尽管在文档和论坛中进行了长时间的搜索，我仍然无法在 node.js 中使用 JSON 格式获得 Jison 开始条件 的正确语法

> ** Documentation at http://zaach.github.io/jison/docs/ says:
> // Using the JSON format, start conditions are defined with an array
> // before the rule’s 
> matcher {rules:[
>     [['expect'], '[0-9]+"."[0-9]+', 'console.log( "found a float, = " + yytext );'
>     ]]}

但不幸的是，没有人不提供完整的工作示例。

我试图排除两个标签之间的任何文本。在 lex 中将使用开始条件。 Jison 文档说它应该可以工作。尽管如此，由于 Jison 错误消息不是很直观，我很乐意找到一个工作示例以继续前进。

有人有解决方案吗？

var jison    = require("jison").Parser;

grammar = {  
    "lex": {
        "rules" : [ [" +" , "/* skip whitespace */"]
            ,[['mode1'], '[0-z]+\\b'        , "return 'INFO';"]
            ,[['mode1'], '<\\/extensions>'  , "this.popState(); return 'EXTEND';"]
            ,['<extensions>'                , "this.begin('mode1'); return 'EXTSTART';"]
            ,['$'                           , "return 'EOL';"]
        ]
    },  // end Lex rules

    "bnf": { // WARNING: only one space in between TOKEN ex: "STOP EOF"
        'data': [["EOL"      , "this.cmd='EMPTY'    ; return (this);"]           
           ,['EXTSTART INFO EXTEND EOL'  ,"this.cmd='EXTEN';this.value=$2;return (this);"]
           ]
    }};

  parser    = new jison(grammar);

  test= "\
    <extensions>\
      <opencpn:start></opencpn:start><opencpn:end></opencpn:end>\
      <opencpn:viz>1</opencpn:viz>\
     <opencpn:guid>714d1d6e-78be-46a0-af6e-2f3d0c505f6d</opencpn:guid>\
    </extensions>";

  data=parser.parse (test);

我当前的示例失败了

/node_modules/jison/node_modules/jison-lex/regexp-lexer.js:42 startConditions[conditions[k]].rules.push(i);

最佳答案

不幸的是，没有人回答我的问题:)

我不得不对 Jison Lexer 代码进行逆向工程以找出正确的语法。我想这可能对其他人有帮助，在答案之后:)

Jison 的词法条件在 JSON 语法下工作良好，但它们应该在名为 "startConditions" 的数组中预先声明，如下例所示。

grammar = { 
   "lex": {

       "startConditions" : { "INITIAL":"// Default initial Jison/Lex context"
            ,"MOD_EXT": "// extenstions context "
            ,"MOD_RTE": "// routes context"
        },

        "rules" : [['[\\n\\s]+' , "/* skip whitespace & new lines */"]
            // extensions blocs
            ,[['INITIAL'], '<extensions>'     , "this.begin('MOD_EXT');"]
            ,[['MOD_EXT'], '<\\/extensions>'  , "this.popState();"]
            ,[['MOD_EXT'], '[<>\\/\\-\\s\\n]', "/* ignore */"]
            ,[['MOD_EXT'], '[0-z]+'           , "/* ignore */"]
        Etc...

为了方便大家生活，这里先做一个简单的工作实例。

// Sample JISON start conditions with Jason syntax
var jison    = require("jison").Parser;

grammar = { 

    "lex": {
         "macros": {  // few usefull macro
            "slash": "\\/",
            "space": "\\s+",
            "quot" : "\\\'",
            "dquot": "\\\"",
            "dot"  : "\\.",
            "digit": "[0-9]",
            "int"  : "-?([0-9]+)",
            "float": "-?([0-9]*\\.[0-9]+)",
            "hexa" : "([0-9]|(a-h)|(A-H])+"
        },

       "startConditions" : { "INITIAL":"// Default initial Jison/Lex context"
            ,"MOD_EXT": "// extenstions context "
            ,"MOD_RTE": "// routes context"
        },

        "rules" : [['[\\n\\s]+' , "/* skip whitespace & new lines */"]
            // extensions blocs
            ,[['INITIAL'], '<extensions>'     , "this.begin('MOD_EXT');"]
            ,[['MOD_EXT'], '<\\/extensions>'  , "this.popState();"]
            ,[['MOD_EXT'], '[<>\\/\\-\\s\\n]', "/* ignore */"]
            ,[['MOD_EXT'], '[0-z]+'           , "/* ignore */"]

            // routes points blocs
            ,[['INITIAL'],'<rtept' , "this.begin('MOD_RTE'); return 'RTE_BEG';"]
            ,[['MOD_RTE'], '<\\/rtept>'       , "this.popState(); return 'RTE_END';"]
            ,[['MOD_RTE'], 'lat='             , "return 'LAT';"]
            ,[['MOD_RTE'], 'lon='             , "return 'LON';"]
            ,[['MOD_RTE'], '{float}'          , "return 'CARD';"]
            ,[['MOD_RTE'], '<name>'           , "return 'NAME_BEG';"]
            ,[['MOD_RTE'], '<\\/name>'        , "return 'NAME_END';"]
            ,[['MOD_RTE'], '<time>'           , "return 'TIME_BEG';"]
            ,[['MOD_RTE'], '<\\/time>'        , "return 'TIME_END';"]
            ,[['MOD_RTE'], '<sym>'            , "return 'SYM_BEG';"]
            ,[['MOD_RTE'], '<\\/sym>'         , "return 'SYM_END';"]
            ,[['MOD_RTE'], '<type>'           , "return 'TYPE_BEG';"]
            ,[['MOD_RTE'], '<\\/type>'        , "return 'TYPE_END';"]
            ,[['MOD_RTE'], '<extensions>'     , "this.begin('MOD_EXT');"]
            ,[['MOD_RTE'], '([0-z]|[-+])+\\b' , "return 'TEXT';"]
            ,[['MOD_RTE'], '[>{quot}{dquot}{space}]' , "// ignore"]

