优化：支持显式通过_G来获取全局变量的代码补全；优化：支持string类型变量及字面值字符串的函数补全

server/lib/engine/completion.js

@@ -15,7 +15,7 @@
  ********************************************************************************/
 'use strict';
 
-const { LoadedPackages } = require('./luaenv');
+const { LoadedPackages, _G } = require('./luaenv');
 const { object2Array } = require('./utils');
 const { typeOf, findDef, searchInnerStackIndex } = require('./typeof');
 const { ScopeEnd } = require('./linear-stack');
@@ -34,6 +34,7 @@ class CompletionContext {
         this.range = range;
         this.uri = uri;
         this.functionOnly = expr.endsWith(':');
+        this.isString = false;
     }
 };
 
@@ -87,13 +88,25 @@ function completionProvider(context) {
         value = findDef(name, context.uri, context.range);
     }
 
+    if (context.isString) {
+        value = _G.get('string');
+    }
+
+    if (!value) {
+        return [];
+    }
+
     if (Is.luaFunction(typeOf(value))) {
         if (!value.type.returns) {
             return [];
         }
         value = value.type.returns[0];
     }
 
+    if (Is.luaString(value.type)) {
+        value = _G.get('string');
+    }
+
     if (!Is.luaTable(typeOf(value)) && !Is.luaModule(value)) {
         return [];
     }

server/lib/engine/luaenv.js

@@ -23,6 +23,8 @@ const createTableSymbol = (name, loc, range, local) => {
 
 const _G = createTableSymbol('_G', [0, 3], [0, Infinity], false);
 _G.state = { valid: true };
+_G.set(_G.name, _G);
+
 const LoadedPackages = {};
 
 const global__metatable = createTableSymbol('_G__metatable', [0, 0], [0, Infinity], false);

server/providers/completion-provider.js

@@ -24,6 +24,7 @@ class CompletionProvider {
             }
 
             let ctx = new engine.CompletionContext(ref.name, ref.range, uri);
+            ctx.isString = ref.isString;
             let items = engine.completionProvider(ctx);
             let completionItems = [];
             items.forEach((item, index) => {

server/providers/lib/utils.js

@@ -137,6 +137,7 @@ function bracketMatches(bracketLeft, bracketRight) {
 let rightBracketRegx = /[\)\]\}]/;
 let bracketPairsRegx = /[\(\)\[\]\{\}]/;
 function backward(content, offset, collection) {
+    let isString = false;
     let charIndex = offset;
     let bracketStack = [];
     while (charIndex >= 0) {
@@ -154,6 +155,10 @@ function backward(content, offset, collection) {
             let topChar = bracketStack[bracketStack.length - 1];
             if (topChar == c) {
                 bracketStack.pop();
+                if (bracketStack.length === 0) {
+                    isString = true;
+                    break;
+                }
             } else {
                 bracketStack.push(c);
             }
@@ -199,17 +204,19 @@ function backward(content, offset, collection) {
     }
 
     collection.reverse();
-    return charIndex + 1;
+    return { offset: charIndex + 1, isString };
 }
 
 const forwardRegex = /[a-zA-Z0-9_]/;   // parse only the name
 function extendTextRange(content, from, options) {
-    let range = { start: from, end: from, text: '' };
+    let range = { start: from, end: from, text: '', isString: false };
     let offset = from;
     let collection = [];
     if (options.backward) {
-        offset = backward(content, offset, collection);
-        range.start = offset;
+        let res = backward(content, offset, collection);
+        range.start = res.offset;
+        range.isString = res.isString;
+        offset = res.offset;
     }
 
     if (options.forward) {
@@ -260,7 +267,7 @@ function symbolAtPosition(position, doc, options) {
         return undefined;
     }
 
-    let ref = { name: range.text, range: [range.start, range.end] };
+    let ref = { name: range.text, range: [range.start, range.end], isString: range.isString };
     return ref;
 }
 
@@ -358,7 +365,8 @@ function signatureContext(content, offset) {
     end_pos = skip(/\s/, content, end_pos - 1, -1);
 
     let collection = [];
-    let start_pos = backward(content, end_pos, collection);
+    let res = backward(content, end_pos, collection);
+    let start_pos = res.offset;
     if (start_pos < lower_bound) {
         return undefined;
     }