11.58 srfi.226 - Control features ¶

Module: srfi.226 ¶

This srfi enhances the semantics of Scheme’s fundamental concepts such as continuations and dynamic environments, to support multi-threaded programs and delimited continuations. Some R7RS primitives such as call/cc and dynamic-wind are extended to be consistent with the enhanced execution model.

The thread API is mostly compatible with SRFI-18, and so as with Gauche’s thread API (see gauche.threads - Threads).

Since the enhanced features are tightly coupled with runtime, most APIs in this srfi is implemented as built-ins in Gauche. This section gives you the overview of SRFI-226 APIs and pointers to the documents.

In 0.9.13, Gauche only implements part of SRFI-226. We’ll cover its entirety in future releases.

SRFI-226 is an upward compatible extension of R7RS. However, Gauche has also extended R7RS control features in regards of multi-threaded programs, and there are subtle incompatibilites. We’ll move to full SRFI-226 compatibility, but we also provide backward-compatible interface. If you use srfi.226, you’ll get SRFI-226 behavior.

Here’s a list of SRFI-226 APIs and how Gauche supports them.

Continuation prompts

&continuation

make-continuation-violation

continuation-violation?

continuation-violation-prompt-tag

See Conditions

make-continuation-prompt-tag

default-continuation-prompt-tag

continuation-prompt-tag?

call-with-continuation-prompt

abort-current-continuation

See Continuation prompts.

Continuations

call-with-non-comosable-continuation

call-with-composable-continuation

Not implemented yet.

call-with-current-continuation

call/cc

See Continuations.

call-in-continuation

call-in

Not implemented yet.

call-with-continuation-barrier

Not implemented yet.

continuation-prompt-available?

Not implemented yet.

dynamic-wind

See Continuations.

unwind-protect

See High-level exception handling mechanism.

Shift and reset

shift-at

reset-at

Not implemented yet.

shift

reset

See gauche.partcont - Partial continuations. However, current implementation of shift/reset hasn’t integrated to SRFI-226 model yet.

Inspection

continuation?

non-composable-continuation?

Not implemented yet.

Continuation marks

with-continuation-mark

with-continuation-marks

call-with-immediate-continuation-mark

continuation-marks

current-continuation-marks

continuation-mark-set?

continuation-mark-set->list

continuation-mark-set-first

See Continuation marks.

continuation-mark-set->list*

continuation-mark-set->iterator

Not implemented yet.

make-continuation-mark-key

continuation-mark-key?

See Continuation marks.

Parameter objects

make-parameter

make-thread-parameter

See Parameters. Gauche’s built-in make-parameter works in a compatibility mode for now. If you use srfi.226, make-parameter works as specified in SRFI-226.

parameter?

See Parameters.

parameterize

See Parameters. Gauche’s built-in parameterize works in a compatibility mode for now. If you use srfi.226, make-parameter works as specified in SRFI-226.

current-parameterization

parameterization?

call-with-parameterization

See Parameters.

temporarily

See Dynamic states.

Fluids

define-fluid

define-thread-fluid

define-fluidified

fluid-let

fluid-let*

fluid-parameter

Not implemented yet.

Initial continuations

call-with-initial-continuation

Not implemented yet.

Promises

delay

promise?

force

make-promise

See Delay, force and lazy. Gauche’s built-ins are SRFI-226 compatible.

Exceptions

with-exception-handler

current-exception-handler

exception-handler-stack

See Low-level exception handling mechanism. Gauche’s built-ins are SRFI-226 compatible.

raise

raise-continuable

See Signaling exceptions.

guard

See High-level exception handling mechanism.

Conditions

&parameterization

make-parameterization-condition

parameterization-condition?

condition-parameterization

Not implemented yet.

&continuation-marks

make-continuation-marks-condition

continuation-marks-condition?

condition-continuation-marks

Not implemented yet.

&exception-handler-stack

make-exception-handler-stack-condition

exception-handler-stack-condition?

condition-exception-handler-stack

Not implemented yet.

Time objects

time?

current-time

seconds+ time

See Time.

Threads

&thread

make-thread-condition

thread-condition?

&uncaught-exception

make-uncaught-exception

uncaught-exception-condition?

uncaught-exception-condition-reason

&thread-already-terminated

make-thread-already-terminated-condition

thread-already-terminated-condition?

&thread-timeout

make-thread-timeout-condition

thread-timeout-condition?

&thread-abandoned-mutex

make-thread-abandoned-mutex-condition

thread-abandoned-mutex-condition?

&concurrent-modification

make-concurrent-modification-violation

concurrent-modification-violation?

See Thread exceptions.

make-thread

thread?

current-thread

thread-start!

thread-yield!

thread-sleep!

thread-terminate!

thread-schedule-terminate!

thread-join!

See gauche.threads - Threads.

make-mutex

mutex?

mutex-state

mutex-lock!

mutex-unlock!

See Mutex.

make-condition-variable

condition-variable?

condition-variable-signal!

condition-variable-broadcast!

See Condition variable.

make-thread-local

thread-local?

tlref

tlset!

See Thread local storage.

current-interrupt-level

disable-interrupts!

enable-interrupts!

with-interrupts-disabled

with-interrupts-enabled

thread-interrupt!

Not implemented yet.