moonscript/docs/standard_lib.md

target: reference/standard_lib
template: reference
title: MoonScript v0.2.0 - Standard Library

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The MoonScript installation comes with a small kernel of functions that can be used to perform various common things.

The entire library is currently contained in a single object. We can bring this moon object into scope by requiring "moon".

require "moon"
-- `moon.p` is the debug printer
moon.p { hello: "world" }

If you prefer to just inject all of the functions into the current scope, you can require "moon.all" instead. The following has the same effect as above:

require "moon.all"
p { hello: "world" }

All of the functions are compatible with Lua in addition to MoonScript, but some of them only make sense in the context of MoonScript.

MoonScript Standard Library

This is an overview of all the included functions. All of the examples assume that the standard library has been included with require "moon.all".

Printing Functions

p(arg)

Prints a formatted version of an object. Excellent for introspecting the contents of a table.

Table Functions

run_with_scope(fn, scope, [args...])

Mutates the environment of function fn and runs the function with any extra args in args.... Returns the result of the function.

The environment of the function is set to a new table whose metatable will use scope to look up values. scope must be a table. If scope does not have an entry for a value, it will fall back on the original environment.

my_env = {
  secret_function: -> print "shhh this is secret"
  say_hi: -> print "hi there!"
}

say_hi = -> print "I am a closure"

fn = ->
  secret_function!
  say_hi!

run_with_scope fn, my_env

Note that any closure values will always take precedence against global name lookups in the environment. In the example above, the say_hi in the environment has been shadowed by the local variable say_hi.

defaultbl([tbl,] fn)

Sets the __index of table tbl to use the function fn to generate table values when a missing key is looked up.

extend

copy

Class/Object Functions

bind_methods

mixin

mixin_object

mixin_table

Misc Functions

fold

Debug Functions

debug.upvalue