Question

我正在尝试解析Windows头文件以提取函数原型。 Microsoft是Microsoft意味着函数原型不是常规的，易于解析的格式。常规参数通常（但并非总是）使用Microsoft的结构化注释语言进行注释，该结构化注释语言以以下划线开头和结尾的标识符开头，并且中间可能有下划线。 SAL标识符后面可以跟括号并包含各种编译时检查，但我不关心SAL的东西。例程通常用访问说明符注释，通常类似于WINAPI，APIENTRY等，但可能不止一个。在某些情况下，参数也仅由其类型指定。啧！

我的语法看起来像这样：

//
// Parse C function declarations from a header file
//

grammar FuncDef;

//
// Parser rules
//

start :
                func_def+
                ;

func_def :
                'extern'? ret_type = IDENTIFIER access = access_spec routine = IDENTIFIER '(' arg_list* ')' ';'
                ;

sal_statement :
                SAL_NAME SAL_EXPR?
                ;

access_spec :
                ('FAR' | 'PASCAL' | 'WINAPI' | 'APIENTRY' | 'WSAAPI' | 'WSPAPI')?
                ;

argument :
                sal_statement type = IDENTIFIER is_pointer = '*'? arg = IDENTIFIER
                ;

arg_list :
                argument (',' argument)*
                ;

hex_number :
                '0x' HEX_DIGIT+
                ;

//
// Lexer rules
//

INTEGER :           Digit+;
HEX_DIGIT :         [a-fA-F0-9];
SAL_NAME :          '_' Capital (Letter | '_')+? '_';           // Restricted form of IDENTIFIER, so it must be first
IDENTIFIER :        Id_chars+;
SAL_EXPR :          '(' ( ~( '(' | ')' ) | SAL_EXPR )* ')';     // We don't care about anything within a SAL expression, so eat everything within matched and nested parentheses
CPP_COMMENT :       '//' .*? '\r'? '\n'     -> channel (HIDDEN);
C_COMMENT :         '/*' .*? '*/'           -> channel (HIDDEN);

WS :                [ \t\r\n]+ -> skip;                 // Ignore all whitespace

fragment Id_chars : Letter | Digit | '_' | '$';
fragment Capital :  [A-Z];
fragment Letter :   [a-zA-Z];
fragment Digit :    [0-9];

我正在使用TestRig，并提供以下输入：

PVOID WINAPI routine ();

PVOID WINAPI routine (type param);

extern int PASCAL FAR __WSAFDIsSet(SOCKET fd, fd_set FAR *);

// comment
/*
Another comment*/

int
WSPAPI
WSCSetApplicationCategory(
    _Out_writes_bytes_to_(nNumberOfBytesToRead, *lpNumberOfBytesRead) LPBYTE lpBuffer,
    _In_ DWORD PathLength,
    _In_reads_opt_(ExtraLength) LPCWSTR Extra,
    _When_(pbCancel != NULL, _Pre_satisfies_(*pbCancel == FALSE))
        DWORD ExtraLength,
    _In_ DWORD PermittedLspCategories,
    _Out_opt_ DWORD * pPrevPermLspCat,
    _Out_ LPINT lpErrno
    );

