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Rebol/Scheduler

Task scheduling library with dialect originally written for Rebol2 by Nenad Rakocevic (Softinnov) in year 2009. Ported to Rebol3 by Oldes.

The original source was downloaded from: https://www.softinnov.org/rebol/scheduler.shtml

Importing the Scheduler

scheduler: import %scheduler.reb

Scheduler DSL quickstart

Legend:

<value> means that the value is optional
CAPITALIZED words design dialect's keywords

Event with a precise point in time :

    <name:> AT time! DO action

Event with a delay :

    <name:> IN n <unit> DO action

Recurring event :

    <name:> EVERY 
        <n> <unit>      ; recurring unit
        <allowed>       ; specific point(s) in time or duration(s) allowed
        <NOT forbidden> ; specific point(s) in time or duration(s) forbidden
        <FROM moment>   ; starting point
        <AT moment>     ; fix time for each event (only date changes)
        <t TIMES>       ; limit the number of event occurences
        DO action       ; job to execute

with

    <name:>:     set-word! value for naming a task (for future access using the API).
    <n>:         integer! value for unit multiplying.
    <unit>:      any of:
                   s|sec|second|seconds
                   mn|minute|minutes
                   h|hour|hours
                   d|day|days
                   w|week|weeks
                   m|month|months
    <allowed>:   any time (00:00:00), calendar day (#dd), weekday (mon|monday), 
                 month (jan|january), range of time|calendar-days or block of any
                 of theses options.
    <forbidden>: same options as <allowed>.
    <moment>:    date! or time! value.
    <t>:         integer! value.
    action:      file!|url!|block!|function!|word! value to be evaluated when event is fired.

Syntactic sugar

Default dialect is parsed in BLOCK! mode. That means that only REBOL values are accepted, but some may want to write calendar dates like: 1st, 2nd,... instead or #1, #2,...

So, a preprocessor is included allowing tasks to be passed as string! values extending the accepted syntax for the following cases:

        1st, 2nd, 3rd,..nth     : accepted
        12s, 12mn, 12h, 12d,... : accepted

Scheduler API

scheduler/plan [spec]      ; add one or more tasks to the scheduler
scheduler/plan/new [spec]  ; same as above but removes all previous tasks
scheduler/delete 'name     ; removes the named task from the scheduler
scheduler/wait             ; provides an adequate global event loop

Examples

scheduler: import %scheduler.reb
scheduler/plan [
    at 18:30 do http://domain.com/update.r3
    every 3 days not [#2 - #9 #12 sat sun] at 00:30 do %batch.r3
    smk: every friday at 13:00 do %test.r3
    cc: every 12 hours do %backup.r3
    every [sat sun] at 12:00 do %beep.r3
    every month on #01 do %check.r3
]
scheduler/wait

(See %test-scheduler.r3 for more examples)