LALR语法分析表生成算法以及归约分析算法源代码_lr1和lara1的分析能力资源-CSDN文库

共28个文件

h：11个

cpp：10个

txt：2个

编译原理

语法分析

移进归约

LALR

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在编译原理中，LALR（Left-to-right, Leftmost derivation, Rightmost reduction）语法分析是一种广泛应用的技术，用于将源代码转换为中间形式，如抽象语法树（AST）。LALR分析器通过一个称为“解析表”的数据结构来工作，这个表定义了在解析过程中如何处理输入符号流。本文将深入探讨LALR语法分析表的生成算法以及归约分析算法，并结合使用STL库来实现这一过程。我们要理解LALR分析的核心概念。LALR分析器是LR(0)分析器的一种改进，它在构造分析表时考虑了项目集的闭包，并加入了冲突处理机制，使得分析器能够处理更复杂的文法。LR(0)分析器基于状态转移，每个状态对应一组项目集，而每个项目集包含一个输入符号和一个可归约的部分。LALR分析的关键在于如何构建这些状态并解决潜在的移进-归约冲突和归约-归约冲突。 LALR语法分析表的生成通常包括以下几个步骤： 1. **构造初始项目集**：从起始非终结符出发，生成包含起始符号的项目集，例如：`S' -> .S`，其中`S'`是起始符号，`S`是文法的开始符号。 2. **计算闭包**：对每个项目集中的每个项目，检查其右侧是否还有未处理的非终结符。如果是，则将与这些非终结符相关的所有项目添加到当前项目集中。这个过程可能需要迭代多次，直到闭包不再改变。 3. **添加移进项**：对于每个项目集，检查其结束点是否是输入符号。如果是，就添加一个“移进”项，将该输入符号转移到新的项目集。 4. **合并项目集**：如果两个项目集的闭包相同且移进项也相同，那么它们可以合并为一个项目集，以减少分析表的大小。 5. **处理冲突**：在生成过程中，可能会出现移进-归约冲突或归约-归约冲突。LALR分析器尝试解决这些冲突，通常通过优先级和关联性规则来决定处理方式。 6. **生成解析表**：根据项目集和它们的移进、归约操作，生成解析表。这个表包含了每个状态下对于不同输入符号的行动，即“移进”或“归约”。在实现LALR分析算法时，STL库可以提供很大的帮助。例如，可以使用`std::set`或`std::unordered_set`来存储项目集，用`std::map`或`std::unordered_map`来建立状态间的转移关系，以及使用`std::vector`来表示解析表。STL容器的高效性和简洁性使得代码更易于理解和维护。归约分析算法是LALR分析中的另一重要部分。当遇到归约操作时，分析器会根据当前栈顶的若干个符号（对应于归约规则的左侧）和规则右边的符号序列进行操作。这个过程通常涉及以下步骤： 1. **识别归约条件**：如果当前输入符号栈的顶部符号对应于某个规则的左侧，且没有待处理的输入符号，那么可以触发归约。 2. **应用归约规则**：将栈顶的符号替换为规则右边的非终结符，同时更新当前状态，进入下一个分析阶段。 3. **处理归约冲突**：如果在归约时与移进操作冲突，需要根据文法规则和上下文来决定优先处理哪个操作。 4. **调整栈顶指针**：归约后，栈顶指针会向栈底移动，以反映归约后的新状态。归约分析是LALR解析过程中的核心部分，它与解析表中的归约操作对应，确保了分析器能正确地按照文法规则进行解析。 LALR语法分析表的生成和归约分析算法是编译器设计的关键组成部分。通过理解这些概念并使用STL库实现，我们可以构建出高效且健壮的编译器前端，为后续的语义分析和代码生成奠定基础。对于学习编译原理的学生来说，掌握这些技术是迈进编译技术领域的必要步骤。

