Rebol [
    Title: "Twhile"
    File: %twhile.r
    Date: 23-Aug-2005/10:32:41+2:00
    Author: "Ladislav Mecir"
]

#include-check %tfunc.r

twhile: tfunc [
    {a transparent while}
    cond-block [block!]
    body-block [block!]
    /local result1 result2 break'
] [
    break': use [break] [
        break: func [[throw] /return value [any-type!]] [
            either return [return' get/any 'value] [exit]
        ]
        'break
    ]
    cond-block: bind/copy cond-block break'
    body-block: bind/copy body-block break'
    result1: true
    error? set/any 'result2 while [
        set/any 'result1 do cond-block
        if not value? 'result1 [
            throw' make error! [script no-return]
        ]
        :result1
    ] body-block
    either :result1 [
        break/return get/any 'result2
    ] [get/any 'result2]
]

comment [
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