sample_lambda.prg

SET PROCEDURE TO promises.prg

CLEAR

=RAND(SECONDS())

LOCAL fun, funthen, funcatch
fun = lambda('(i, counter) => ;;
    m.counter.cntMax = MAX(INT(RAND() * 5000), 1) ;; 
    m.counter.msg = TEXTMERGE("AsyncFunc<<m.i>>: ") ;;
    RETURN AsyncRun(m.counter)')

m.funthen = lambda('(res) => ? TRANSFORM(m.res) + " then " + SYS(2015)')
m.funcatch = lambda('(err) => ? err.Message')

PUBLIC paTasks[1]
LOCAL i
FOR i = 1 TO 100
    DIMENSION paTasks(m.i)
    paTasks[m.i] = AsyncRun(fun, m.i, CREATEOBJECT("Counter"))
    WITH paTasks[m.i]
        .then(m.funthen)
        .catch(m.funcatch)
    ENDWITH
ENDFOR

DEFINE CLASS Counter as Callable
    cnt = 0
    cntMax = 0
    msg = ''
    FUNCTION call
        This.cnt = This.cnt + 1
        IF This.cnt < This.cntMax 
            RETURN AsyncRepeat()
        ENDIF
        RETURN This.msg + TEXTMERGE("counted to <<This.cnt>>")    
    ENDFUNC
ENDDEFINE