{"id":10006142,"date":"2022-08-09T00:29:33","date_gmt":"2022-08-08T16:29:33","guid":{"rendered":"https:\/\/ityet.com\/?p=10006142"},"modified":"2022-08-09T00:29:33","modified_gmt":"2022-08-08T16:29:33","slug":"%e7%94%a8-antlr-%e9%87%8d%e6%9e%84%e8%84%9a%e6%9c%ac%e8%a7%a3%e9%87%8a%e5%99%a8","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10006142","title":{"rendered":"\u7528 Antlr \u91cd\u6784\u811a\u672c\u89e3\u91ca\u5668"},"content":{"rendered":"

\u524d\u8a00<\/h2>\n

\u5728\u4e0a\u4e00\u4e2a\u7248\u672c\u5b9e\u73b0\u7684\u811a\u672c\u89e3\u91ca\u5668 GScript<\/a> \u4e2d\u5b9e\u73b0\u4e86\u57fa\u672c\u7684\u56db\u5219\u8fd0\u7b97\u4ee5\u53ca AST<\/code> \u7684\u751f\u6210\u3002<\/p>\n

\"\"<\/p>\n

\u5f53\u6211\u51c6\u5907\u518d\u65b0\u589e\u4e00\u4e2a %<\/code> \u53d6\u6a21\u7684\u8fd0\u7b97\u7b26\u65f6\uff0c\u4f1a\u53d1\u73b0\u5de5\u4f5c\u5f88\u7e41\u7410\u800c\u4e14\u51e0\u4e4e\u90fd\u662f\u91cd\u590d\u7684\uff1b\u4e3b\u8981\u662f\u4e24\u6b65\uff1a<\/p>\n

    \n
  1. \u9700\u8981\u5728\u8bcd\u6cd5\u89e3\u6790\u5668\u4e2d\u65b0\u589e\u5bf9 %<\/code> \u7b26\u53f7\u7684\u652f\u6301\u3002<\/li>\n
  2. \u5728\u8bed\u6cd5\u89e3\u6790\u5668\u904d\u5386 AST \u65f6\u5bf9 %<\/code> token \u5b9e\u73b0\u5177\u4f53\u903b\u8f91\u3002<\/li>\n<\/ol>\n

    \u5176\u4e2d\u7684\u8bcd\u6cd5\u89e3\u6790\u548c\u904d\u5386 AST \u5b8c\u5168\u662f\u91cd\u590d\u5de5\u4f5c\uff0c\u6240\u4ee5\u6211\u4eec\u53ef\u5426\u80fd\u591f\u7b80\u5316\u8fd9\u4e24\u6b65\u5462\uff1f<\/p>\n

    Antlr<\/h2>\n

    Antlr<\/code> \u5c31\u662f\u505a\u5e2e\u6211\u4eec\u89e3\u51b3\u8fd9\u4e9b\u95ee\u9898\u7684\u5e38\u7528\u5de5\u5177\uff0c\u5229\u7528\u5b83\u6211\u4eec\u53ea\u9700\u8981\u7f16\u5199\u8bcd\u6cd5\u6587\u4ef6\uff0c\u7136\u540e\u5c31\u53ef\u4ee5\u81ea\u52a8\u751f\u6210\u8bcd\u6cd5\u3001\u8bed\u6cd5\u89e3\u6790\u5668\uff0c\u5e76\u4e14\u53ef\u4ee5\u751f\u6210\u4e0d\u540c\u8bed\u8a00\u7684\u4ee3\u7801\u3002<\/p>\n

    \u4e0b\u9762\u4ee5 GScript<\/code> \u7684\u793a\u4f8b\u6765\u770b\u770b antlr \u662f\u5982\u4f55\u5e2e\u6211\u4eec\u751f\u6210\u8bcd\u6cd5\u5206\u6790\u5668\u7684\u3002<\/p>\n

