X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/61e3dbdf67c571ec4973ab19475ced6a438ab8df..75d4484771fe55c41858ed1c289388ebde6ee8f0:/conf.h diff --git a/conf.h b/conf.h index 1704587..f9e25e9 100644 --- a/conf.h +++ b/conf.h @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: conf.h,v 1.2 1999/07/26 23:28:39 mdw Exp $ + * $Id: conf.h,v 1.7 2002/02/22 23:42:56 mdw Exp $ * * Configuration parsing * @@ -29,6 +29,25 @@ /*----- Revision history --------------------------------------------------* * * $Log: conf.h,v $ + * Revision 1.7 2002/02/22 23:42:56 mdw + * `fw'-specific configuration code moved out. This file might become part + * of a library some day. + * + * Revision 1.6 2002/01/13 14:48:16 mdw + * Make delimiters be a property of a scanner. Change the delimiter- + * changing functions' names. + * + * Revision 1.5 1999/10/22 22:46:44 mdw + * Improve documentation for conf_enum. + * + * Revision 1.4 1999/08/19 18:32:48 mdw + * Improve lexical analysis. In particular, `chmod' patterns don't have to + * be quoted any more. + * + * Revision 1.3 1999/07/27 18:30:14 mdw + * Improve documentation and layout for @CONF_BEGIN@ and friends. Remove + * irritating warning about unused label by introducing a spurious `goto'. + * * Revision 1.2 1999/07/26 23:28:39 mdw * Major reconstruction work for new design. * @@ -59,6 +78,21 @@ /*----- Functions provided ------------------------------------------------*/ +/* --- @conf_undelim@ --- * + * + * Arguments: @scanner *sc@ = pointer to scanner definition + * @const char *d, *dd@ = pointer to characters to escape + * + * Returns: --- + * + * Use: Modifies the tokenizer. Characters in the first list will + * always be considered to begin a word. Characters in the + * second list will always be allowed to continue a word. + */ + +extern void conf_undelim(scanner */*sc*/, + const char */*d*/, const char */*dd*/); + /* --- @token@ --- * * * Arguments: @scanner *sc@ = pointer to scanner definition @@ -83,6 +117,18 @@ extern int token(scanner */*sc*/); extern void error(scanner */*sc*/, const char */*msg*/, ...); +/* --- @pushback@ --- * + * + * Arguments: @scanner *sc@ = pointer to scanner definition + * + * Returns: --- + * + * Use: Pushes the current token back. This is normally a precursor + * to pushing a new scanner source. + */ + +extern void pushback(scanner */*sc*/); + /* --- @conf_enum@ --- * * * Arguments: @scanner *sc@ = pointer to a scanner object @@ -93,9 +139,15 @@ extern void error(scanner */*sc*/, const char */*msg*/, ...); * Returns: Index into list, zero-based, or @-1@. * * Use: Checks whether the current token is a string which matches - * one of the comma-separated items given. If not, an error is - * reported; otherwise the index of the matched item is - * returned. + * one of the comma-separated items given. The return value is + * the index (zero-based) of the matched string in the list. + * + * The flags control the behaviour if no exact match is found. + * If @ENUM_ABBREV@ is set, and the current token is a left + * substring of exactly one of the possibilities, then that one + * is chosen. If @ENUM_NONE@ is set, the value @-1@ is + * returned; otherwise an error is reported and the program is + * terminated. */ #define ENUM_ABBREV 1u @@ -125,13 +177,21 @@ extern int conf_enum(scanner */*sc*/, const char */*list*/, extern int conf_prefix(scanner */*sc*/, const char */*p*/); -/* --- @CONF_BEGIN@, @CONF_ACCEPT@, @CONF_END@ --- * +/* --- @CONF_BEGIN@, @CONF_END@ --- * * * Arguments: @sc@ = scanner to