Java 面向对象编程语言的AST(抽象语法树)是什么样子的?
我正在阅读AST(抽象语法树),但我看到的所有示例都使用以下表达式:Java 面向对象编程语言的AST(抽象语法树)是什么样子的?,java,compiler-construction,programming-languages,abstract-syntax-tree,Java,Compiler Construction,Programming Languages,Abstract Syntax Tree,我正在阅读AST(抽象语法树),但我看到的所有示例都使用以下表达式: a + b * c 可以用类似lispy的语法表示为: (+ a (* b c) ) 这相当于: + / \ a * / \ b c 我的问题是OOPL中类的AST是什么样子的 我的天真尝试是针对以下Java代码: class Person { String name; int age; public String toString() {
a + b * c
可以用类似lispy的语法表示为:
(+ a (* b c) )
这相当于:
+
/ \
a *
/ \
b c
我的问题是OOPL中类的AST是什么样子的
我的天真尝试是针对以下Java代码:
class Person {
String name;
int age;
public String toString() {
return "name";
}
}
是:
但我不太确定我离真正的AST表示有多近或有多远
这取决于我选择的语言吗。需要多少细节?这些“xyzDeclaraction”是需要的还是可以是:
(Person (String name) (int age))
在哪里可以看到实际编程语言的“真实”表示,以了解更多信息 AST是CST(,或,解析树)的抽象。具体语法树是由用于解析文件的结果(语法中)生成的树。所以AST基本上是从语法定义中派生出来的,但是已经转换为for
Exp
/ | \
/ | \ *
Ident BinOp Ident into / \
/ | \ "x" "y"
/ | \
"x" * "y"
总而言之,我认为你文章中的例子看起来不错。我可能会将变量声明包装在varDeclList
中,将函数声明包装在methDeclList
中,将返回语句包装在stmtList
中。(见下文。)
苹果在他的书《Java中的现代编译器实现》中描述了AST的一种或多或少的“真实”表示。(可以找到资源。)
使用这些类,您的程序将表示为:
Program
ClassDeclList
ClassDecl
Identifier
id: Person
VarDeclList
VarDecl
type: String
id: name
VarDecl
type: int
id: age
MethDeclList
MethodDecl
modifiers: public
returnType: String
id: toString
Formals
(empty)
StmtList
returnStmt
Identifier
id: name
请看一下实现
作为第一篇介绍,您也可以阅读这篇文章。OP:我在哪里可以看到实际编程语言的真实表示,以了解更多信息
对于作为Person.java文件的源文本:
class Person {
String name;
int age;
public String toString()
{ return "name"; }
}
下面是使用Java1.6解析器从我们的解析器树的S表达式样式转储中的具体和抽象语法树。所有明显的复杂性几乎都是由语言的真正复杂性(例如Java本身)造成的
CST显然比AST(54个节点)包含更多的内容(139个节点)。给定AST,AST会删除所有可以从语法自动推断的内容。这包括删除不带值的叶子、一元结果,以及将由左或右递归语法规则引起的脊椎压缩到显式列表节点中
左括号表示一个新子树。左括号后面是节点类型的名称@除非您了解DMS可以同时处理多种语言,包括嵌套在彼此内部的语言,否则Java~Java1_2;.6似乎是不必要的。#nnnnnn是节点的内存地址^M表示“此节点有M个父节点,当M==1时关闭。在[…]中的内容是节点值。A{M}表示此列表节点有M个列表子节点。每个节点都印有位置信息
这是具体的语法树(请参阅下面的AST):
这是AST(由DMS从CST自动生成):
2015年3月编辑:
2015年5月编辑:DMS长期以来也在使用Java 1.7和1.8。例如,我想知道
varDecl
和methodDecl
节点是否可以省略,因为我们已经在varDeclList
分支中。最后一个字段的初始化将如何表示?这是一个新节点assignVal
或者值varDecl
?Hm.。在我看来,vardeclist
等是需要的,但在退化情况下,恰好只有一个varDecl
。即ClassDecl
将(除其他外)包含一个VarDeclList
。这就是我在示例树中包含它的原因。您使用哪个DMS产品生成Java AST?我正在尝试下载它,我看到产品测试(代码)覆盖率、源代码浏览器、格式化程序/模糊处理程序等,但没有通用的“解析器”。“@thatWiseGuy几乎所有与Java相关的SD产品都将通过包含用于Java的DMS解析器来构建AST。那些产品不会给你那个AST;他们专注于他们设计的任务(例如,收集测试覆盖率、格式/模糊等)。将AST作为可操作的数据结构和/或XML输出的一个产品是DMS软件再工程工具包(“DMS”)www.semanticdesigns.com/Products/DMS/DMS Toolkit.html及其Java前端。DMS没有试用版下载,请联系SD获取更多详细信息教程链接已断开,请修复
class Person {
String name;
int age;
public String toString()
{ return "name"; }
}
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(type_declarations@Java~Java1_6=15#4885cc0 Line 1 Column 1 File C:/temp/Person.java
(type_declarations@Java~Java1_6=16#4884d80 Line 1 Column 1 File C:/temp/Person.java)type_declarations
