Source code structure

Front page

Syntax

Literals

Code style

Declarations and assignments

Shadowing

Code organization

Type system

Indentation

Velia uses indentation to delineate blocks.

#main
   print-line(“Block 1”)
   #do
      print-line(“Block 2”)
   print-line(“Block 1 again”)

Comments

Comments start with en-dashes (–) and reach until the end of the line.

Multi-line comments are delimited by en-dashes above and below. They can be nested with additional en-dashes at each delimiter:

– This is a one-line comment.

–
This is a multi-line comment.
It ends with another en-dash on a separate line.

––
This is a nested comment.
––

The outer comment ends here.
–

When a comment appears right before a declaration, it is interpreted as a documentation comment:

– Adds two numbers.
add-2 ← # (x, y) x + y

–
A record type that represents a person.
It has two fields, name and age.
–
person ← #record
   name: string
   age: unsigned-int

Reserved tokens

Keywords always begin with a #. Examples:

#module #main #record #match

This prevents keywords from clashing with regular identifiers.

In addition, Veila uses the following arrows, as well as their ASCII-substitutes, for declarations and assignment. These cannot be used as part of identifiers.

← ⥳ ⥆ <- <~ <+