Syntax

Bridje source is read into forms, the reader’s s-expressions, before anything else sees it. Everything on this page is the reader’s: the sugars are gone by the time the analyser, or a macro, sees the code.

Literals

42, -1

Int — a 64-bit signed integer.

3.14, -0.5

Double — a 64-bit float. A decimal point needs digits either side.

42N

BigInt — an arbitrary-precision integer. n works too.

3.14M, 42M

BigDec — an arbitrary-precision decimal. m works too.

Caution

BigInt and BigDec literals are read, and can be quoted, but aren’t yet supported at runtime.

"hello"

Str. Escapes: \n, \t, \r, \b, \f, \", \\, and \uXXXX with four hex digits; any other escape is an error. There is no string interpolation.

true, false

Bool.

nil

the absent value, of type Nothing?.

Symbols

foo, isEmpty, ->, +

A symbol: a letter or one of * _ + = ? ! < > &, followed by those and digits and -. A symbol may also start with - followed by a non-digit (-1 is an Int), or with # (#, #0 — see anonymous functions).

brj.core, java.time.Instant

A dotted symbol — a namespace or class name.

c/spawn, brj.core/mapv

A qualified symbol: an alias, namespace or class, then /, then a name.

tmp#

A symbol ending in # is an auto-gensym inside a quote.

Members

.name

A member: a record key, or — qualified by an import alias — a host member. See records.

.?name

The optional accessor for the key .name.

m/.name, I/.toEpochMilli

A qualified member: a require alias gives a Bridje key, an import alias a host member.

There is no postfix dot: a.b is a single dotted symbol, not a member access.

Collections

(a b c)

A list — a call, or a special form, when evaluated.

[a b c]

A vector.

#{a b c}

A set.

{.k1 v1 .k2 v2}

A record: members and values, alternating.

Commas are whitespace everywhere: [1, 2, 3] is [1 2 3].

Sugar

f(a, b)

Call syntax. A symbol, qualified symbol or member immediately followed by ( reads as a list with it at the head: (f a b). There must be no whitespace before the (.

Tag{…}

Construction syntax. A symbol or qualified symbol immediately followed by { reads as a call with the braces’ record: Tag{.k v} is (Tag {.k v}).

name: …

A block. A symbol or qualified symbol immediately followed by : opens a list headed by that symbol. It contains every form after the colon on the same line, then every following line indented further than the start of the line the block opened on; the block closes at the first line that isn’t.

def: foo(a, b)
  let: [c add(a, b)]
    mul(c, 2)

reads as (def (foo a b) (let [c (add a b)] (mul c 2))). The colon is the opening parenthesis: (foo: a) reads as ((foo a)). A block opened mid-line takes the rest of that line, so [a fn: f() 1, b 2] puts b 2 inside the fn.

Comments

// …

A line comment. //// is a convention for section headings.

#_ form

Discards the next form, whatever its size.

Metadata

^{.k v} form

Attaches the record to the form, as its static metadata.

^.k form

Shorthand for ^{.k true} form; ^m/.k for a qualified key.

Metadata on a def: is recorded on the var. Several ^s on one form merge.

Quoting

'form

(quote form).

`form

(squote form).

~form

(unquote form).

~@form

(unquoteSplicing form).

See macros and quoting for what they do.