read from * @prefix@ = prefix to scan for * @desc@ = description of what we're parsing * - * Use: Bracket an options parsing routine. + * Use: Bracket an options parsing routine. The current token is + * checked to see whether it matches the prefix. If so, it is + * removed and the following token examined. If that's a `.' + * then it's removed. If it's a `{' then the enclosed + * option-parsing code is executed in a loop until a matching + * '}' is found. If the options parser doesn't accept an + * option, the behaviour is dependent on whether a prefix was + * seen: if so, an error is reported; otherwse a zero return is + * made. */ #define CS_PLAIN 0 @@ -143,6 +203,9 @@ extern int conf_prefix(scanner */*sc*/, const char */*p*/); scanner *_conf_sc = (sc); \ const char *_conf_desc = (desc); \ int _conf_state = CS_PLAIN; \ + \ + /* --- Read the initial prefix --- */ \ + \ if (_conf_sc->t == CTOK_WORD && \ strcmp(_conf_sc->d.buf, (prefix)) == 0) { \ token(_conf_sc); \ @@ -154,15 +217,22 @@ extern int conf_prefix(scanner */*sc*/, const char */*p*/); _conf_state = CS_BRACE; \ } \ } \ + \ + /* --- Ensure the next token is a word --- */ \ + \ if (_conf_sc->t != CTOK_WORD) \ error(_conf_sc, "parse error, expected option keyword"); \ do { -#define CONF_ACCEPT goto _conf_accept -#define CONF_REJECT goto _conf_reject -#define CONF_QUAL (_conf_state != CS_PLAIN) - #define CONF_END \ + \ + /* --- Reject an option --- * \ + * \ + * We could get here as a result of an explicit @CONF_REJECT@ or \ + * because the option wasn't accepted. \ + */ \ + \ + goto _conf_reject; \ _conf_reject: \ if (_conf_state == CS_PLAIN) \ _conf_state = CS_UNKNOWN; \ @@ -170,19 +240,54 @@ extern int conf_prefix(scanner */*sc*/, const char */*p*/); error(_conf_sc, "unknown %s option `%s'", \ _conf_desc, _conf_sc->d.buf); \ } \ + \ + /* --- Accept an option --- * \ + * \ + * It's safe to drop through from above. Either an error will have \ + * been reported, or the state is not @CS_BRACE@. \ + */ \ + \ _conf_accept: \ if (_conf_state == CS_BRACE && _conf_sc->t == ';') \ token(_conf_sc); \ } while (_conf_state == CS_BRACE && _conf_sc->t == CTOK_WORD); \ + \ + /* --- Check for a closing brace --- */ \ + \ if (_conf_state == CS_BRACE) { \ if (_conf_sc->t == '}') \ token(_conf_sc); \ else \ error(_conf_sc, "parse error, expected `}'"); \ } \ + \ + /* --- Return an appropriate value --- */ \ + \ return (_conf_state != CS_UNKNOWN); \ } while (0) +/* --- @CONF_ACCEPT@, @CONF_REJECT@ --- * + * + * Arguments: --- + * + * Use: Within an options parser (between @CONF_BEGIN@ and + * @CONF_END@), accept or reject an option. + */ + +#define CONF_ACCEPT goto _conf_accept +#define CONF_REJECT goto _conf_reject + +/* --- @CONF_QUAL@ --- * + * + * Arguments: --- + * + * Use: Evaluates to a nonzero value if the current option is + * qualified. This can be used to decide whether abbreviations + * for options should be accepted. + */ + +#define CONF_QUAL (_conf_state != CS_PLAIN) + /* --- @conf_name@ --- * * * Arguments: @scanner *sc@ = pointer to scanner @@ -202,17 +307,6 @@ extern int conf_prefix(scanner */*sc*/, const char */*p*/); extern void conf_name(scanner */*sc*/, char /*delim*/, dstr */*d*/); -/* --- @conf_parse@ --- * - * - * Arguments: @scanner *sc@ = pointer to a scanner structure - * - * Returns: --- - * - * Use: Parses a configuration file fragment from the scanner - */ - -extern void conf_parse(scanner *sc); - /*----- That's all, folks -------------------------------------------------*/ #ifdef __cplusplus