我收到了这个输出：

[@0,0:4='PVOID',<IDENTIFIER>,1:0]
[@1,6:11='WINAPI',<'WINAPI'>,1:6]
[@2,13:19='routine',<IDENTIFIER>,1:13]
[@3,21:22='()',<SAL_EXPR>,1:21]
[@4,23:23=';',<';'>,1:23]
[@5,28:32='PVOID',<IDENTIFIER>,3:0]
[@6,34:39='WINAPI',<'WINAPI'>,3:6]
[@7,41:47='routine',<IDENTIFIER>,3:13]
[@8,49:60='(type param)',<SAL_EXPR>,3:21]
[@9,61:61=';',<';'>,3:33]
[@10,66:71='extern',<'extern'>,5:0]
[@11,73:75='int',<IDENTIFIER>,5:7]
[@12,77:82='PASCAL',<'PASCAL'>,5:11]
[@13,84:86='FAR',<'FAR'>,5:18]
[@14,88:99='__WSAFDIsSet',<IDENTIFIER>,5:22]
[@15,100:124='(SOCKET fd, fd_set FAR *)',<SAL_EXPR>,5:34]
[@16,125:125=';',<';'>,5:59]
[@17,130:141='// comment\r\n',<CPP_COMMENT>,channel=1,7:0]
[@18,142:162='/*\r\nAnother comment*/',<C_COMMENT>,channel=1,8:0]
[@19,167:169='int',<IDENTIFIER>,11:0]
[@20,172:177='WSPAPI',<'WSPAPI'>,12:0]
[@21,180:204='WSCSetApplicationCategory',<IDENTIFIER>,13:0]
[@22,205:568='(\r\n    _Out_writes_bytes_to_(nNumberOfBytesToRead, *lpNumberOfBytesRead) LPBYTE lpBuffer,\r\n    _In_ DWORD PathLength,\r\n    _In_reads_opt_(ExtraLength) LPCWSTR Extra,\r\n    _When_(pbCancel != NULL, _Pre_satisfies_(*pbCancel == FALSE))\r\nDWORD ExtraLength,\r\n    _In_ DWORD PermittedLspCategories,\r\n    _Out_opt_ DWORD * pPrevPermLspCat,\r\n    _Out_ LPINT lpErrno\r\n    )',<SAL_EXPR>,13:25]
[@23,569:569=';',<';'>,22:5]
[@24,572:571='<EOF>',<EOF>,23:0]
line 1:21 mismatched input '()' expecting '('
line 3:21 mismatched input '(type param)' expecting '('
line 5:18 extraneous input 'FAR' expecting IDENTIFIER
line 5:34 mismatched input '(SOCKET fd, fd_set FAR *)' expecting '('
line 13:25 mismatched input '(\r\n    _Out_writes_bytes_to_(nNumberOfBytesToRead, *lpNumberOfBytesRead) LPBYTE lpBuffer,\r\n    _In_ DWORD PathLength,\r\n    _In_reads_opt_(ExtraLength) LPCWSTR Extra,\r\n    _When_(pbCancel != NULL, _Pre_satisfies_(*pbCancel == FALSE))\r\nDWORD ExtraLength,\r\n    _In_ DWORD PermittedLspCategories,\r\n    _Out_opt_ DWORD * pPrevPermLspCat,\r\n    _Out_ LPINT lpErrno\r\n    )' expecting '('

我不明白为什么SAL_EXPR在第3和第8行匹配？如果SAL_NAME首先匹配，它应该匹配。

为什么SAL_NAME在第22行没有匹配？

Answer 1

我不明白为什么SAL_EXPR在第3和第8行匹配？如果SAL_NAME首先匹配，它应该匹配。

词法分析器对解析器规则一无所知，只对输入进行操作。它无法知道“如果SAL_NAME首先匹配，它应该只匹配一些东西”。

最好的方法可能是不把这个逻辑变成词法分析器，即只决定输入是SAL表达式还是解析器括号中的其他东西，而不是词法分析器。

Answer 2

这是正常运作的语法：

//
// Parse C function declarations from a header file
//

grammar FuncDef;

//
// Parser rules
//

start :
                func_def+
                ;

func_def :
                'extern'? ret_type = IDENTIFIER access = access_spec* routine = IDENTIFIER '(' arg_list* ')' ';'
                ;

sal_statement :
                SAL_NAME sal_expr?
                ;

sal_expr :
                '(' ( ~( '(' | ')' ) | sal_expr )* ')'      // We don't care about anything within a SAL expression, so eat everything within matched and nested parentheses
                ;

access_spec :
                ('FAR' | 'PASCAL' | 'WINAPI' | 'APIENTRY' | 'WSAAPI' | 'WSPAPI')
                ;

argument :
                sal_statement? type = IDENTIFIER access_spec? is_pointer = '*'? arg = IDENTIFIER?
            |   sal_statement
                ;

arg_list :
                argument (',' argument)*
                ;

//
// Lexer rules
//

SAL_NAME :          '_' Capital (Letter | '_')+ '_';            // Restricted form of IDENTIFIER, so it must be first
IDENTIFIER :        Id_chars+;
CPP_COMMENT :       '//' .*? '\r'? '\n'     -> channel (HIDDEN);
C_COMMENT :         '/*' .*? '*/'           -> channel (HIDDEN);
OPERATORS :         [&|=!><];
WS :                [ \t\r\n]+              -> skip;            // Ignore all whitespace

fragment Id_chars : Letter | Digit | '_' | '$';
fragment Capital :  [A-Z];
fragment Letter :   [a-zA-Z];
fragment Digit :    [0-9];

令牌匹配，但它不应该

2 个答案: