Standard Library

Beyond the core built-ins (Input & Output, string conversions), Lumen ships a small standard library covering strings, files, randomness, and HTTP.

Capabilities

File I/O, random, and HTTP are optional features that a given VM build may or may not implement. See Capabilities for assertCapability and how to check for them.

File I/O

Requires the FS capability.

Function	Description
`openFile path, &handle`	Open a file, storing a handle in `handle`
`writeFile data, handle`	Write a string to an open file
`readFile &out, handle`	Read the full contents of an open file into `out`
`closeFile handle`	Close an open file handle

Random

Requires the random capability.

Function	Description
`randomSeed seed`	Seed the random number generator
`random &out`	Generate a random float in `[0.0, 1.0)` into `out`
`randomRange min, max, &out`	Generate a random integer in `[min, max]` (inclusive) into `out`

HTTP

Requires the HTTP capability.

Function	Description
`httpRequest method, url, headers, body, &status, &response`	Perform an HTTP request

method — 'GET', 'POST', 'PUT', or 'DELETE' (case-insensitive)
url — full URL including scheme, e.g. 'http://example.com/path'
headers — newline-separated Key: Value pairs, or '' for none
body — request body string, ignored for GET
status — receives the HTTP status code, or -1 on a connection-level failure
response — receives the response body, or an error message on failure

HTTPS URLs are not currently supported — only plain http:// requests.

String Manipulation

See Strings for strlen, substr, strfind, strcase, and trim.