Meta Comments

Meta comments is a general term for comments whose purpose is to tell some tool something about the code, without actually being part of it. They begin with # @@, followed by a name and content. Each tool reads these separately, so you won't ever get any errors if their names are incorrect.

@@suppress

Suppresses diagnostics (warnings and errors). This is currently only respected by the LSP and CLI. The body consists of a diagnostic id of the form XXX-NNN (where XXX is some string and NNN is a number), and optionally a range specifier.

# Examples of suppressing unused variable warnings

# One line
# @@suppress VAR-3
val a = 1;

# Multiple lines
# @@suppress VAR-3 3 lines
val b = 1;
val c = 2;
val d = 3;

# Region
# @@suppress VAR-3 start
val e = 1;
# @@suppress VAR-3 end

# Whole file
# @@suppress VAR-3 file

@@type

Allows specifying the type of a local variable in cases where inference fails or is insufficient.

# Typing a function:
# @@type (number, number) -> number
function myFunc(a, b) {
    return a + b;
}

# Removing '| unknown' from a mutable variable:
# @@type number
var a = 1;

@@arg

Similar to @@type, but sets the type a named function argument.

# @@arg a number
# @@arg b number
function myFunc(a, b) {
    # LSP knows that a and b are numbers here
}

@@doc_namespace

Sets a default namespace prefix for all following doc entries in a file. If used multiple times the prefix is replaced. If used without a body, this clears the prefix. Does not affect references to other doc entries in types.

# @@doc_namespace my_namespace

#| type MyType: object
#| A type under my_namespace, so it will be called my_namespace.MyType in the

# @@doc_namespace

#| type MyType2: object
#| A type without a namespace, so it will be called MyType2