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1583 :: JavaScript objects

• Peter (orginal) [2015-08-26T14:04:08+02:00] view original

  Hello,

  Sorry for (maybe) stupid question, I'm just beginning to play with nim.

  I'm trying to use a small AJAX library https://github.com/flouthoc/minAjax.js in nim-created browser JavaScript. I've created a small wrapper:

  
    type
      minAjaxConf* = object {.exportc.}
        url* : cstring
        rtype* : cstring
        data* : cstring
        success* : cstring
        rmethod* : bool
        debugLog* : cstring
    proc minAjax*(conf : minAjaxConf) {.importc.}
  Run

  In my client.nim I use this wrapper as follows:

  
    var conf : minAjaxConf
    conf.url = "/data"
    conf.rtype = "GET"
    conf.data = ""
    conf.success = "function(data) { printData(data); }"
    conf.debugLog = "true"
    minAjax(conf)
  Run

  And finally I get in compiled client.js:

  var conf_33016 = {url_32005: null, rtype_32006: null, data_32007: null, success_32008: null, rmethod_32009: false, debuglog_32010: null};
    conf_33016.url_32005 = "/data";
    conf_33016.rtype_32006 = "GET";
    conf_33016.data_32007 = "";
    conf_33016.success_32008 = "function(data) { printData(data); }";
    conf_33016.debuglog_32010 = "true";
    minAjax(conf_33016);
  Run

  The problem is that during the compilation to JS, the object member's names are changed, for example url became url_32005! So the library (searching for url, rtype, etc.) does not work.

  How can I fix the names of nim objects compiled to JS objects?

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• yglukhov (orginal) [2015-08-26T15:51:24+02:00] view original

  If you want nim bindings for foreign JS objects, you might want to try this approach:

  type
      minAjaxConf* = ref minAjaxConfObj
      minAjaxConfObj {.importc.} = object
        url* : cstring
        rtype* : cstring
        data* : cstring
        success* : cstring
        rmethod* : bool
        debugLog* : cstring
  let conf = minAjaxConf.new()
  conf.url = "/data"
  # ...
  Run

  When writing bindings to pure JS types, IMHO it's a good practice to give them ref remantics from the start.

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• Peter (orginal) [2015-08-26T17:44:14+02:00] view original

  Why not, but it does not work at all:

  client.nim(21, 25) Error: internal error: genVarInit Traceback (most recent call last) nim.nim(94) nim nim.nim(56) handleCmdLine main.nim(270) mainCommand main.nim(113) commandCompileToJS modules.nim(203) compileProject modules.nim(151) compileModule passes.nim(197) processModule passes.nim(137) processTopLevelStmt jsgen.nim(1714) myProcess jsgen.nim(1704) genModule jsgen.nim(1565) genStmt jsgen.nim(1646) gen jsgen.nim(1565) genStmt jsgen.nim(1676) gen jsgen.nim(1022) genSym jsgen.nim(1555) genProc jsgen.nim(1565) genStmt jsgen.nim(1646) gen jsgen.nim(1565) genStmt jsgen.nim(1652) gen jsgen.nim(1231) genVarStmt jsgen.nim(1202) genVarInit msgs.nim(842) internalError msgs.nim(816) liMessage msgs.nim(715) handleError FAILURE

  on line: let conf = minAjaxConf.new()

  The bindings modified:

  
  type
    minAjaxConf* = ref minAjaxConfObj
    minAjaxConfObj {.importc.} = object
       url* : cstring
       rtype* : cstring
       data* : cstring
       success* : cstring
       rmethod* : bool
       debugLog* : cstring
  Run

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• yglukhov (orginal) [2015-08-26T19:48:45+02:00] view original

  Your code works for me with the devel compiler version. I would suggest using the latest devel for js stuff. My every day starts with a fresh nim pull ;)

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• Peter (orginal) [2015-08-26T22:11:23+02:00] view original

  Thanks, yglukhov! Do object members conserve their names in client.js in your case? I'll try to update nim when I find the procedure of installation of devel version...

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• yglukhov (orginal) [2015-08-26T22:53:52+02:00] view original

  Yes, and basically standard dom.nim module uses the same technique.

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• Peter (orginal) [2015-08-27T11:24:34+02:00] view original

  OK, the devel version of nim compiles well my client.nim and server.nim, object members names are preserved in client.js. Unfortunately, Jester, compiled with this version does not work at all, even a minimalistic example :( I've opened an issue on github for Jester...

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