(type_declaration@Java~Java1_6=17#4885ca0 Line 1 Column 1 File C:/temp/Person.java
(type_class_modifiers@Java~Java1_6=77#4884dc0 Line 1 Column 1 File C:/temp/Person.java)type_class_modifiers
(class_header@Java~Java1_6=89#4884ec0 Line 1 Column 1 File C:/temp/Person.java
|('class'@Java~Java1_6=459#4884c60[Keyword:0] Line 1 Column 1 File C:/temp/Person.java)'class'
|(IDENTIFIER@Java~Java1_6=447#4884e20[`Person'] Line 1 Column 7 File C:/temp/Person.java)IDENTIFIER
|(type_parameters@Java~Java1_6=408#4884e80 Line 1 Column 14 File C:/temp/Person.java)type_parameters
)class_header
(class_body@Java~Java1_6=94#4885c80 Line 1 Column 14 File C:/temp/Person.java
|('{'@Java~Java1_6=448#4884e60[Keyword:0] Line 1 Column 14 File C:/temp/Person.java)'{'
|(class_body_declarations@Java~Java1_6=111#4885c60 Line 2 Column 5 File C:/temp/Person.java
| (class_body_declarations@Java~Java1_6=111#4885380 Line 2 Column 5 File C:/temp/Person.java
| (class_body_declarations@Java~Java1_6=110#4885400 Line 2 Column 5 File C:/temp/Person.java
| (class_body_declaration@Java~Java1_6=118#4885360 Line 2 Column 5 File C:/temp/Person.java
| |(field_declaration@Java~Java1_6=168#4885440 Line 2 Column 5 File C:/temp/Person.java
| | (field_modifiers@Java~Java1_6=170#4884f40 Line 2 Column 5 File C:/temp/Person.java)field_modifiers
| | (type@Java~Java1_6=191#48852c0 Line 2 Column 5 File C:/temp/Person.java
| | (name@Java~Java1_6=406#48851e0 Line 2 Column 5 File C:/temp/Person.java
| | (IDENTIFIER@Java~Java1_6=447#4884f20[`String'] Line 2 Column 5 File C:/temp/Person.java)IDENTIFIER
| | (type_arguments@Java~Java1_6=407#4885160 Line 2 Column 12 File C:/temp/Person.java)type_arguments
| | )name
| | (brackets@Java~Java1_6=157#4885260 Line 2 Column 12 File C:/temp/Person.java)brackets
| | )type
| | (variable_declarator_list@Java~Java1_6=179#4884e00 Line 2 Column 12 File C:/temp/Person.java
| | (variable_declarator@Java~Java1_6=181#4885300 Line 2 Column 12 File C:/temp/Person.java
| | (variable_declarator_id@Java~Java1_6=167#4885320 Line 2 Column 12 File C:/temp/Person.java
| | |(IDENTIFIER@Java~Java1_6=447#4885140[`name'] Line 2 Column 12 File C:/temp/Person.java)IDENTIFIER
| | |(brackets@Java~Java1_6=157#4885040 Line 2 Column 16 File C:/temp/Person.java)brackets
| | )variable_declarator_id
| | )variable_declarator
| | )variable_declarator_list
| | (';'@Java~Java1_6=440#4885100[Keyword:0] Line 2 Column 16 File C:/temp/Person.java)';'
| |)field_declaration
| )class_body_declaration
| )class_body_declarations
| (class_body_declaration@Java~Java1_6=118#48852e0 Line 3 Column 5 File C:/temp/Person.java
| (field_declaration@Java~Java1_6=168#4885480 Line 3 Column 5 File C:/temp/Person.java
| |(field_modifiers@Java~Java1_6=170#4885340 Line 3 Column 5 File C:/temp/Person.java)field_modifiers
