ## You can also use escape sequences to insert named strings into other strings, like so: ## ## name = "Lee" ## city = "Roctown" ## ## greeting = "Hello there, \(name)! Welcome to \(city)." ## ## Here, `greeting` will become the string `"Hello there, Lee! Welcome to Roctown."`. ## This is known as [string interpolation](https://en.wikipedia.org/wiki/String_interpolation), ## and you can use it as many times as you like inside a string. The name ## between the parentheses must refer to a `Str` value that is currently in ## scope, and it must be a name - it can't be an arbitrary expression like a function call. ## ## ### Encoding ## ## Roc strings are not coupled to any particular ## [encoding](https://en.wikipedia.org/wiki/Character_encoding). As it happens, ## they are currently encoded in UTF-8, but this module is intentionally designed ## not to rely on that implementation detail so that a future release of Roc can ## potentially change it without breaking existing Roc applications. (UTF-8 ## seems pretty great today, but so did UTF-16 at an earlier point in history.) ## ## This module has functions to can convert a #Str to a #List of raw [code unit](https://unicode.org/glossary/#code_unit) ## integers (not to be confused with the [code points](https://unicode.org/glossary/#code_point) ## mentioned earlier) in a particular encoding. If you need encoding-specific functions, ## you should take a look at the [roc/unicode](roc/unicode) package. ## It has many more tools than this module does! ## A [Unicode](https://unicode.org) text value. ## Str : [ @Str ] ## Convert ## Convert a #Float to a decimal string, rounding off to the given number of decimal places. ## ## Since #Float values are imprecise, it's usually best to limit this to the lowest ## number you can choose that will make sense for what you want to display. ## ## If you want to keep all the digits, passing the same float to #Str.num ## will do that. decimal : Float *, Nat -> Str ## Split a string around a separator. ## ## >>> Str.split "1,2,3" "," ## ## Passing `""` for the separator is not useful; it returns the original string ## wrapped in a list. ## ## >>> Str.split "1,2,3" "" ## ## To split a string into its individual graphemes, use #Str.graphemes split : Str, Str -> List Str ## Check ## Returns #True if the string is empty, and #False otherwise. ## ## >>> Str.isEmpty "hi!" ## ## >>> Str.isEmpty "" isEmpty : Str -> Bool startsWith : Str, Str -> Bool endsWith : Str, Str -> Bool contains : Str, Str -> Bool anyGraphemes : Str, (Str -> Bool) -> Bool allGraphemes : Str, (Str -> Bool) -> Bool ## Combine ## Combine a list of strings into a single string. ## ## >>> Str.join [ "a", "bc", "def" ] join : List Str -> Str ## Combine a list of strings into a single string, with a separator ## string in between each. ## ## >>> Str.joinWith [ "one", "two", "three" ] ", " joinWith : List Str, Str -> Str ## Add to the start of a string until it has at least the given number of ## graphemes. ## ## >>> Str.padGraphemesStart "0" 5 "36" ## ## >>> Str.padGraphemesStart "0" 1 "36" ## ## >>> Str.padGraphemesStart "0" 5 "12345" ## ## >>> Str.padGraphemesStart "✈️"" 5 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦" padGraphemesStart : Str, Int, Str -> Str ## Add to the end of a string until it has at least the given number of ## graphemes. ## ## >>> Str.padGraphemesStart "0" 5 "36" ## ## >>> Str.padGraphemesStart "0" 1 "36" ## ## >>> Str.padGraphemesStart "0" 5 "12345" ## ## >>> Str.padGraphemesStart "✈️"" 5 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦" padGraphemesEnd : Str, Int, Str -> Str ## Graphemes ## Split a string into its individual graphemes. ## ## >>> Str.graphemes "1,2,3" ## ## >>> Str.graphemes "πŸ‘πŸ‘πŸ‘" ## graphemes : Str -> List Str ## Str.countGraphemes "Roc!" # 4 ## Str.countGraphemes "七巧板" # 3 ## Str.countGraphemes "πŸ•Š" # 1 ## Reverse the order of the string's individual graphemes. ## ## >>> Str.reverseGraphemes "1-2-3" ## ## >>> Str.reverseGraphemes "🐦✈️"πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦" ## ## >>> Str.reversegraphemes "CrΓ¨me BrΓ»lΓ©e" reverseGraphemes : Str -> Str ## Returns #True if the two strings are equal when ignoring case. ## ## >>> Str.caseInsensitiveEq "hi" "Hi" isCaseInsensitiveEq : Str, Str -> Bool isCaseInsensitiveNeq : Str, Str -> Bool walkGraphemes : Str, { start: state, step: (state, Str -> state) } -> state ## Returns #True if the string begins with an uppercase letter. ## ## >>> Str.isCapitalized "Hi" ## ## >>> Str.isCapitalized " Hi" ## ## >>> Str.isCapitalized "hi" ## ## >>> Str.isCapitalized "ČeskΓ‘" ## ## >>> Str.isCapitalized "Π­" ## ## >>> Str.isCapitalized "東京" ## ## >>> Str.isCapitalized "🐦" ## ## >>> Str.isCapitalized "" ## ## Since the rules for how to capitalize a string vary by locale, ## (for example, in English, `"i"` capitalizes to `"I"`, but ## [in Turkish](https://en.wikipedia.org/wiki/Dotted_and_dotless_I#In_computing), ## the same `"i"` capitalizes to `"Δ°"`) see the [roc/locale](roc/locale) package ## package for functions which capitalize strings. isCapitalized : Str -> Bool ## Returns #True if the string consists entirely of uppercase letters. ## ## >>> Str.isAllUppercase "hi" ## ## >>> Str.isAllUppercase "Hi" ## ## >>> Str.isAllUppercase "HI" ## ## >>> Str.isAllUppercase " Hi" ## ## >>> Str.isAllUppercase "ČeskΓ‘" ## ## >>> Str.isAllUppercase "Π­" ## ## >>> Str.isAllUppercase "東京" ## ## >>> Str.isAllUppercase "🐦" ## ## >>> Str.isAllUppercase "" isAllUppercase : Str -> Bool ## Returns #True if the string consists entirely of lowercase letters. ## ## >>> Str.isAllLowercase "hi" ## ## >>> Str.isAllLowercase "Hi" ## ## >>> Str.isAllLowercase "HI" ## ## >>> Str.isAllLowercase " Hi" ## ## >>> Str.isAllLowercase "ČeskΓ‘" ## ## >>> Str.isAllLowercase "Π­" ## ## >>> Str.isAllLowercase "東京" ## ## >>> Str.isAllLowercase "🐦" ## ## >>> Str.isAllLowercase "" isAllLowercase : Str -> Bool ## Code Units ## Besides graphemes, another way to break down strings is into ## raw code unit integers. ## ## Code units are no substitute for graphemes! ## These functions exist to support advanced use cases like those found in ## [roc/unicode](roc/unicode), and using code units when graphemes would ## be more appropriate can very easily lead to bugs. ## ## For example, `Str.countGraphemes "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` returns `1`, ## whereas `Str.toUtf8 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` returns a list with a length of 25, ## `Str.toUtf16 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` returns a list with a length of 11. ## and `Str.toUtf32 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` returns a list with a length of 7. ## Return a #List of the string's #U8 UTF-8 [code units](https://unicode.org/glossary/#code_unit). ## (To split the string into a #List of smaller #Str values instead of #U8 values, ## see #Str.split and #Str.graphemes.) ## ## >>> Str.toUtf8 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦" ## ## >>> Str.toUtf8 "Roc" ## ## >>> Str.toUtf8 "鹏" ## ## >>> Str.toUtf8 "🐦" ## ## For a more flexible function that walks through each of these #U8 code units ## without creating a #List, see #Str.walkUtf8 and #Str.walkRevUtf8. toUtf8 : Str -> List U8 ## Return a #List of the string's #U16 UTF-16 [code units](https://unicode.org/glossary/#code_unit). ## (To split the string into a #List of smaller #Str values instead of #U16 values, ## see #Str.split and #Str.graphemes.) ## ## >>> Str.toUtf16 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦" ## ## >>> Str.toUtf16 "Roc" ## ## >>> Str.toUtf16 "鹏" ## ## >>> Str.toUtf16 "🐦" ## ## For a more flexible function that walks through each of these #U16 code units ## without creating a #List, see #Str.walkUtf16 and #Str.walkRevUtf16. toUtf16 : Str -> List U16 ## Return a #List of the string's #U32 UTF-32 [code units](https://unicode.org/glossary/#code_unit). ## (To split the string into a #List of smaller #Str values instead of #U32 values, ## see #Str.split and #Str.graphemes.) ## ## >>> Str.toUtf32 "πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦" ## ## >>> Str.toUtf32 "Roc" ## ## >>> Str.toUtf32 "鹏" ## ## >>> Str.toUtf32 "🐦" ## ## For a more flexible function that walks through each of these #U32 code units ## without creating a #List, see #Str.walkUtf32 and #Str.walkRevUtf32. toUtf32 : Str -> List U32 ## Walk through the string's #U8 UTF-8 [code units](https://unicode.org/glossary/#code_unit) ## to build up a state. ## (If you want a `step` function