compile/call

Symbol: compile/call

Syntax: (CALLEE ARG ...)

Argument specifiers (order matters; analogous to Python 3.5+):

Form	Syntax	Example	Pythonic equivalent
Positional	`EXPR ...`	`(f a b c)`	`f(a, b, c)`
Keyword	`KEY: VAL`	`(f x: 1 y: 2)`	`f(x=1, y=2)`
Star args	`*: EXPR`	`(f *: more)`	`f(*more)`
Star kwargs	`**: EXPR`	`(f **: kwargs)`	`f(**kwargs)`

Positionals may interleave with *: (star args); keywords may interleave with **: (star kwargs). All positionals and *: must come before any keywords or **:; a keyword cannot be followed by *: or a positional. A keyword label written twice in one call is a compile error; a keyword and a **: mapping that name the same key merge at run time, the later one winning. Full form examples:

(fn a b *: more x: xval y: yval **: kwargs)

is equivalent to fn(a, b, *more, x=xval, y=yval, **kwargs) in Python.

(fn a *: bargs c *: dargs)
(fn x: 1 **: kw1 y: 2 **: kw2)

are equivalent to fn(a, *bargs, c, *dargs) and fn(x=1, **kw1, y=2, **kw2) in Python.

Use-case: Generic function application. Evaluates the callee and each argument, then emits CALL (positional only), CALL_NAMES (positional + keywords), or CALL_STAR (any use of *: or **:).

Behaviour: If the callee is (attr OBJ SYM) or (attr OBJ SYM), the form expands to (call-attr OBJ SYM ARGS...) and that form is compiled instead. If the callee is a symbol whose name begins with . and there is at least one argument, the first argument is treated as the receiver OBJ and the remainder as ARGS...; the leading dot is stripped from the callee symbol to obtain SYM, and the form expands to (call-attr OBJ SYM ARGS...) the same way.

Otherwise, compiles the first subform (the callee), then parses the remaining forms with gather_parameters into positionals and star-args (interleaved) and keywords and starstar-args (interleaved). Positional-only calls emit CALL n; keyword calls emit CALL_NAMES; any star or starstar use emits CALL_STAR. Tail-call mode (tc) is respected when set by the compiler.

Examples:

;; Positional
(+ 1 2)
(my-func a b c)

;; Keyword (KEY: VAL)
(fn 1 2 name: "x")

;; Star args (*: EXPR) and star kwargs (**: EXPR)
(apply-fn *: args)
(merge *: pos **: kw)
(fn a b *: rest x: 1 **: extra)

;; Interleaved (Python 3.5+ style)
(fn a *: bargs c *: dargs)
(fn x: 1 **: kw1 y: 2 **: kw2)

;; Method call via attr expansion: ((attr obj m) args) -> compile/call-attr
((attr s upper))
((attr obj split sep) "-")

;; Dot-prefix callee: (.m obj args...) -> compile/call-attr (same as attr)
(.upper s)
(.split s "-")