getCustomPragma is split up in more usable chunks

[krux02]

rewrote the customPragma macros for more mudular use.

[Araq]

This needs a [feature] tag and a changelog entry.

[dom96]

Here is the stack trace I get when using this code in my serializer: https://gist.github.com/dom96/af8e3e919d2bb7ed503a4356913faea9

[krux02]

I don't get it. When I run all tests locally, there is one test failing in IC. But when I run category IC only, then there is nothing failing.

output of all tests: http://ix.io/1RkI (fail in category IC)
output of IC only: http://ix.io/1RkQ (success)

Also the CI integration here on the servers tells a very different story.

[planetis-m]

Awesome, finally someone made it a compile time proc instead of a macro. @krux02 <3

[krux02]

@B3liever yes that was the intention.

[krux02]

@Araq, this PR should have been merged long ago.

[Araq]

No RFC process, no explanation what it does. It should have had an explanation a long time ago.

[krux02]

@Araq: This PR enables to read custom pragma annotations from the Nim macro system.

[Clyybber]

I'm taking over

[timotheecour]

@Clyybber IIUC this duplicates the logic in the compiler, which is guaranteed to be fragile; instead why not simply add a magic to avoid duplicating logic and guaranteeing results match what the compiler does?

[zah]

@Clyybber, if you are interested in getting this to work, you might try applying it here:
https://github.com/status-im/nim-serialization/blob/master/serialization/object_serialization.nim#L43-L49

I've found getCustomPragma to be quite broken in real-world usages in generic code, so I've created a different in-house implementation that has a much simpler implementation, but a more cumbersome API.

You can consider getCustomPragma working if the test suite of nim-json-serialization executes sucessfully after the modification.

[Clyybber]

@timotheecour semCustomPragma shares almost no logic with this. The complex parts here are getting to where the pragma actually is.

@zah After 5cde03e it works fine (testsuite of nim-json-serialization passes); I replaced the code snippet you mentioned with

  for fieldName, fieldVar in fieldPairs(obj):
    dumpTree fieldVar
    when not hasCustomPragma(fieldVar, dontSerialize):
      when hasCustomPragma(fieldVar, serializedFieldName):
        const fieldNameVar = getCustomPragmaVal(fieldVar, serializedFieldName)
      else:
        const fieldNameVar = fieldName
      body

[zah]

@Clyybber, nice! Looking forward to start using this in the next release

[disruptek]

Is this going in soon?

[krux02]

Celebrating first anniversary of unmerged but finished PR. Test failure unrelated.

[saem]

Then can we not support it?