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446 | 1
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| var utils = require('../utils');
var Helper = require('./index');
function BackStep(){
this.init.apply(this, arguments);
}
var TRIM = /[\t\n\r]+/g;
BackStep.prototype = {
constructor: BackStep,
init: function(asts, html){
this.context = {};
this.asts = asts;
this.position = -1;
this.html = html.replace(TRIM, '');
this.references = [];
this.local = {};
this.macros = {};
this.conditions = [];
utils.forEach(this.asts, this._trim, this);
this._mergeTree(this.asts);
debugger;
this._render(this.asts);
},
/**
* 合并字符串
*/
_mergeTree: function(asts){
var len = asts.length;
var begin = false;
var end = false;
for (var i = 0; i < len; i++) {
var ast = asts[i];
if (typeof ast === 'string') {
if (begin === false) {
begin = i;
} else {
end = i;
}
} else {
if (begin !== false && end !== false){
for (var j = begin + 1; j <= end; j++) {
asts[begin] += asts[j];
asts[j] = '';
}
}
begin = false;
end = false;
}
asts[i];
}
},
_trim: function(ast, i){
var asts = this.asts;
var _ast = asts[i];
if (typeof _ast === 'string' && _ast.slice(0, 1) === "\n") {
asts[i] = _ast.slice(1);
}
},
_render: function(asts){
var block = [];
var index = 0;
utils.forEach(asts, function(ast){
switch(ast.type) {
case 'references':
if (index) {
block.push(ast);
} else {
this.getReferences(ast);
}
break;
case 'set':
if (index) {
block.push(ast);
} else {
this.setValue(ast);
}
break;
case 'comment':
break;
case 'break':
if (!index){
this.setBreak = true;
} else {
block.push(ast);
}
break;
case 'macro':
case 'if':
case 'foreach':
block.push(ast);
index++;
break;
case 'macro_call':
if (index) {
block.push(ast);
} else {
this.getMacro(ast);
}
break;
case 'end':
index--;
if (!index){
//使用slide获取block的拷贝
this.getBlock(block.slice());
block = [];
} else {
block.push(ast);
}
break;
default:
if (index) {
block.push(ast);
} else {
if (utils.isArray(ast)) {
this.getBlock(ast);
} else {
this.compare(ast);
}
}
break;
// code
}
}, this);
},
compare: function(ast){
if (!ast) return;
var html = this.html;
var position = this.position + 1;
var references = this.references;
ast = ast.replace(TRIM, '').replace(/^\s+|\s+$/g, '');
var index = html.indexOf(ast, position);
//console.log([position, index]);
var text = html.slice(position, index);
if (references.length === 1) {
this.storeValue(references[0], text);
this.references = [];
}
this.position = index + ast.length - 1;
},
getLocal: function(ref){
var ret = this.context;
utils.some(this.conditions, function(content){
var local = this.local[content];
if (local.variable.indexOf(ref.id) > -1){
ret = local.context;
return true;
}
}, this);
return ret;
},
storeValue: function(ref, val){
//var o = this.getLocal(ref);
//var local = o.local;
var context = this.getLocal(ref);
if (!ref.path) {
context[ref.id] = val;
} else {
var baseRef = context[ref.id];
if (typeof baseRef != 'object') {
baseRef = {};
}
context[ref.id] = baseRef;
var len = ref.path ? ref.path.length: 0;
//console.log(val);
utils.forEach(ref.path, function(exp, i){
var isEnd = len === i + 1;
var key = exp.id;
if (exp.type === 'index') key = key.value;
baseRef[key] = isEnd? val: {};
baseRef = baseRef[key];
});
}
},
getBlock: function(block) {
var ast = block[0];
var ret = '';
var _block = [ast];
var _inBlock = [];
var index = 0;
var blockTypes = ['if', 'foreach', 'macro'];
/**
* 处理block嵌套,重新构造_block,把block中有嵌套的放入数组_inBlock,
* _inBlock 最后成为_block的一个元素,_inBlock数组作为一个block数组,求值
* 过程中,可以通过递归求值,进入下一层嵌套
*/
utils.forEach(block, function(ast, i){
if (i) {
if (blockTypes.indexOf(ast.type) !== -1) {
index ++;
_inBlock.push(ast);
} else if (ast.type === 'end') {
index --;
if (index) {
_inBlock.push(ast);
} else {
_block.push(_inBlock.slice());
_inBlock = [];
}
} else {
index ? _inBlock.push(ast) : _block.push(ast);
}
}
});
if (ast.type === 'if') {
ret = this.getBlockIf(_block);
} else if (ast.type === 'foreach') {
ret = this.getBlockEach(_block);
} else if (ast.type === 'macro') {
this.setBlockMacro(_block);
}
return ret;
},
getBlockIf: function(block){
var str = '';
var asts = [];
var condition = block[0].condition;
utils.some(block, function(ast, i){
if (!i) return;
var ret = false;
if (ast.condition || ast.type === 'else') {
if (asts.length) {
ret = this._tryIf(asts, condition);
asts = [];
condition = ast.condition || 'else';
}
} else {
asts.push(ast);
}
return ret;
}, this);
if (asts.length) this._tryIf(asts, condition);
},
_setCondiction: function(condition, value){
var type = condition.type;
var exp= condition.expression;
if (type == 'math') {
//处理一个变量和一个字符串,数字比较
if (exp.length === 2 && exp[0].type === 'references' &&
exp[1].value !== undefined && value) {
var val = this.getExpression(exp[1]);
switch(condition.operator) {
case '==':
this.storeValue(exp[0], value);
break;
case '>':
this.storeValue(exp[0], val + 1);
break;
case '<':
this.storeValue(exp[0], val - 1);
break;
default:
return;
}
}
}
},
_tryIf: function(asts, condition){
var isPass = this.countLoopTimes(asts);
if (isPass) {
this._render(asts);
this._setCondiction(condition, true);
} else {
this._setCondiction(condition, false);
}
return isPass;
},
/**
* define macro
*/
setBlockMacro: function(block){
var ast = block[0];
var _block = block.slice(1);
var macros = this.macros;
macros[ast.id] = {
asts: _block,
args: ast.args
};
},
getBlockEach: function(block){
var ast = block[0];
var guid = utils.guid();
var contextId = 'foreach:' + guid;
var local = {
type: 'foreach',
variable: [ast.to],
context: {}
};
this.local[contextId] = local;
this.conditions.push(contextId);
var asts = block.slice(1);
var times = this.countLoopTimes(asts);
var value = [];
for (var i=0; i < times; i++) {
this._render(asts);
value.push(local.context[ast.to]);
}
this.storeValue(ast.from, value);
this.conditions.pop();
},
/**
* 计算foreach循环次数
*/
countLoopTimes: function(asts){
var html = this.html;
var position = this.position + 1;
var len = html.length;
var ret = 0;
var isOver = false;
var maxTimes = 10000;
var t = 0;
do {
debugger;
t = t + 1;
utils.forEach(asts, function(ast){
if (typeof ast === 'string') {
ast = ast.replace(TRIM, '').replace(/^\s+|\s+$/g, '');
if (!ast) return;
var index = html.indexOf(ast, position);
if (index > -1) {
position = index + ast.length - 1;
} else {
isOver = true;
}
}
if (position > len) isOver = true;
});
if (!isOver) ret = ret + 1;
if (t > maxTimes) {
console.log('Error, max time runed!');
break;
}
} while(!isOver);
return ret;
},
getReferences: function(ast){
this.references.push(ast);
},
getMacro: function(ast){
var macro = this.macros[ast.id];
var guid = utils.guid();
var contextId = 'macro:' + guid;
var local = {
type: 'macro',
variable: this._getArgus(macro.args),
context: {}
};
this.local[contextId] = local;
this.conditions.push(contextId);
this._render(macro.asts);
utils.forEach(macro.args, function(actual, i){
this.storeValue(ast.args[i], local.context[actual.id]);
}, this);
this.conditions.pop();
},
_getArgus: function(args){
var ret = [];
utils.forEach(args, function(arg){
ret.push(arg.id);
});
return ret;
}
};
require('../compile/expression')(BackStep, utils);
require('../compile/literal')(BackStep, utils);
require('../compile/set')(BackStep, utils);
module.exports = BackStep;
|