Syntax

Files

Source files use the .lcd extension and UTF-8. Each file is one module. The entry file may hold statements at the top level, and they run in order.

print "Hello, world!"

Layout

• A block is indented by exactly four spaces. A tab in indentation is an error.
• A statement ends at the end of its line. There are no semicolons.
• To continue an expression over several lines, wrap it in (), [], or {}. Line breaks inside brackets are ignored. There is no other continuation rule.
• A block starts after a line such as if, for, or task, with no colon.

let primes = [
    2, 3, 5,
    7, 11, 13,
]

for p in primes
    if p > 5
        print p

Comments

Comments start with #. Doc comments start with ##, sit above a declaration, and show in lucid context.

## The area of a circle.
task area(radius: float) -> float
    return 3.14159 * radius * radius   # pi times r squared

print area(2.0)

Names

Names use ASCII letters, digits, and _. By convention, types and variants are UpperCase, and everything else is snake_case. Text and comments may hold any Unicode.

One way to write it

Lucid gives each common job one form, and lucid fmt gives every file one layout, with no options. Code from different people and agents looks the same, and a diff shows only meaning.

There are no macros, no exceptions, no inheritance, no implicit conversions, and no null. Each of these would hide what a line does.

Keywords

and any as break change choice continue else empty expect extern false for if in is let match none not or print public return self shared spawn take task test then trait true try type unsafe use var weak while

shared and weak parse, but do not run yet.