What is the best way to save a hash! block in Rebol?

Question

I am using Rebol2 and would like to persist a HASH! block.

Currently I am converting it to-string then using save.

Is there a better way? For example:

r: make hash! ["one" "two"]

I want to save this to a file, then load it back to r.

I edited your question a bit...but you can edit it further. Perhaps you might provide some sample data you are interested in, and what you expect when you LOAD it back. — HostileFork says dont trust SE, Nov 30 '19 at 09:23
If you use `save` on a hashed block to a file, it saves it as `make hash! ["one" "two"]` .. ok, but I now want to `load` that back into my program? — Atomica, Dec 01 '19 at 02:03

sqlab · Accepted Answer · 2019-12-02T06:44:33.613

1

you are very near your goal. Just use save/all and load

>> r: make hash! ["one" "two"]
== make hash! ["one" "two"]
>> save/all  %htest r
>> r: load %htest
== make hash! ["one" "two"]

If you want the same result in Red you just need one command more

>> r: do load %htest
== make hash! ["one" "two"]

edited Dec 02 '19 at 06:44

answered Dec 01 '19 at 08:54

sqlab

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That's it! .. In Rebol2 at least.. doesn't work in Red – Atomica Dec 02 '19 at 05:44
You did not add the tag **Red**..) – sqlab Dec 02 '19 at 06:41
One thing Ive manged to do with my code is to keep it compatbile with both Rebol2 and Red. This is the first roadblock. – Atomica Dec 02 '19 at 19:17
If you want the same source for **Red** and **Rebol2** use just `save` and `do load` – sqlab Dec 03 '19 at 07:01

score 0 · Answer 2 · answered Dec 02 '19 at 11:44

0

You do that just like with any other value - save, then load.

There are zero benefits in using hash! for persistent storage, by the way. What load gives you back is a plain block! ([make hash! [...]]). Populating hashtable from this loaded data takes more time compared to just loading block!, but gives you faster lookups thereafter.

In other words, you can just:

>> save %database [one two]
>> make hash! load %database
== make hash! [one two]

As described in the tutorial that you linked.

answered Dec 02 '19 at 11:44

9214

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I'm working with hash! from the start. I'm trying to avoid having to convert to a block or string, then 'saving' it, only to load the block back and hash! it in the process. I don't mind doing that IF it's the better way (faster, smaller db storage) which is the question. save/all seems to avoid this hash! / dehash step. – Atomica Dec 02 '19 at 19:05
@Atomica `save/all` just uses construction syntax to store values and preserves their datatype (+ extra info in specific cases), that's all. `load` still needs to populate hashtable at runtime when you feed it `#[hash! [...]]`, or you need to `do` it manually in case of `[make hash! [...]]`. There are no speed / memory benefits from doing what you do - it's textual data either way (well, storing plain `block!` takes less characters, so it saves you a few bytes). – 9214 Dec 02 '19 at 19:24
Well, in that case, save/all is better as it saves the steps. – Atomica Dec 02 '19 at 19:51

What is the best way to save a hash! block in Rebol?

2 Answers2