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rebolrebol3red-lang

load a map of hash - object key pair

Please consider this example where I save a map! to a file and want to load it back and access its keys and values. Its keys are hashes (INTEGER!, calculated by checksum) and its values are blocks:

Rebol []

bl1: make object! [
        name: "first"
        age: 42
]

bl2: make bl1 []

bl2/name: "second"
bl2/age: 30

hash1: checksum to-binary to-string bl1
hash2: checksum to-binary to-string bl2

m1: make map! []
repend m1 [hash1 bl1]
repend m1 [hash2 bl2]

save %./map_example.ls m1

m2: do load %./map_example.ls
probe join "m2: " type? m2

It returns "m2: map!"

The file %map_example.ls consists of:

make map! [
    2749161 make object! [
        name: "first"
        age: 42
    ]
    4111405 make object! [
        name: "second"
        age: 30
    ]
]

How can I read the map! back to access its keys and values that are objects?

Is foreach a way to go?

Solution

  • SAVE uses an imperfect but more readable format. Use SAVE/ALL to preserve all values exactly as they should be (SAVE/ALL uses so call serialization format in form of #[datatype! value]).

    Also, just use LOAD and not DO LOAD to get the data back. DO is not required in this case - LOAD converts the string to Rebol values and as it's just data, not a script, there's no need to DO it (you can, but it just returns itself).