Rewrites a JavaScript function or module, such that any global property access is transformed to call a member of a new dsl argument. Use dslify to interpret domain-specific languages without messing around in global scope.
npm install dslify
var dslify = require('dslify')
var script = function() {
return addHorn(addLegs(makeAnimal()))
}
var factory = dslify.transform(script)
var dsl = {
makeAnimal() {
return {}
},
addLegs(animal) {
animal.legs = 4
return animal
},
addHorn(animal) {
animal.horns = 1
return animal
}
}
factory(dsl) // => { legs: 4, horns: 1 }
Sometimes you might want to operate with strings instead of JavaScript functions. For example if you are generating templates or want to send JavaScript to the client.
var dslify = require('dslify')
var input = "function(input) { return shout(input, globalValue) }"
var output = dslify.transform(input, { asString: true })
output // => function(input) { return shout(input, _dsl.globalValue) }
By rewriting an entire module in terms of another 'dsl' interpreter module, you can make slightly larger DSLs:
// abstract.js
module.exports = {
log: function(message) {
print(message);
}
};
// printer.js
module.exports = {
print: function(message) {
console.log(message + '!')
}
};
// compile.js
var dslify = require('dslify');
var abstract = require('fs').readFileSync('./abstract.js', 'utf-8');
var concrete = dslify.transformModule(abstract, './printer');
fs.writeFileSync('./concrete.js', concrete);
// then...
var concrete = require('./concrete.js');
concrete.log('jibber jabber'); // -> jibber jabber!
dslify parses JavaScript using esprima, rewriting it as new JavaScript using escodegen.
Yes. But 'with' is leaky and dangerous, wheras dslify is like a sandbox because it rewrites access to global scope, e.g:
var dslify = require('dslify');
var dsl = {};
var withWith = function(dsl) {
with (dsl) {
y = 'leaks into global!';
}
};
var withDslify = dslify.transform(function() {
z = 'global is safe!';
});
withWith(dsl);
withDslify(dsl);
console.log(global.y); // leaks into global!
console.log(global.z); // undefined
console.log(dsl.z); // global is safe!
Yes. And dynamically generating functions is relatively slow, compared to calling functions. Therefore consider transforming functions at build time instead of run time.
BSD
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