antlr4 python: 监听器在解析时不显示所有内容 json

Question

我正在使用给定的 g4 json 语法 here:

grammar JSON;

json
   : value
   ;

obj
   : '{' pair (',' pair)* '}'
   | '{' '}'
   ;

pair
   : STRING ':' value
   ;

array
   : '[' value (',' value)* ']'
   | '[' ']'
   ;

value
   : STRING
   | NUMBER
   | obj
   | array
   | 'true'
   | 'false'
   | 'null'
   ;


STRING
   : '"' (ESC | SAFECODEPOINT)* '"'
   ;


fragment ESC
   : '\' (["\/bfnrt] | UNICODE)
   ;
fragment UNICODE
   : 'u' HEX HEX HEX HEX
   ;
fragment HEX
   : [0-9a-fA-F]
   ;
fragment SAFECODEPOINT
   : ~ ["\\u0000-\u001F]
   ;


NUMBER
   : '-'? INT ('.' [0-9] +)? EXP?
   ;


fragment INT
   : '0' | [1-9] [0-9]*
   ;

// no leading zeros

fragment EXP
   : [Ee] [+\-]? INT
   ;

// \- since - means "range" inside [...]

WS
   : [ \t\n\r] + -> skip
;

下面是维基百科的 json 示例，我想使用上面的语法对其进行解析：

to_parse = r'''
{
  "firstName": "John",
  "lastName": "Smith",
  "isAlive": true,
  "age": 27,
  "address": {
    "streetAddress": "21 2nd Street",
    "city": "New York",
    "state": "NY",
    "postalCode": "10021-3100"
  },
  "phoneNumbers": [
    {
      "type": "home",
      "number": "212 555-1234"
    },
    {
      "type": "office",
      "number": "646 555-4567"
    },
    {
      "type": "mobile",
      "number": "123 456-7890"
    }
  ],
  "children": [],
  "spouse": null
}
'''

我正在使用 antlr4 python 运行时（在生成词法分析器[lexer_class]、解析器[parser_class] 和侦听器[listener_class] 之后）：

class MyListener(listener_class):

    def enterJson(self, ctx):
        print(inspect.stack()[0][3])

    def exitJson(self, ctx):
        print(inspect.stack()[0][3])

    def enterObj(self, ctx):
        print(inspect.stack()[0][3])

    def exitObj(self, ctx):
        print(inspect.stack()[0][3])

    def enterPair(self, ctx):
        print(inspect.stack()[0][3])

    def exitPair(self, ctx):
        print(inspect.stack()[0][3])

    def enterArray(self, ctx):
        print(inspect.stack()[0][3])

    def exitArray(self, ctx):
        print(inspect.stack()[0][3])

    def enterValue(self, ctx):
        print(inspect.stack()[0][3])

    def exitValue(self, ctx):
        print(inspect.stack()[0][3])


input_stream = InputStream(to_parse)
lexer = lexer_class(input_stream)
token_stream = CommonTokenStream(lexer)
parser = parser_class(token_stream)
# Entry point in the json g4 grammar: json
tree = parser.json()
my_listener = MyListener()
walker = ParseTreeWalker()
walker.walk(my_listener, tree)

仅输出：

enterJson
enterValue
exitValue
exitJson

我的代码没有显示任何数组obj是正常的吗？

[编辑]

我正在使用以下命令生成 *.py 文件（词法分析器、解析器和侦听器）：

java -cp antlr-4.7.2-complete.jar org.antlr.v4.Tool -o ./generation -Dlanguage=Python3 JSON.g4

Answer 1

我无法重现。当我根据您发布的语法生成类，然后运行以下脚本时：

from antlr4 import *
from JSONLexer import JSONLexer as lexer_class
from JSONParser import JSONParser as parser_class
from JSONListener import JSONListener as listener_class


class MyListener(listener_class):

    def enterJson(self, ctx):
        print("enterJson")

    def exitJson(self, ctx):
        print("exitJson")

    def enterObj(self, ctx):
        print("enterObj")

    def exitObj(self, ctx):
        print("exitObj")

    def enterPair(self, ctx):
        print("enterPair")

    def exitPair(self, ctx):
        print("exitPair")

    def enterArray(self, ctx):
        print("enterArray")

    def exitArray(self, ctx):
        print("exitArray")

    def enterValue(self, ctx):
        print("enterValue")

    def exitValue(self, ctx):
        print("exitValue")


to_parse = r'''
{
  "firstName": "John",
  "lastName": "Smith",
  "isAlive": true,
  "age": 27,
  "address": {
    "streetAddress": "21 2nd Street",
    "city": "New York",
    "state": "NY",
    "postalCode": "10021-3100"
  },
  "phoneNumbers": [
    {
      "type": "home",
      "number": "212 555-1234"
    },
    {
      "type": "office",
      "number": "646 555-4567"
    },
    {
      "type": "mobile",
      "number": "123 456-7890"
    }
  ],
  "children": [],
  "spouse": null
}
'''

input_stream = InputStream(to_parse)
lexer = lexer_class(input_stream)
token_stream = CommonTokenStream(lexer)
parser = parser_class(token_stream)
tree = parser.json()
my_listener = MyListener()
walker = ParseTreeWalker()
walker.walk(my_listener, tree)

以下内容打印到我的控制台：

enterJson
enterValue
enterObj
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
enterObj
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
exitObj
exitValue
exitPair
enterPair
enterValue
enterArray
enterValue
enterObj
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
exitObj
exitValue
enterValue
enterObj
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
exitObj
exitValue
enterValue
enterObj
enterPair
enterValue
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
exitObj
exitValue
exitArray
exitValue
exitPair
enterPair
enterValue
enterArray
exitArray
exitValue
exitPair
enterPair
enterValue
exitValue
exitPair
exitObj
exitValue
exitJson

antlr4 python: 监听器在解析时不显示所有内容 json

antlr4 python: listener does not show everything when parsing json

python

json

antlr

antlr4