使用Lex和Yacc开发C语言的编译器

(1) 从网站：http://www.lysator.liu.se/c/  下载C语言的语法文件：
The ANSI C grammar (Yacc and Lex)
(2) 编译词法文件： > lex c.l(3) 编译语法文件：
> yacc -dv c.y说明：-d：产生头文件y.yab.h，-v：产生分析表y.output。针对else产生的移进规约冲突，采用了yacc的默认动作“移进”解决。
(4) 编译语法分析器：
> cc lex.yy.c y.tab.c -ll(5) 测试：
编写测试程序test.c #include "stdio.h"
int main()...{
    int a = 0;
    for(; a < 10; a++)...{
        printf("hello from sun! ");
    }
}运行： > ./a.out < test.c
结果如下：  "stdio.h"
int ()...{
        int  = ;
        for(;  < ; ++)...{
                int("hello from sun hong hao! ");
        }
}

发现c.y文件中没有语义动作。只是进行了词法扫描一下，所以得到结果就是上面的样子了。

(5) 贴一下y.out里的规则：
   0  $accept : translation_unit $end

   1  primary_expression : IDENTIFIER
   2                     | CONSTANT
   3                     | STRING_LITERAL
   4                     | '(' expression ')'

   5  postfix_expression : primary_expression
   6                     | postfix_expression '[' expression ']'
   7                     | postfix_expression '(' ')'
   8                     | postfix_expression '(' argument_expression_list ')'
   9                     | postfix_expression '.' IDENTIFIER
  10                     | postfix_expression PTR_OP IDENTIFIER
  11                     | postfix_expression INC_OP
  12                     | postfix_expression DEC_OP

  13  argument_expression_list : assignment_expression
  14                           | argument_expression_list ',' assignment_expression

  15  unary_expression : postfix_expression
  16                   | INC_OP unary_expression
  17                   | DEC_OP unary_expression
  18                   | unary_operator cast_expression
  19                   | SIZEOF unary_expression
  20                   | SIZEOF '(' type_name ')'

  21  unary_operator : '&'
  22                 | '*'
  23                 | '+'
  24                 | '-'
  25                 | '~'
  26                 | '!'

  27  cast_expression : unary_expression
  28                  | '(' type_name ')' cast_expression

  29  multiplicative_expression : cast_expression
  30                            | multiplicative_expression '*' cast_expression
  31                            | multiplicative_expression '/' cast_expression
  32                            | multiplicative_expression '%' cast_expression

  33  additive_expression : multiplicative_expression
  34                      | additive_expression '+' multiplicative_expression
  35                      | additive_expression '-' multiplicative_expression

  36  shift_expression : additive_expression
  37                   | shift_expression LEFT_OP additive_expression
  38                   | shift_expression RIGHT_OP additive_expression

  39  relational_expression : shift_expression
  40                        | relational_expression '<' shift_expression
  41                        | relational_expression '>' shift_expression
  42                        | relational_expression LE_OP shift_expression
  43                        | relational_expression GE_OP shift_expression

  44  equality_expression : relational_expression
  45                      | equality_expression EQ_OP relational_expression
  46                      | equality_expression NE_OP relational_expression

  47  and_expression : equality_expression
  48                 | and_expression '&' equality_expression

  49  exclusive_or_expression : and_expression
  50                          | exclusive_or_expression '^' and_expression

  51  inclusive_or_expression : exclusive_or_expression
  52                          | inclusive_or_expression '|' exclusive_or_expression

  53  logical_and_expression : inclusive_or_expression
  54                         | logical_and_expression AND_OP inclusive_or_expression

  55  logical_or_expression : logical_and_expression
  56                        | logical_or_expression OR_OP logical_and_expression

  57  conditional_expression : logical_or_expression
  58                         | logical_or_expression '?' expression ':' conditional_expression

  59  assignment_expression : conditional_expression
  60                        | unary_expression assignment_operator assignment_expression

  61  assignment_operator : '='
  62                      | MUL_ASSIGN
  63                      | DIV_ASSIGN
  64                      | MOD_ASSIGN
  65                      | ADD_ASSIGN
  66                      | SUB_ASSIGN
  67                      | LEFT_ASSIGN
  68                      | RIGHT_ASSIGN
  69                      | AND_ASSIGN
  70                      | XOR_ASSIGN
  71                      | OR_ASSIGN

  72  expression : assignment_expression
  73             | expression ',' assignment_expression

  74  constant_expression : conditional_expression

  75  declaration : declaration_specifiers ';'
  76              | declaration_specifiers init_declarator_list ';'

  77  declaration_specifiers : storage_class_specifier
  78                         | storage_class_specifier declaration_specifiers
  79                         | type_specifier
  80                         | type_specifier declaration_specifiers
  81                         | type_qualifier
  82                         | type_qualifier declaration_specifiers

  83  init_declarator_list : init_declarator
  84                       | init_declarator_list ',' init_declarator

  85  init_declarator : declarator
  86                  | declarator '=' initializer

  87  storage_class_specifier : TYPEDEF
  88                          | EXTERN
  89                          | STATIC
  90                          | AUTO
  91                          | REGISTER