| |(type@Java~Java1_6=192#4885220 Line 3 Column 5 File C:/temp/Person.java
| | (primitive_type@Java~Java1_6=198#4885420 Line 3 Column 5 File C:/temp/Person.java
| | ('int'@Java~Java1_6=479#48853e0[Keyword:0] Line 3 Column 5 File C:/temp/Person.java)'int'
| | )primitive_type
| | (brackets@Java~Java1_6=157#4885200 Line 3 Column 12 File C:/temp/Person.java)brackets
| |)type
| |(variable_declarator_list@Java~Java1_6=179#4885540 Line 3 Column 12 File C:/temp/Person.java
| | (variable_declarator@Java~Java1_6=181#4885520 Line 3 Column 12 File C:/temp/Person.java
| | (variable_declarator_id@Java~Java1_6=167#4885500 Line 3 Column 12 File C:/temp/Person.java
| | (IDENTIFIER@Java~Java1_6=447#4884fc0[`age'] Line 3 Column 12 File C:/temp/Person.java)IDENTIFIER
| | (brackets@Java~Java1_6=157#48854e0 Line 3 Column 15 File C:/temp/Person.java)brackets
| | )variable_declarator_id
| | )variable_declarator
| |)variable_declarator_list
| |(';'@Java~Java1_6=440#48854c0[Keyword:0] Line 3 Column 15 File C:/temp/Person.java)';'
| )field_declaration
| )class_body_declaration
| )class_body_declarations
| (class_body_declaration@Java~Java1_6=117#4885c40 Line 4 Column 5 File C:/temp/Person.java
| (method_declaration@Java~Java1_6=135#4885c00 Line 4 Column 5 File C:/temp/Person.java
| (method_modifiers@Java~Java1_6=141#4885700 Line 4 Column 5 File C:/temp/Person.java
| |(method_modifiers@Java~Java1_6=142#4884e40 Line 4 Column 5 File C:/temp/Person.java)method_modifiers
| |(method_modifier@Java~Java1_6=147#48856a0 Line 4 Column 5 File C:/temp/Person.java
| | ('public'@Java~Java1_6=453#48853a0[Keyword:0] Line 4 Column 5 File C:/temp/Person.java)'public'
| |)method_modifier
| )method_modifiers
| (type_parameters@Java~Java1_6=408#4885740 Line 4 Column 12 File C:/temp/Person.java)type_parameters
| (type@Java~Java1_6=191#4885900 Line 4 Column 12 File C:/temp/Person.java
| |(name@Java~Java1_6=406#48852a0 Line 4 Column 12 File C:/temp/Person.java
| | (IDENTIFIER@Java~Java1_6=447#4885660[`String'] Line 4 Column 12 File C:/temp/Person.java)IDENTIFIER
| | (type_arguments@Java~Java1_6=407#48851a0 Line 4 Column 19 File C:/temp/Person.java)type_arguments
| |)name
| |(brackets@Java~Java1_6=157#48858c0 Line 4 Column 19 File C:/temp/Person.java)brackets
| )type
| (IDENTIFIER@Java~Java1_6=447#48855c0[`toString'] Line 4 Column 19 File C:/temp/Person.java)IDENTIFIER
| (parameters@Java~Java1_6=158#48858e0 Line 4 Column 27 File C:/temp/Person.java
| |('('@Java~Java1_6=450#4885840[Keyword:0] Line 4 Column 27 File C:/temp/Person.java)'('
| |(')'@Java~Java1_6=451#4885620[Keyword:0] Line 4 Column 28 File C:/temp/Person.java)')'
| )parameters
| (brackets@Java~Java1_6=157#4885060 Line 5 Column 7 File C:/temp/Person.java)brackets
| (block@Java~Java1_6=217#4885be0 Line 5 Column 7 File C:/temp/Person.java
