add stepper() function and refactor exist range() function for global…

… tags

package.json

@@ -1,6 +1,6 @@
 {
     "name": "gooconverter",
-    "version": "1.0.1",
+    "version": "1.0.3",
     "type": "module",
     "description": "gen string from template",
     "main": "lib/index.cjs",

readme.MD

@@ -16,11 +16,12 @@
 
 `{{表达式}}`
 
-在表达式中还可以使用转换器的唯一内置函数:
+在表达式中还可以使用转换器的内置函数:
 
-`range(start, end, step)`
+- `range(start, end, step)` 产生一个递增或递减的生成器对象，从 start 开始，小于end，步长为 step。
+- `stepper(start, step)` 产生一个递增或递减的步进器，s.next() 步进到下一个值并返回, s.value 为当前值。
 
-参数为整数，输出一个从 start 开始，小于end，步长为 step 的数组。
+非整数时，请注意输出为浮点数，建议输出时用 toFixed(n) 进行格式化。
 
 ### 赋值：
 

src/converter.js

@@ -6,9 +6,7 @@
  * @typedef {Rule[]} Rules Conversion rule table
  */
 
-import {
-    parseToDOM
-} from "./gooparse.js";
+import { parseToDOM } from "./gooparse.js";
 
 /**
  * @param {Tags} tags tags dict for template
@@ -40,22 +38,28 @@ function parseMemberExpression(tags, es_expression) {
 }
 
 const global_tags = {
-    range(...argus) {
+    *range(...argus) {
         let [start, end, step] = argus;
-        if (start === undefined) return [];
+        if (start === undefined) return;
         if (end === undefined) {
             end = start
             start = 0
         }
         const direct = start < end;
         step ??= direct ? 1 : -1;
-        const ret = [];
         let index = start;
         while (direct ? index < end : index > end) {
-            ret.push(index);
+            yield index;
             index += step;
         }
-        return ret;
+    },
+    stepper(init_value = 0, step = 1) {
+        let value = init_value;
+        const next = () => {
+            value += step;
+            return value;
+        }
+        return { value, next }
     },
     Object, Array, Map, Set, // Transparently transmit some system objects
 }
@@ -258,17 +262,18 @@ function computeESExpression(tags, es_expression) {
 function convert_FOR_Goonode(tags, node) {
     let key;
     let value;
-    let list;
+    let iterable;
     let content = '';
     const left = node.expression.left;
     const right = computeESExpression(tags, node.expression.right);
     if (!right) throw Error("wrong for statement!");
-    const isArray = Array.isArray(right);
+    const is_array = Array.isArray(right);
+    const is_iterable = right != null && typeof right[Symbol.iterator] === 'function';
     // {{for v in object}}
     if (left.type === 'Identifier') {
         value = left.name;
-        list = Object.values(right);
-        for (const item of list) {
+        iterable = is_iterable ? right : Object.values(right);
+        for (const item of iterable) {
             content += convert_dom({
                 ...tags,
                 [value]: item
@@ -280,9 +285,9 @@ function convert_FOR_Goonode(tags, node) {
     if (left.type === "ArrayExpression") {
         key = left[0].name;
         value = left[1].name;
-        list = Object.entries(right);
-        for (let [k, v] of list) {
-            k = isArray ? Number.parseInt(k) : k;
+        iterable = Object.entries(is_iterable ? [...right] : right);
+        for (let [k, v] of iterable) {
+            k = is_array ? Number.parseInt(k) : k;
             content += convert_dom({
                 ...tags,
                 [key]: k,

test/test.js

@@ -106,14 +106,22 @@ suite('convert(tags, template)', () => {
                 );
             });
             test('call outputs correctly', () => {
-                strictEqual( // {{ range() }} The output is correct
+                strictEqual( // {{ range() }} outputs correctly
                     convert(
                         {},
-                        '{{range(10)// array}}\n{{for i in range(1,11)}}{{i}} {{endfor}}\n{{for i in range(10,-1,-2)}}{{i}} {{endfor}}'
+                        '{{[...range(10)]// array}}\n{{for i in range(1,11)}}{{i}} {{endfor}}\n{{for i in range(10,8,-0.2)}}{{i.toFixed(1)}} {{endfor}}'
                     ),
-                    "0,1,2,3,4,5,6,7,8,9\n1 2 3 4 5 6 7 8 9 10 \n10 8 6 4 2 0 "
+                    "0,1,2,3,4,5,6,7,8,9\n1 2 3 4 5 6 7 8 9 10 \n10.0 9.8 9.6 9.4 9.2 9.0 8.8 8.6 8.4 8.2 8.0 "
                 );
-                strictEqual( // Object.valueOf Object.entries The output is correct'
+                strictEqual( // {{ stepper() }} outputs correctly
+                    convert(
+                        {},
+                        '{{s = stepper(10,2)}}{{for i in range(1,11)}} {{s.next()}}{{endfor}}\n'
+                        + '{{s = stepper(0,0.1)}}{{for i in range(0,10)}} {{s.next().toFixed(1)}}{{endfor}}'
+                    ),
+                    " 12 14 16 18 20 22 24 26 28 30\n 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0"
+                );
+                strictEqual( // Object.valueOf and Object.entries output correctly
                     convert(
                         { 'myobj': { name: 'myobj', value: 'v' } },
                         '{{myobj.valueOf()}} {{Object.entries(myobj)}}'
@@ -134,7 +142,7 @@ suite('convert(tags, template)', () => {
                     ),
                     "3\n123"
                 );
-                strictEqual( // Custom method output is correct
+                strictEqual( // dustom method outputs correctly
                     convert(
                         {
                             show() {
@@ -213,7 +221,7 @@ suite('convert(tags, template)', () => {
                 );
                 strictEqual(
                     convert(
-                        {list: [1, 2, 3]},
+                        { list: [1, 2, 3] },
                         '{{\n \n// comment\nfor i in list//}}{{i}}{{endfor}}'),
                     "123"
                 );