Hi Ladislav,
This looks really useful.
A more general use of the behaviour than that of my posts.
But two things.
The name. Why not something more accessible like invoke-path, do-path or
whatever?
Can you explain why the emphasis on referential transparency? Or put another
way, what is a non-referentially transparent way to invoke paths and how
does that differ from your functions?
Brett.
----- Original Message -----
From: "Ladislav Mecir" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 05, 2000 5:06 PM
Subject: [REBOL] Re: Accessing nested Blocks + search in blocks
> Hi,
>
> I hope, that somebody can find some use for the following :
>
> Rebol []
>
> rtp: function [
> {A referentially transparent way to invoke paths}
> [catch]
> block [block!]
> ] [head path stop] [
> path: either stop: find block first [/] [
> copy/part block stop
> ] [
> stop: [none]
> block
> ]
> if not empty? path [
> path: reduce path
> if not word? set/any 'head first path [change/only path 'head]
> if error? path: try [to-path! path] [
> throw make error! {Invalid path representation}
> ]
> ]
> do compose [(:path) (next stop)]
> ]
>
> to-path!: function [
> [catch]
> path-block [block!]
> ] [path] [
> path: make path! length? path-block
> foreach element path-block [
> throw-on-error [
> if :element [insert/only tail :path :element]
> ]
> ]
> :path
> ]
>
> {
> Example:
>
> rtp [now 'time 'second]
> a: [1 2 3]
> rtp [a 1 + 1]
> only: false
> head rtp ['insert if only ['only] / tail a [4]]
> only: true
> head rtp ['insert if only ['only] / tail a [4]]
>
> }
>
>
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