Built-in Modules

These modules are part of the compiler, not the standard library. Every file can use them without a uses line.

String

Function	Description
`length(String) -> Int`	The number of characters, counted as Unicode code points
`concat(String, String) -> String`	Joins two strings
`contains(String, String) -> Bool`	Whether the second string appears in the first
`starts_with(String, String) -> Bool`	Whether the first string starts with the second
`ends_with(String, String) -> Bool`	Whether the first string ends with the second
`slice(String, Int, Int) -> String`	The characters from the start index up to, but not including, the end index
`split(String, String) -> List<String>`	Splits on a separator
`replace(String, String, String) -> String`	Replaces every occurrence of the second string with the third
`trim(String) -> String`	Removes surrounding whitespace
`lowercase(String) -> String`	Lowercase copy
`uppercase(String) -> String`	Uppercase copy
`repeat(String, Int) -> String`	The string repeated a number of times
`charCodeAt(String, Int) -> Int`	The UTF-16 code unit at an index, like JavaScript's `charCodeAt`
`eq(String, String) -> Bool`	Equality, the same as `==`

All of these work with the pipe, since the string comes first: text |> String.trim |> String.lowercase.

Function	Description
`to_string(Int) -> String`	Decimal text
`to_float(Int) -> Float`	The same number as a `Float`
`parse(String) -> Option<Int>`	Reads an integer, or `None` if the text isn't one
`to_base(Int, Int) -> String`	Text in another base: `Int.to_base(5, 2)` is `"101"`
`eq(Int, Int) -> Bool`	Equality, the same as `==`

Function	Description
`to_string(Float) -> String`	Decimal text
`to_int(Float) -> Int`	Drops the fractional part
`floor(Float) -> Float`	Rounds down
`abs(Float) -> Float`	Absolute value
`sqrt(Float) -> Float`	Square root
`sin(Float) -> Float`, `cos(Float) -> Float`	Sine and cosine, in radians
`atan2(Float, Float) -> Float`	The angle of a point, from `y` and `x`
`eq(Float, Float) -> Bool`	Equality, the same as `==`

Std.Math has pi.

Function	Description
`to_string(Bool) -> String`	`"true"` or `"false"`
`eq(Bool, Bool) -> Bool`	Equality, the same as `==`

Function	Description
`info(String) -> {}`	Prints a line to standard output, or `console.log` in the browser
`error(String) -> {}`	Prints a line to standard error, or `console.error` in the browser

Note: Log is not an effect, so pure functions can log. It's meant for output and debugging, not for program logic.