            // end of parsing buffer
            ,['$'                            , "return 'EOL';"]
        ]
    },  // end Lex rules

    "bnf": { // WARNING: only one space in between TOKEN ex: "STOP EOF"
        'data': [
            ["EOL"           ,  "return ('EMPTY');"]
           ,["ROUTEPOINTS EOL", "return (this.route);"]
           ]

        // handle multiple waypoints
         // A routepoint should at least have a LAT+LONG+NAME
        ,'ROUTEPOINTS' : [ // store all waypoint in an array
            ["ROUTEPOINT", "console.log('Parsing First Waypts=%j',this.waypts);this.route=[]; this.route.push(this.waypts);"]
           ,["ROUTEPOINTS ROUTEPOINT", "console.log('Parsing Next  Waypts=%j',this.waypts);;this.route.push(this.waypts);"]

        ]

        // A routepoint should at least have a LAT+LONG+NAME
        ,'ROUTEPOINT' :  [ // <rtept lat='47.542780648' lon='-2.896743643'>...
            ["RTE_BEG LATITUDE LONGITUDE DATE NAME SYM TYPE RTE_END", "this.waypts={lat:$2,lon:$3,name:$5,date:$4};"]
           ,["RTE_BEG LATITUDE LONGITUDE DATE NAME RTE_END", "this.waypts={lat:$2,lon:$3,name:$5,date:$4};"]
           ,["RTE_BEG LATITUDE LONGITUDE NAME RTE_END", "this.waypts={lat:$2,lon:$3,name:$4,date:'unknow'};"]
        ]  
        // lat='47.542780648'
        ,'LATITUDE'    : [["LAT CARD", "$$=$2;"]]          
        //  lon='-2.896743643'
        , 'LONGITUDE'  : [["LON CARD", "$$=$2;"]]
        //<time>2014-09-16T21:55:19Z</time>\
        , 'DATE'       : [["TIME_BEG TEXT TIME_END", "$$=$2;"]]
        // <name>001</name>\
        , 'NAME'       : [["NAME_BEG TEXT NAME_END", "$$=$2;"]]
        // <sym>001</name>\
        , 'SYM'        : [["SYM_BEG TEXT SYM_END", "//ignore"]]
        // <name>001</name>\
        , 'TYPE'       : [["TYPE_BEG TEXT TYPE_END", "//ignore"]]

    }};


  parser    = new jison(grammar);

  test= "\
    <extensions>\
        <opencpn:start></opencpn:start><opencpn:end></opencpn:end>\
        <opencpn:viz>1</opencpn:viz>\
        <opencpn:guid>714d1d6e-78be-46a0-af6e-2f3d0c505f6d</opencpn:guid>\
    </extensions>\
    <rtept lat='47.542780648' lon='-2.896743643'>\
        <time>2014-09-16T21:55:19Z</time>\
        <name>001</name>\
        <sym>diamond</sym>\
        <type>WPT</type>\
        <extensions>\
            <opencpn:guid>408c309c-6a8c-411d-815b-0c0054646d45</opencpn:guid>\
            <opencpn:viz>1</opencpn:viz>\
            <opencpn:viz_name>0</opencpn:viz_name>\
            <opencpn:auto_name>1</opencpn:auto_name>\
        </extensions>\
    </rtept>\
    <rtept lat='44.542780648' lon='-4.896743643'>\
        <time>2014-08-16T21:55:19Z</time>\
        <name>002</name>\
    </rtept>\
    <rtept lat='43.542780648' lon='-5.896743643'>\
        <name>003</name>\
    </rtept>\
    <rtept lat='48.542780648' lon='-3.896743643'>\
        <time>2014-10-16T21:55:19Z</time>\
        <name>004</name>\
        <sym>diamond</sym>\
        <type>WPT</type>\
        <extensions>\
            <opencpn:guid>408c309c-6a8c-411d-815b-0c0054646d45</opencpn:guid>\
            <opencpn:viz>1</opencpn:viz>\
            <opencpn:viz_name>0</opencpn:viz_name>\
            <opencpn:auto_name>1</opencpn:auto_name>\
        </extensions>\
    </rtept>";

  route=parser.parse (test);

  console.log ("\n\nMy GPX route's waypoints");
  for (var waypts in route) {
      console.log (" -- name: %s  Lon: %s Lat:%s Date:%s", route [waypts].name, route [waypts].lat, route [waypts].lon, route [waypts].date);
  };

  console.log ("done");

关于javascript - json 格式的 jison 开始条件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25889540/