which receives a #Str instead of an #U8, see #Str.walkGraphemes.) ## ## Here are the #U8 values that will be passed to `step` when this function is ## called on various strings: ## ## * `"πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` passes 240, 159, 145, 169, 226, 128, 141, 240, 159, 145, 169, 226, 128, 141, 240, 159, 145, 166, 226, 128, 141, 240, 159, 145, 166 ## * `"Roc"` passes 82, 111, 99 ## * `"鹏"` passes 233, 185, 143 ## * `"🐦"` passes 240, 159, 144, 166 ## ## To convert a #Str into a plain `List U8` of UTF-8 code units, see #Str.toUtf8. walkUtf8 : Str, { start: state, step: (state, U8 -> state) } -> state ## Walk through the string's #U16 UTF-16 [code units](https://unicode.org/glossary/#code_unit) ## to build up a state. ## (If you want a `step` function which receives a #Str instead of an #U16, see #Str.walkGraphemes.) ## ## Here are the #U16 values that will be passed to `step` when this function is ## called on various strings: ## ## * `"πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` passes 55357, 56425, 8205, 55357, 56425, 8205, 55357, 56422, 8205, 55357, 56422 ## * `"Roc"` passes 82, 111, 99 ## * `"鹏"` passes 40527 ## * `"🐦"` passes 55357, 56358 ## ## To convert a #Str into a plain `List U16` of UTF-16 code units, see #Str.toUtf16. walkUtf16 : Str, { start: state, step: (state, U16 -> state) } -> state ## Walk through the string's #U32 UTF-32 [code units](https://unicode.org/glossary/#code_unit) ## to build up a state. ## (If you want a `step` function which receives a #Str instead of an #U32, see #Str.walkGraphemes.) ## ## Here are the #U32 values that will be passed to `step` when this function is ## called on various strings: ## ## * `"πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` passes 128105, 8205, 128105, 8205, 128102, 8205, 128102 ## * `"Roc"` passes 82, 111, 99 ## * `"鹏"` passes 40527 ## * `"🐦"` passes 128038 ## ## To convert a #Str into a plain `List U32` of UTF-32 code units, see #Str.toUtf32. walkUtf32 : Str, { start: state, step: (state, U32 -> state) } -> state ## Walk backwards through the string's #U8 UTF-8 [code units](https://unicode.org/glossary/#code_unit) ## to build up a state. ## (If you want a `step` function which receives a #Str instead of an #U8, see #Str.walkGraphemes.) ## ## Here are the #U8 values that will be passed to `step` when this function is ## called on various strings: ## ## * `"πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` passes 166, 145, 159, 240, 141, 128, 226, 166, 145, 159, 240, 141, 128, 226, 169, 145, 159, 240, 141, 128, 226, 169, 145, 159, 240 ## * `"Roc"` passes 99, 111, 82 ## * `"鹏"` passes 143, 185, 233 ## * `"🐦"` passes 166, 144, 159, 240 ## ## To convert a #Str into a plain `List U8` of UTF-8 code units, see #Str.toUtf8. walkRevUtf8 : Str, { start: state, step: (state, U8 -> state) } -> state ## Walk backwards through the string's #U16 UTF-16 [code units](https://unicode.org/glossary/#code_unit) ## to build up a state. ## (If you want a `step` function which receives a #Str instead of an #U16, see #Str.walkGraphemes.) ## ## Here are the #U16 values that will be passed to `step` when this function is ## called on various strings: ## ## * `"πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` passes 56422, 55357, 8205, 56422, 55357, 8205, 56425, 55357, 8205, 56425, 55357 ## * `"Roc"` passes 99, 111, 82 ## * `"鹏"` passes 40527 ## * `"🐦"` passes 56358, 55357 ## ## To convert a #Str into a plain `List U16` of UTF-16 code units, see #Str.toUtf16. walkRevUtf16 : Str, { start: state, step: (state, U16 -> state) } -> state ## Walk backwards through the string's #U32 UTF-32 [code units](https://unicode.org/glossary/#code_unit) ## to build up a state. ## (If you want a `step` function which receives a #Str instead of an #U32, see #Str.walkGraphemes.) ## ## Here are the #U32 values that will be passed to `step` when this function is ## called on various strings: ## ## * `"πŸ‘©β€πŸ‘©β€πŸ‘¦β€πŸ‘¦"` passes 128102, 8205, 128102, 8205, 128105, 8205, 128105 ## * `"Roc"` passes 99, 111, 82 ## * `"鹏"` passes 40527 ## * `"🐦"` passes 128038 ## ## To convert a #Str into a plain `List U32` of UTF-32 code units, see #Str.toUtf32. walkRevUtf32 : Str, { start: state, step: (state, U32 -> state) } -> state