  92  type_specifier : VOID
  93                 | CHAR
  94                 | SHORT
  95                 | INT
  96                 | LONG
  97                 | FLOAT
  98                 | DOUBLE
  99                 | SIGNED
 100                 | UNSIGNED
 101                 | struct_or_union_specifier
 102                 | enum_specifier
 103                 | TYPE_NAME

 104  struct_or_union_specifier : struct_or_union IDENTIFIER '{' struct_declaration_list '}'
 105                            | struct_or_union '{' struct_declaration_list '}'
 106                            | struct_or_union IDENTIFIER

 107  struct_or_union : STRUCT
 108                  | UNION

 109  struct_declaration_list : struct_declaration
 110                          | struct_declaration_list struct_declaration

 111  struct_declaration : specifier_qualifier_list struct_declarator_list ';'

 112  specifier_qualifier_list : type_specifier specifier_qualifier_list
 113                           | type_specifier
 114                           | type_qualifier specifier_qualifier_list
 115                           | type_qualifier

 116  struct_declarator_list : struct_declarator
 117                         | struct_declarator_list ',' struct_declarator

 118  struct_declarator : declarator
 119                    | ':' constant_expression
 120                    | declarator ':' constant_expression

 121  enum_specifier : ENUM '{' enumerator_list '}'
 122                 | ENUM IDENTIFIER '{' enumerator_list '}'
 123                 | ENUM IDENTIFIER

 124  enumerator_list : enumerator
 125                  | enumerator_list ',' enumerator

 126  enumerator : IDENTIFIER
 127             | IDENTIFIER '=' constant_expression

 128  type_qualifier : CONST
 129                 | VOLATILE

 130  declarator : pointer direct_declarator
 131             | direct_declarator

 132  direct_declarator : IDENTIFIER
 133                    | '(' declarator ')'
 134                    | direct_declarator '[' constant_expression ']'
 135                    | direct_declarator '[' ']'
 136                    | direct_declarator '(' parameter_type_list ')'
 137                    | direct_declarator '(' identifier_list ')'
 138                    | direct_declarator '(' ')'

 139  pointer : '*'
 140          | '*' type_qualifier_list
 141          | '*' pointer
 142          | '*' type_qualifier_list pointer

 143  type_qualifier_list : type_qualifier
 144                      | type_qualifier_list type_qualifier

 145  parameter_type_list : parameter_list
 146                      | parameter_list ',' ELLIPSIS

 147  parameter_list : parameter_declaration
 148                 | parameter_list ',' parameter_declaration

 149  parameter_declaration : declaration_specifiers declarator
 150                        | declaration_specifiers abstract_declarator
 151                        | declaration_specifiers

 152  identifier_list : IDENTIFIER
 153                  | identifier_list ',' IDENTIFIER

 154  type_name : specifier_qualifier_list
 155            | specifier_qualifier_list abstract_declarator

 156  abstract_declarator : pointer
 157                      | direct_abstract_declarator
 158                      | pointer direct_abstract_declarator

 159  direct_abstract_declarator : '(' abstract_declarator ')'
 160                             | '[' ']'
 161                             | '[' constant_expression ']'
 162                             | direct_abstract_declarator '[' ']'
 163                             | direct_abstract_declarator '[' constant_expression ']'
 164                             | '(' ')'
 165                             | '(' parameter_type_list ')'
 166                             | direct_abstract_declarator '(' ')'
 167                             | direct_abstract_declarator '(' parameter_type_list ')'

 168  initializer : assignment_expression
 169              | '{' initializer_list '}'
 170              | '{' initializer_list ',' '}'

 171  initializer_list : initializer
 172                   | initializer_list ',' initializer

 173  statement : labeled_statement
 174            | compound_statement
 175            | expression_statement
 176            | selection_statement
 177            | iteration_statement
 178            | jump_statement

 179  labeled_statement : IDENTIFIER ':' statement
 180                    | CASE constant_expression ':' statement
 181                    | DEFAULT ':' statement

 182  compound_statement : '{' '}'
 183                     | '{' statement_list '}'
 184                     | '{' declaration_list '}'
 185                     | '{' declaration_list statement_list '}'

 186  declaration_list : declaration
 187                   | declaration_list declaration

 188  statement_list : statement
 189                 | statement_list statement

 190  expression_statement : ';'
 191                       | expression ';'

 192  selection_statement : IF '(' expression ')' statement
 193                      | IF '(' expression ')' statement ELSE statement
 194                      | SWITCH '(' expression ')' statement

 195  iteration_statement : WHILE '(' expression ')' statement
 196                      | DO statement WHILE '(' expression ')' ';'
 197                      | FOR '(' expression_statement expression_statement ')' statement
 198                      | FOR '(' expression_statement expression_statement expression ')' statement

 199  jump_statement : GOTO IDENTIFIER ';'
 200                 | CONTINUE ';'
 201                 | BREAK ';'
 202                 | RETURN ';'
 203                 | RETURN expression ';'

 204  translation_unit : external_declaration
 205                   | translation_unit external_declaration

 206  external_declaration : function_definition
 207                       | declaration

 208  function_definition : declaration_specifiers declarator declaration_list compound_statement
 209                      | declaration_specifiers declarator compound_statement
 210                      | declarator declaration_list compound_statement
 211                      | declarator compound_statement

本文来自优快云博客，转载请标明出处：http://blog.youkuaiyun.com/nomad2/archive/2007/06/05/1639177.aspx