defpun

See defpun for an introduction.

The following symbols are exported by the lparallel.defpun package as well as by the convenience package lparallel.


[macro]
declaim-defpun &rest names

See `defpun’.

[macro]
defpun name params &body body

`defpun’ defines a function which is specially geared for fine-grained parallelism. If you have many small tasks which bog down the system, `defpun’ may help.

The syntax of `defpun’ matches that of `defun’. The difference is that `plet’ and `plet-if’ take on new meaning inside `defpun’. The symbols in the binding positions of `plet’ and `plet-if’ should be viewed as lazily evaluated immutable references.

Inside a `defpun’ form the name of the function being defined is a macrolet, as are the names of other functions which were defined by `defpun’. Thus using #’ on them is an error. Calls to functions defined by `defpun’ entail more overhead when the caller lies outside a `defpun’ form.

A `defpun’ function must exist before it is referenced inside another `defpun’ function. If this is not possible–for example if func1 and func2 reference each other–then use `declaim-defpun’ to specify intent:

(declaim-defpun func1 func2)

[macro]
defpun/type name params arg-types return-type &body body

Typed version of `defpun’.

`arg-types’ is an unevaluated list of argument types.

`return-type’ is an unevaluated form of the return type, possibly indicating multiple values as in (values fixnum float).

(As a technical point, if `return-type’ contains no lambda list keywords then the return type given to ftype will be additionally constrained to match the number of return values specified.)

[macro]
plet bindings &body body

The syntax of `plet’ matches that of `let’.

plet ({var-no-init | (var [init-form])}*) declaration* form*

For each (var init-form) pair, a future is created which executes `init-form’. Inside `body’, `var’ is a symbol macro which expands to a `force’ form for the corresponding future.

Each `var-no-init’ is bound to nil and each `var’ without `init-form’ is bound to nil (no future is created).

Type declarations for vars are recognized by `plet’ and incorporated into the final expansion. The semantics of these declarations are the same as those of a regular `let’ form.

`plet’ is subject to optimization inside `defpun’.

[macro]
plet-if predicate bindings &body body

The syntax of `plet-if’ matches that of `let’ except for the addition of the `predicate’ form.

If `predicate’ evaluates to true, the behavior is the same as `plet’.

If `predicate’ evaluates to false, the behavior is the same as `let’.

`plet-if’ is subject to optimization inside `defpun’.