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LALRGen.rar （28个子文件）

LALRGen

main.cpp 10KB

LALRGen.dsw 537B

LALRGen.dsp 6KB

Debug

out.txt 302KB

input.txt 73B

LALRGen.exe 768KB

run.bat 32B

LALRGen.pdb 1.46MB

lalr

rule.cpp 173B

ruleSet.cpp 178B

table.h 2KB

grammar.h 2KB

lalr.h 550B

itemSet.cpp 173B

element.h 3KB

config.h 4KB

item.cpp 190B

rule.h 4KB

generator.h 36KB

itemSet.h 11KB

ruleSet.h 4KB

elementSet.cpp 207B

item.h 2KB

generator.cpp 28B

elementSet.h 6KB

table.cpp 173B

element.cpp 302B

grammar.cpp 171B

terminators: 0: $ 1: "=" 2: "[" 3: "]" 4: "(" 5: ")" 6: "+" 7: "-" 8: "*" 9: "/" 10: "%" 11: "\" 12: "^" 13: NUM 14: ID 15: "," non-terminators: 0: program 1: expression 2: assign_expresion 3: var_expression 4: unary_expression 5: function_call_expression 6: parament_list 7: add_expression 8: mul_expression 9: power_expression 10: S' rules: 0: program -> expression (rule:0) 1: expression -> assign_expresion (rule:1) 2: assign_expresion -> var_expression "=" assign_expresion (rule:2) 3: unary_expression -> var_expression (rule:3) 4: var_expression -> var_expression "[" expression "]" (rule:4) 5: function_call_expression -> var_expression "(" parament_list ")" (rule:5) 6: assign_expresion -> add_expression (rule:6) 7: add_expression -> add_expression "+" mul_expression (rule:7) 8: add_expression -> add_expression "-" mul_expression (rule:8) 9: add_expression -> mul_expression (rule:9) 10: mul_expression -> mul_expression "*" power_expression (rule:10) 11: mul_expression -> mul_expression "/" power_expression (rule:11) 12: mul_expression -> mul_expression "%" power_expression (rule:12) 13: mul_expression -> mul_expression "\" power_expression (rule:13) 14: mul_expression -> power_expression (rule:14) 15: power_expression -> unary_expression "^" power_expression (rule:15) 16: power_expression -> unary_expression (rule:16) 17: unary_expression -> "(" expression ")" (rule:17) 18: unary_expression -> "+" unary_expression (rule:18) 19: unary_expression -> "-" unary_expression (rule:19) 20: unary_expression -> NUM (rule:20) 21: unary_expression -> function_call_expression (rule:21) 22: var_expression -> ID (rule:22) 23: parament_list -> <empty> (rule:23) 24: parament_list -> expression (rule:24) 25: parament_list -> parament_list "," expression (rule:25) 26: S' -> program (rule:26) state 0: program -> . expression , $ (rule:0) expression -> . assign_expresion , $ (rule:1) assign_expresion -> . var_expression "=" assign_expresion , $ (rule:2) assign_expresion -> . add_expression , $ (rule:6) add_expression -> . add_expression "+" mul_expression , $ (rule:7) add_expression -> . add_expression "+" mul_expression , "+" (rule:7) add_expression -> . add_expression "+" mul_expression , "-" (rule:7) add_expression -> . add_expression "-" mul_expression , $ (rule:8) add_expression -> . add_expression "-" mul_expression , "+" (rule:8) add_expression -> . add_expression "-" mul_expression , "-" (rule:8) add_expression -> . mul_expression , $ (rule:9) add_expression -> . mul_expression , "+" (rule:9) add_expression -> . mul_expression , "-" (rule:9) mul_expression -> . mul_expression "*" power_expression , $ (rule:10) mul_expression -> . mul_expression "*" power_expression , "+" (rule:10) mul_expression -> . mul_expression "*" power_expression , "-" (rule:10) mul_expression -> . mul_expression "*" power_expression , "*" (rule:10) mul_expression -> . mul_expression "*" power_expression , "/" (rule:10) mul_expression -> . mul_expression "*" power_expression , "%" (rule:10) mul_expression -> . mul_expression "*" power_expression , "\" (rule:10) mul_expression -> . mul_expression "/" power_expression , $ (rule:11) mul_expression -> . mul_expression "/" power_expression , "+" (rule:11) mul_expression -> . mul_expression "/" power_expression , "-" (rule:11) mul_expression -> . mul_expression "/" power_expression , "*" (rule:11) mul_expression -> . mul_expression "/" power_expression , "/" (rule:11) mul_expression -> . mul_expression "/" power_expression , "%" (rule:11) mul_expression -> . mul_expression "/" power_expression , "\" (rule:11) mul_expression -> . mul_expression "%" power_expression , $ (rule:12) mul_expression -> . mul_expression "%" power_expression , "+" (rule:12) mul_expression -> . mul_expression "%" power_expression , "-" (rule:12) mul_expression -> . mul_expression "%" power_expression , "*" (rule:12) mul_expression -> . mul_expression "%" power_expression , "/" (rule:12) mul_expression -> . mul_expression "%" power_expression , "%" (rule:12) mul_expression -> . mul_expression "%" power_expression , "\" (rule:12) mul_expression -> . mul_expression "\" power_expression , $ (rule:13) mul_expression -> . mul_expression "\" power_expression , "+" (rule:13) mul_expression -> . mul_expression "\" power_expression , "-" (rule:13) mul_expression -> . mul_expression "\" power_expression , "*" (rule:13) mul_expression -> . mul_expression "\" power_expression , "/" (rule:13) mul_expression -> . mul_expression "\" power_expression , "%" (rule:13) mul_expression -> . mul_expression "\" power_expression , "\" (rule:13) mul_expression -> . power_expression , $ (rule:14) mul_expression -> . power_expression , "+" (rule:14) mul_expression -> . power_expression , "-" (rule:14) mul_expression -> . power_expression , "*" (rule:14) mul_expression -> . power_expression , "/" (rule:14) mul_expression -> . power_expression , "%" (rule:14) mul_expression -> . power_expression , "\" (rule:14) power_expression -> . unary_expression "^" power_expression , $ (rule:15) power_expression -> . unary_expression "^" power_expression , "+" (rule:15) power_expression -> . unary_expression "^" power_expression , "-" (rule:15) power_expression -> . unary_expression "^" power_expression , "*" (rule:15) power_expression -> . unary_expression "^" power_expression , "/" (rule:15) power_expression -> . unary_expression "^" power_expression , "%" (rule:15) power_expression -> . unary_expression "^" power_expression , "\" (rule:15) power_expression -> . unary_expression , $ (rule:16) power_expression -> . unary_expression , "+" (rule:16) power_expression -> . unary_expression , "-" (rule:16) power_expression -> . unary_expression , "*" (rule:16) power_expression -> . unary_expression , "/" (rule:16) power_expression -> . unary_expression , "%" (rule:16) power_expression -> . unary_expression , "\" (rule:16) unary_expression -> . "(" expression ")" , $ (rule:17) unary_expression -> . "(" expression ")" , "+" (rule:17) unary_expression -> . "(" expression ")" , "-" (rule:17) unary_expression -> . "(" expression ")" , "*" (rule:17) unary_expression -> . "(" expression ")" , "/" (rule:17) unary_expression -> . "(" expression ")" , "%" (rule:17) unary_expression -> . "(" expression ")" , "\" (rule:17) unary_expression -> . "(" expression ")" , "^" (rule:17) unary_expression -> . "+" unary_expression , $ (rule:18) unary_expression -> . "+" unary_expression , "+" (rule:18) unary_expression -> . "+" unary_expression , "-" (rule:18) unary_expression -> . "+" unary_expression , "*" (rule:18) unary_expression -> . "+" unary_expression , "/" (rule:18) unary_expression -> . "+" unary_expression , "%" (rule:18) unary_expression -> . "+" unary_expression , "\" (rule:18) unary_expression -> . "+" unary_expression , "^" (rule:18) unary_expression -> . "-" unary_expression , $ (rule:19) unary_expression -> . "-" unary_expression , "+" (rule:19) unary_expression -> . "-" unary_expression , "-" (rule:19) unary_expression -> . "-" unary_expression , "*" (rule:19) unary_expression -> . "-" unary_expression , "/" (rule:19) unary_expression -> . "-" unary_expression , "%" (rule:19) unary_expression -> . "-" unary_expression , "\" (rule:19) unary_expression -> . "-" unary_expression , "^" (rule:19) unary_expression -> . NUM , $ (rule:20) unary_expression -> . NUM , "+" (rule:20) unary_expression -> . NUM , "-" (rule:20) unary_expression -> . NUM , "*" (rule:20) unary_expression -> . NUM , "/" (rule:20) unary_expression -> . NUM , "%" (rule:20) unary_expression -> . NUM , "\" (rule:20) unary_expression -> . NUM , "^" (rule:20) unary_expression -> . var_expression , $ (rule:3) un

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