| |('{'@Java~Java1_6=448#48851c0[Keyword:0] Line 5 Column 7 File C:/temp/Person.java)'{'
| |(statement_sequence@Java~Java1_6=218#4885ba0 Line 5 Column 9 File C:/temp/Person.java
| | (statement_sequence_member@Java~Java1_6=223#4885b80 Line 5 Column 9 File C:/temp/Person.java
| | (executable_statement@Java~Java1_6=243#4885b60 Line 5 Column 9 File C:/temp/Person.java
| | ('return'@Java~Java1_6=491#4884f60[Keyword:0] Line 5 Column 9 File C:/temp/Person.java)'return'
| | (expression@Java~Java1_6=332#4885ac0 Line 5 Column 16 File C:/temp/Person.java
| | |(conditional_expression@Java~Java1_6=345#4885a60 Line 5 Column 16 File C:/temp/Person.java
| | | (conditional_or_expression@Java~Java1_6=347#4885a20 Line 5 Column 16 File C:/temp/Person.java
| | | (conditional_and_expression@Java~Java1_6=349#48859e0 Line 5 Column 16 File C:/temp/Person.java
| | | (inclusive_or_expression@Java~Java1_6=351#48857e0 Line 5 Column 16 File C:/temp/Person.java
| | | |(exclusive_or_expression@Java~Java1_6=353#48855a0 Line 5 Column 16 File C:/temp/Person.java
| | | | (and_expression@Java~Java1_6=355#4885940 Line 5 Column 16 File C:/temp/Person.java
| | | | (equality_expression@Java~Java1_6=357#4885880 Line 5 Column 16 File C:/temp/Person.java
| | | | (relational_expression@Java~Java1_6=360#4885800 Line 5 Column 16 File C:/temp/Person.java
| | | | |(shift_expression@Java~Java1_6=366#48856c0 Line 5 Column 16 File C:/temp/Person.java
| | | | | (additive_expression@Java~Java1_6=370#4885180 Line 5 Column 16 File C:/temp/Person.java
| | | | | (multiplicative_expression@Java~Java1_6=373#4885780 Line 5 Column 16 File C:/temp/Person.java
| | | | | (unary_expression@Java~Java1_6=383#4885600 Line 5 Column 16 File C:/temp/Person.java
| | | | | |(unary_expression_not_plus_minus@Java~Java1_6=389#4885680 Line 5 Column 16 File C:/temp/Person.java
| | | | | | (literal@Java~Java1_6=390#4884f80 Line 5 Column 16 File C:/temp/Person.java
| | | | | | (STRING@Java~Java1_6=536#4885120[`name'] Line 5 Column 16 File C:/temp/Person.java)STRING
| | | | | | )literal
| | | | | |)unary_expression_not_plus_minus
| | | | | )unary_expression
| | | | | )multiplicative_expression
| | | | | )additive_expression
| | | | |)shift_expression
| | | | )relational_expression
| | | | )equality_expression
| | | | )and_expression
| | | |)exclusive_or_expression
| | | )inclusive_or_expression
| | | )conditional_and_expression
| | | )conditional_or_expression
| | |)conditional_expression
| | )expression
| | (';'@Java~Java1_6=440#48856e0[Keyword:0] Line 5 Column 22 File C:/temp/Person.java)';'
| | )executable_statement
| | )statement_sequence_member
| |)statement_sequence
| |('}'@Java~Java1_6=449#4885b40[Keyword:0] Line 5 Column 28 File C:/temp/Person.java)'}'
| )block
| )method_declaration
| )class_body_declaration
