Strings
Text in East is represent as strings.
String values and type
Strings are dynamically sized and support the full set of unicode characters.
The East type for strings is StringType.
The JavaScript values for StringType are standard strings like "", "abc", etc.
| East type | Example value (JavaScript) | East object notation |
|---|---|---|
StringType | "" | "" |
StringType | "abc" | "abc" |
StringType | "📊📈 Optimize!" | "📊📈 Optimize!" |
Printing values
Values can be printed to strings using the Print function.
This produces output in the "East object notation" style.
For completeness, here is how all the various East types are represented:
| East function | Description | Example usage | Result |
|---|---|---|---|
Print | Print a Boolean | Print(true) | "true" |
Print | Print a integer | Print(1n) | "1" |
Print | Print a float | Print(3.14) | "3.14" |
Print | Print a string | Print("abc") | "\"abc\"" |
Print | Print a date-time | Print(new Date("2023-07-01T12:00:00.000Z")) | "2023-07-01T12:00:00.000" |
Print | Print a null | Print(null) | "null" |
Print | Print a struct | Print({ id: 1n, name: "Alice" }) | "( id=1, name=\"Alice\", )" |
Print | Print a variant | Print(Variant("Circle", 2.5)) | ".Circle 2.5" |
Print | Print an array | Print([1n, 2n, 3n]) | "[ 1, 2, 3, ]" |
Print | Print a set | Print(new Set(["a", "b"])) | "{ \"a\", \"b\", }" |
Print | Print a dictionary | Print(new Map([["a", 1n], ["b", 2n]])) | "{ \"a\": 1, \"b\": 2, }" |
Print | Print a blob | Print(new Uint8Array[1,3,3,7]) | "0x01030307" |
Joining strings and string templates
To build more complex strings the StringJoin function is often employed.
StringJoin will concanate two or more strings together, optionally with a seperator (much like .join on arrays in TypeScript/JavaScript).
It is most often used as a JavaScript
StringJoin`My name is ${name} and my age is ${age}.`
This will automatically construct an East expression that prints the interpolated variables (name and age above) to strings if they are not already, and then stitch together the result.
| East function | Description | Example usage | Result |
|---|---|---|---|
StringJoin | Join values with a seperator | StringJoin(["a", "b"], ".") | "a.b" |
StringJoin | Construct a template string | StringJoin`My name is ${"Alice"}` | "My name is Alice" |
String operations
Strings can be manipulated in a variety of ways, with simple range-based extraction and regular expressions:
| East function | Description | Example usage | Result |
|---|---|---|---|
Substring | Extract a part of a string | Substring("abcdefg", 0, 3) | "abc" |
Lowercase | Replace uppercase characters with lowercase | Lowercase("Abc") | "abc" |
Uppercase | Replace lowercase characters with uppercase | Uppercase("Abc") | "ABC" |
RegexContains | Replace lowercase characters with uppercase | RegexContains("Elara", "lara") | true |
RegexReplace | Replace lowercase characters with uppercase | RegexReplace("Elara", "lara", "LARA") | "ELARA" |
Web helper utilities
The Elara platform is capable of integrating with external web APIs. To aid with this, East provides a range of utility functions for working with URLs and authentication systems.
| East function | Description | Example usage | Result |
|---|---|---|---|
AsciiToBase64 | Encode the bytes of a string as a base64 string | AsciiToBase64("Elara") | "RWxhcmE=" |
Base64ToAscii | Decode a base64 string to construct a string | Base64ToAscii("RWxhcmE=") | "Elara" |
Base64ToHex | Re-encode a base64 string as hexadecimal | Base64ToHex("RWxhcmE=") | "456c617261" |
HexToBase64 | Re-encode a hexadecimal string as base64 | HexToBase64("456c617261") | "RWxhcmE=" |
AsciiToHex | Encode the bytes of a string as a hexadecimal string | AsciiToHex("Elara") | "456c617261" |
HexToAscii | Decode a hexadecmimal string to construct a string | HexToAscii("456c617261") | "Elara" |
URIEncode | Encode a string as a URI path component | URLEncode("two words") | "two%20words" |
URIDecode | Decode a URI path component into a string | URLDecode("two%20words") | "two words" |
Hash | Hash a string with chosen algorithm | Hash("message", "md5", "hex") | "78e731027d8fd50ed642340b7c9a63b3" |
HMAC | Construct a hash-based message authentication code (HMAC) | HMAC("message", "key", "sha256", "base64") | "bp7ym3X//Ft6uuUn1Y/a2y/kLnIZARl2kXNDBl9Y7Uo=" |
Parsing
The Parse function allows you to convert printed values to other East types.
Currently Parse only supports DateTimeType.
| East function | Description | Example usage | Result |
|---|---|---|---|
Parse | Read a value from a string | Parse("2023-07-01T12:00.00.000") | 2023-07-01T12:00.00.000 |
Both Parse and Print support special datetime formatting options.
For more information see
Creating and reading JSON
East also has functions for printing and reading JSON, ToJSON and FromJSON.
| East function | Description | Example usage | Result |
|---|---|---|---|
ToJson | Construct East's canonical JSON representation of a value | ToJson(true) | "true" |
FromJson | Parse a JSON string and construct an East value | FromJson(BooleanType, "true") | true |
A canonical JSON representation is defined every possible value in East.
However the JSON representation is ambiguous, and the type to decode must be specified as the first argument to FromJson.
Ordering
Strings are ordered (by Less, sets, etc) in lexical order, like words in a dictionary.
The order is defined by the unicode values of the characters.
In case that one string is a prefix of another, the shorter string is ordered first.
Representation
String values are represented as standard strings in Elara's canonical JSON representation.
They are printed the same (with double quotes and characters by \ as necessary) in East's object notation generated by Print.
Next steps
Continue to the next tutorial to understand how to use and manipulate date and time with East and Elara.