    func TestGScriptVisitor_Visit_Lexer(t *testing.T) {\n    expression := "(2+3) * 2"\n    input := antlr.NewInputStream(expression)\n    lexer := parser.NewGScriptLexer(input)\n    for {\n        t := lexer.NextToken()\n        if t.GetTokenType() == antlr.TokenEOF {\n            break\n        }\n        fmt.Printf("%s (%q) %d\/n",\n            lexer.SymbolicNames[t.GetTokenType()], t.GetText(),t.GetColumn())\n    }\n}<\/code><\/pre>\n
    \/\/output:\n ("(") 0\nDECIMAL_LITERAL ("2") 1\nPLUS ("+") 2\nDECIMAL_LITERAL ("3") 3\n (")") 4\nMULT ("*") 6\nDECIMAL_LITERAL ("2") 8<\/code><\/pre>\n
    Antlr <\/code> \u4f1a\u81ea\u52a8\u5c06\u6211\u4eec\u7684\u8868\u8fbe\u5f0f\u89e3\u6790\u4e3a token<\/code>\uff0c\u904d\u5386 token<\/code> \u65f6\u8fd8\u80fd\u62ff\u5230\u8be5 token<\/code> \u6240\u5728\u7684\u4ee3\u7801\u884c\u6570\u3001\u4f4d\u7f6e\u7b49\u4fe1\u606f\uff0c\u5728\u7f16\u8bd1\u671f\u95f4\u505a\u8bed\u6cd5\u68c0\u67e5\u975e\u5e38\u6709\u7528\u3002<\/p>\n
    \u8981\u5b9e\u73b0\u8fd9\u4e9b\u6211\u4eec\u53ea\u9700\u8981\u7f16\u5199\u8bcd\u6cd5\u3001\u8bed\u6cd5\u89c4\u5219\u6587\u4ef6\u5373\u53ef\u3002<\/p>\n
    \u521a\u624d\u7684\u793a\u4f8b\u6240\u5bf9\u5e94\u7684\u8bcd\u6cd5\u3001\u8bed\u6cd5\u89c4\u5219\u5982\u4e0b\uff1a<\/p>\n
    expr\n    : '(' expr ')'                        #NestedExpr\n    | liter=literal #Liter\n    | lhs=expr bop=( MULT | DIV ) rhs=expr #MultDivExpr\n    | lhs=expr bop=MOD rhs=expr            #ModExpr\n    | lhs=expr bop=( PLUS | SUB ) rhs=expr #PlusSubExpr\n    | expr bop=(LE | GE | GT | LT ) expr # GLe\n    | expr bop=(EQUAL | NOTEQUAL) expr # EqualOrNot\n    ;\nDECIMAL_LITERAL:    ('0' | [1-9] (Digits? | '_'+ Digits)) [lL]?;    <\/code><\/pre>\n
    \u5b8c\u6574\u89c4\u5219\uff1ahttps:\/\/github.com\/crossoverJie\/gscript\/blob\/main\/GScript.g4<\/a><\/p><\/blockquote>\n
    \u8fd0\u884c\uff1a<\/p>\n
    antlr -Dlanguage=Go -o parser -visitor -no-listener GScript.g4<\/code><\/pre>\n
    \u5c31\u53ef\u4ee5\u5e2e\u6211\u4eec\u751f\u6210 Go<\/code> \u7684\u4ee3\u7801\uff08\u9ed8\u8ba4\u662f Java<\/code>\uff09\uff0c\u5173\u4e8e Antlr<\/code> \u7684\u8bcd\u6cd5\u3001\u6587\u6cd5\u89c4\u5219\u4ee5\u53ca\u5b89\u88c5\u6b65\u9aa4\u8bf7\u53c2\u8003\u5b98\u7f51<\/a>\u3002<\/p>\n
    \u800c\u6211\u4eec\u8981\u5b9e\u73b0\u5177\u4f53\u7684\u8bed\u6cd5\u903b\u8f91\u65f6\u53ea\u9700\u8981\u5b9e\u73b0\u76f8\u5173\u7684\u63a5\u53e3\uff0cAntlr<\/code> \u4f1a\u81ea\u52a8\u904d\u5386 AST<\/code>\uff08\u5f53\u7136\u4e5f\u53ef\u4ee5\u624b\u52a8\u63a7\u5236\uff09\uff0c\u540c\u65f6\u5728\u8bbf\u95ee\u4e0d\u540c\u7684 AST<\/code> \u8282\u70b9\u65f6\u4f1a\u56de\u8c03\u6211\u4eec\u81ea\u5df1\u5b9e\u73b0\u7684\u63a5\u53e3\uff0c\u8fd9\u6837\u6211\u4eec\u5c31\u80fd\u7f16\u5199\u81ea\u5df1\u7684\u8bed\u6cd5\u89c4\u5219\u4e86\u3002<\/p>\n
    \u4ee5\u8fd9\u91cc\u7684\u65b0\u589e\u7684\u53d6\u6a21\u8fd0\u7b97\u4e3a\u4f8b\uff1a<\/p>\n
    func (v *GScriptVisitor) VisitModExpr(ctx *parser.ModExprContext) interface{} {\n    lhs := v.Visit(ctx.GetLhs())\n    rhs := v.Visit(ctx.GetRhs())\n    return lhs.(int) % rhs.(int)\n}<\/code><\/pre>\n
    \u5f53 Antlr<\/code> \u56de\u8c03 VisitModExpr<\/code> \u65b9\u6cd5\u65f6\uff0c\u4fbf\u80fd\u83b7\u53d6\u5230 % \u7b26\u53f7\u5de6\u53f3\u4e24\u4fa7\u7684\u6570\u636e\uff0c\u8fd9\u65f6\u53ea\u9700\u8981\u505a\u76f8\u5173\u8fd0\u7b97\u5373\u53ef\u3002<\/p>\n
    \u57fa\u4e8e\u8fd9\u4e2a\u6a21\u5f0f\u8fd9\u6b21\u65b0\u589e\u4e86\u4e00\u4e2a statement<\/code>\uff0c\u5177\u4f53\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n
    func TestGScriptVisitor_VisitIfElse8(t *testing.T) {\n    expression := `\nif(3!=(1+2)){\n    return 1+3\n} else {\n    return false\n}`\n    input := antlr.NewInputStream(expression)\n    lexer := parser.NewGScriptLexer(input)\n    stream := antlr.NewCommonTokenStream(lexer, 0)\n    parser := parser.NewGScriptParser(stream)\n    parser.BuildParseTrees = true\n    tree := parser.Prog()\n    visitor := GScriptVisitor{}\n    var result = visitor.Visit(tree)\n    fmt.Println(expression, " result:", result)\n    assert.Equal(t, result, false)\n}<\/code><\/pre>\n
    Antlr \u8fd8\u6709\u5176\u4ed6\u5404\u79cd\u4f18\u52bf\uff0c\u6bd4\u5982\u53ef\u4ee5\u89e3\u51b3\uff1a<\/p>\n