Get name of node

[donkeyDau]

I'm trying to write a Visitor for the jsleri tree which is returned after parsing. But I got stuck by identifying the exact item. At the moment I get the type (Token, Regex, ...) but not the "name" of the item. Using pyleri the nodes in the tree have names which can easily be accessed by node.element.name. Is the same somehow possible for jsleri? Or do I miss somenthing obvious?

[joente]

Good point, but unfortunately the "name" of the element is not set. There are "onEnter"/"onExit" calls which could be set to each element although I'm not sure that is what you want.

To set the element names, we could implement something like this:

// just as a test, maybe we can make the Grammar constructor to do something
// like this while still being backwards compatible
let setNames = grammar => {
    Object.getOwnPropertyNames(grammar).forEach(name => {
        if (grammar[name] instanceof Jsleri) {
            grammar[name].name = name;
        }
    })
    return grammar;
}

class TestGrammar extends Grammar {
    static kwHi = Keyword('Hi');
    static kwJsleri = Keyword('Jsleri')
    static START = Sequence(this.kwHi, this.kwJsleri);
}

let testGrammar = new (setNames(TestGrammar));

let res = testGrammar.parse('Hi Jsleri')

console.log(res.tree.children[0].element);
// Sequence { args: [..], elements: [..], name: 'START' }

console.log(res.tree.children[0].children[0].element);
// Keyword { args: [ 'Hi' ], keyword: 'Hi', ignCase: false, name: 'kwHi' }

console.log(res.tree.children[0].children[1].element);
// Keyword { args: [ 'Jsleri' ], keyword: 'Jsleri', ignCase: false, name: 'kwJsleri' }

[donkeyDau]

Thank you. That looks exactly what I'm looking for. Unfortunately it seems like babel is not able to work with static properties:

./src/lib/parseCommand.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
SyntaxError: Unexpected token (11:21)

   9 | 
  10 | class MyGrammar extends jsleri.Grammar {
> 11 |   static tParentOpen = jsleri.Token(\'(\', \'tParentOpen\');
     |                      ^
  12 |   static tParentClose = jsleri.Token(\')\', \'tParentClose\');
  13 |   static tCurlyOpen = jsleri.Token(\'{\', \'tCurlyOpen\');
  14 |   static tCurlyClose = jsleri.Token(\'}\', \'tCurlyClose\');

BabelLoaderError: SyntaxError: Unexpected token (11:21)

   9 | 
  10 | class MyGrammar extends jsleri.Grammar {
> 11 |   static tParentOpen = jsleri.Token(\'(\', \'tParentOpen\');
     |                      ^
  12 |   static tParentClose = jsleri.Token(\')\', \'tParentClose\');
  13 |   static tCurlyOpen = jsleri.Token(\'{\', \'tCurlyOpen\');
  14 |   static tCurlyClose = jsleri.Token(\'}\', \'tCurlyClose\');

    at transpile (/app/packages/datawrangler/node_modules/babel-loader/lib/index.js:65:13)
    at Object.module.exports (/app/packages/datawrangler/node_modules/babel-loader/lib/index.js:173:20)

I got around this by defining the Tokens/Keywords/... in the constructor. But then they are not available as Properties, right?

[donkeyDau]

This question on stackOverFlow is dealing with this problem: https://stackoverflow.com/questions/40367392/static-class-property-not-working-with-babel

I'm still using babel 6.x.y But the transform-class-properties plugin requires babel >= 7.0.0. Maybe I find another way around this babel issue...

But besides that: @joente Your proposal looks exactly what I was looking for. Wouldn't it be nice to push that to the master?

[joente]

It probably will work with any Object so I don't think you need to use a class with static class properties.

I think something like this will work (but i did not test the code)

let myGrammar = {};
myGrammar.kwHi = Keyword('Hi');
myGrammar.kwJsleri = Keyword('Jsleri');
myGrammar.START = Sequence(myGrammar.kwHi, myGrammar.kwJsleri);

let compiled = new Grammar(setNames(myGrammar).START);
...

Anyway, I will do some testing, and hope to spend a little time on this issue on Wednesday and merge a working solution to master.

[joente]

Published version 1.1.9 which sets the element names when creating a grammar. (either when using a class or a simple object)