|)class_body_declarations
|('}'@Java~Java1_6=449#4885bc0[Keyword:0] Line 6 Column 1 File C:/temp/Person.java)'}'
)class_body
)type_declaration
)type_declarations
(optional_CONTROL_Z@Java~Java1_6=5#4885ce0 Line 7 Column 1 File C:/temp/Person.java)optional_CONTROL_Z
)compilation_unit
(compilation_unit@Java~Java1_6=1#486f900^0 Line 1 Column 1 File C:/temp/Person.java
(type_declarations@Java~Java1_6=15#486f4c0 {1} Line 1 Column 1 File C:/temp/Person.java
(type_declaration@Java~Java1_6=17#486f5e0 Line 1 Column 1 File C:/temp/Person.java
(type_class_modifiers@Java~Java1_6=77#486eda0 Line 1 Column 1 File C:/temp/Person.java)type_class_modifiers
(class_header@Java~Java1_6=89#486ee60 Line 1 Column 1 File C:/temp/Person.java
|(IDENTIFIER@Java~Java1_6=447#486ede0[`Person'] Line 1 Column 7 File C:/temp/Person.java)IDENTIFIER
|(type_parameters@Java~Java1_6=408#486ee20 Line 1 Column 14 File C:/temp/Person.java)type_parameters
)class_header
(class_body@Java~Java1_6=94#486f040 Line 1 Column 14 File C:/temp/Person.java
|(class_body_declarations@Java~Java1_6=111#486ee40 {3} Line 2 Column 5 File C:/temp/Person.java
| (class_body_declaration@Java~Java1_6=118#486f300 Line 2 Column 5 File C:/temp/Person.java
| (field_declaration@Java~Java1_6=168#486f380 Line 2 Column 5 File C:/temp/Person.java
| (field_modifiers@Java~Java1_6=170#486eec0 Line 2 Column 5 File C:/temp/Person.java)field_modifiers
| (type@Java~Java1_6=191#486f240 Line 2 Column 5 File C:/temp/Person.java
| |(name@Java~Java1_6=406#486f180 Line 2 Column 5 File C:/temp/Person.java
| | (IDENTIFIER@Java~Java1_6=447#486eea0[`String'] Line 2 Column 5 File C:/temp/Person.java)IDENTIFIER
| | (type_arguments@Java~Java1_6=407#486f0e0 Line 2 Column 12 File C:/temp/Person.java)type_arguments
| |)name
| |(brackets@Java~Java1_6=157#486f200 Line 2 Column 12 File C:/temp/Person.java)brackets
| )type
| (variable_declarator@Java~Java1_6=181#486ef20 Line 2 Column 12 File C:/temp/Person.java
| |(variable_declarator_id@Java~Java1_6=167#486efe0 Line 2 Column 12 File C:/temp/Person.java
| | (IDENTIFIER@Java~Java1_6=447#486f0c0[`name'] Line 2 Column 12 File C:/temp/Person.java)IDENTIFIER
| | (brackets@Java~Java1_6=157#486f060 Line 2 Column 16 File C:/temp/Person.java)brackets
| |)variable_declarator_id
| )variable_declarator
| )field_declaration
| )class_body_declaration
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| (field_declaration@Java~Java1_6=168#486f320 Line 3 Column 5 File C:/temp/Person.java
| (field_modifiers@Java~Java1_6=170#486f2a0 Line 3 Column 5 File C:/temp/Person.java)field_modifiers
| (type@Java~Java1_6=192#486eee0 Line 3 Column 5 File C:/temp/Person.java
| |(primitive_type@Java~Java1_6=198#486ef60 Line 3 Column 5 File C:/temp/Person.java)primitive_type
