Files
handlebars.js/lib/handlebars/compiler/visitor.js
T
kpdecker e3d3eda2e1 Add full support for es6
Converts the tool chain to use babel, eslint, and webpack vs. the previous proprietary solutions.

Additionally begins enforcing additional linting concerns as well as updates the code to reflect these rules.

Fixes #855
Fixes #993
2015-04-16 16:43:01 -05:00

120 lines
2.8 KiB
JavaScript

import Exception from '../exception';
import AST from './ast';
function Visitor() {
this.parents = [];
}
Visitor.prototype = {
constructor: Visitor,
mutating: false,
// Visits a given value. If mutating, will replace the value if necessary.
acceptKey: function(node, name) {
var value = this.accept(node[name]);
if (this.mutating) {
// Hacky sanity check:
if (value && (!value.type || !AST[value.type])) {
throw new Exception('Unexpected node type "' + value.type + '" found when accepting ' + name + ' on ' + node.type);
}
node[name] = value;
}
},
// Performs an accept operation with added sanity check to ensure
// required keys are not removed.
acceptRequired: function(node, name) {
this.acceptKey(node, name);
if (!node[name]) {
throw new Exception(node.type + ' requires ' + name);
}
},
// Traverses a given array. If mutating, empty respnses will be removed
// for child elements.
acceptArray: function(array) {
for (var i = 0, l = array.length; i < l; i++) {
this.acceptKey(array, i);
if (!array[i]) {
array.splice(i, 1);
i--;
l--;
}
}
},
accept: function(object) {
if (!object) {
return;
}
if (this.current) {
this.parents.unshift(this.current);
}
this.current = object;
var ret = this[object.type](object);
this.current = this.parents.shift();
if (!this.mutating || ret) {
return ret;
} else if (ret !== false) {
return object;
}
},
Program: function(program) {
this.acceptArray(program.body);
},
MustacheStatement: function(mustache) {
this.acceptRequired(mustache, 'path');
this.acceptArray(mustache.params);
this.acceptKey(mustache, 'hash');
},
BlockStatement: function(block) {
this.acceptRequired(block, 'path');
this.acceptArray(block.params);
this.acceptKey(block, 'hash');
this.acceptKey(block, 'program');
this.acceptKey(block, 'inverse');
},
PartialStatement: function(partial) {
this.acceptRequired(partial, 'name');
this.acceptArray(partial.params);
this.acceptKey(partial, 'hash');
},
ContentStatement: function(/* content */) {},
CommentStatement: function(/* comment */) {},
SubExpression: function(sexpr) {
this.acceptRequired(sexpr, 'path');
this.acceptArray(sexpr.params);
this.acceptKey(sexpr, 'hash');
},
PathExpression: function(/* path */) {},
StringLiteral: function(/* string */) {},
NumberLiteral: function(/* number */) {},
BooleanLiteral: function(/* bool */) {},
UndefinedLiteral: function(/* literal */) {},
NullLiteral: function(/* literal */) {},
Hash: function(hash) {
this.acceptArray(hash.pairs);
},
HashPair: function(pair) {
this.acceptRequired(pair, 'value');
}
};
export default Visitor;