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@honix
Last active September 5, 2017 15:24
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Red []
let: func [
binds
block
/local
ctx
][
ctx: context append/only append binds copy [result: do] block
select ctx 'result
]
g: 1
b: 42
let [
a: 100
b: 200
c: b - a
][
a + b + c + g
] ;-- will return 401
b ;-- will return 42 from global context
let [a: 1 b: 2 c: 3] [let [g: 15] [a + b + c + g]] ;-- will return 21
@9214
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9214 commented Aug 23, 2017

let: func [spec src][do bind src context spec]

And regarding wrap, here's the trick:

>> g: 1
>> context [a: 100 b: 200 c: b - a return a + b + c + g]
== 401

@draegtun
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draegtun commented Sep 5, 2017

In Rebol 3 (Ren-C):

>> g: 1
== 1

>> wrap [a: 100 b: 200 c: b - a   a + b + c + g]             
== 401

>> context [a: 100 b: 200 c: b - a  a + b + c + g]       
== make object! [
    [self: a b c]
    [
        a: 100
        b: 200
        c: 100
    ]
]

>> context [a: 100 b: 200 c: b - a return a + b + c + g]
** Script Error: RETURN called with no generator providing it in use
** Where: return construct context
** Near: c + g ??
** File: ../src/core/n-function.c
** Line: 215
ⓘ  Note: use WHY for more error information

CONTEXT should always return an OBJECT! :) Hence why WRAP was added to Rebol 3 (and Ren/C branch went further and disallowed RETURN).

@honix
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honix commented Sep 5, 2017

Updated/clarified 'let

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