| |(brackets@Java~Java1_6=157#486ee00 Line 3 Column 12 File C:/temp/Person.java)brackets
| )type
| (variable_declarator@Java~Java1_6=181#486f2c0 Line 3 Column 12 File C:/temp/Person.java
| |(variable_declarator_id@Java~Java1_6=167#486f3a0 Line 3 Column 12 File C:/temp/Person.java
| | (IDENTIFIER@Java~Java1_6=447#486f120[`age'] Line 3 Column 12 File C:/temp/Person.java)IDENTIFIER
| | (brackets@Java~Java1_6=157#486ef00 Line 3 Column 15 File C:/temp/Person.java)brackets
| |)variable_declarator_id
| )variable_declarator
| )field_declaration
| )class_body_declaration
| (class_body_declaration@Java~Java1_6=117#486f7a0 Line 4 Column 5 File C:/temp/Person.java
| (method_declaration@Java~Java1_6=135#486f480 Line 4 Column 5 File C:/temp/Person.java
| (method_modifiers@Java~Java1_6=141#486f460 {1} Line 4 Column 5 File C:/temp/Person.java
| |(method_modifier@Java~Java1_6=147#486f400 Line 4 Column 5 File C:/temp/Person.java)method_modifier
| )method_modifiers
| (type_parameters@Java~Java1_6=408#486f540 Line 4 Column 12 File C:/temp/Person.java)type_parameters
| (type@Java~Java1_6=191#486f740 Line 4 Column 12 File C:/temp/Person.java
| |(name@Java~Java1_6=406#486f620 Line 4 Column 12 File C:/temp/Person.java
| | (IDENTIFIER@Java~Java1_6=447#486f080[`String'] Line 4 Column 12 File C:/temp/Person.java)IDENTIFIER
| | (type_arguments@Java~Java1_6=407#486f640 Line 4 Column 19 File C:/temp/Person.java)type_arguments
| |)name
| |(brackets@Java~Java1_6=157#486f700 Line 4 Column 19 File C:/temp/Person.java)brackets
| )type
| (IDENTIFIER@Java~Java1_6=447#486f140[`toString'] Line 4 Column 19 File C:/temp/Person.java)IDENTIFIER
| (parameters@Java~Java1_6=158#486f760 Line 4 Column 27 File C:/temp/Person.java)parameters
| (brackets@Java~Java1_6=157#486f820 Line 5 Column 7 File C:/temp/Person.java)brackets
| (block@Java~Java1_6=217#486f780 Line 5 Column 7 File C:/temp/Person.java
| |(statement_sequence@Java~Java1_6=218#486f6e0 Line 5 Column 9 File C:/temp/Person.java
| | (statement_sequence_member@Java~Java1_6=223#486f6c0 Line 5 Column 9 File C:/temp/Person.java
| | (executable_statement@Java~Java1_6=243#486f6a0 Line 5 Column 9 File C:/temp/Person.java
| | (unary_expression_not_plus_minus@Java~Java1_6=389#486f720 Line 5 Column 16 File C:/temp/Person.java
| | |(literal@Java~Java1_6=390#486f280 Line 5 Column 16 File C:/temp/Person.java
| | | (STRING@Java~Java1_6=536#486f160[`name'] Line 5 Column 16 File C:/temp/Person.java)STRING
| | |)literal
| | )unary_expression_not_plus_minus
| | )executable_statement
| | )statement_sequence_member
| |)statement_sequence
| )block
| )method_declaration
| )class_body_declaration
|)class_body_declarations
)class_body
)type_declaration
)type_declarations
(optional_CONTROL_Z@Java~Java1_6=5#486f4e0 Line 7 Column 1 File C:/temp/Person.java)optional_CONTROL_Z
)compilation_unit