usage: Print metavariables in SHOUTY letters.

[sw-tools] / src / sw_env.h

/* -*-c-*-
 *
 * $Id: sw_env.h,v 1.3 2004/04/08 01:52:19 mdw Exp $
 *
 * Mangling of environment variables
 *
 * (c) 1999 EBI
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of sw-tools.
 *
 * sw-tools is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * sw-tools is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with sw-tools; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef SW_ENV_H
#define SW_ENV_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <stdio.h>

#include <mLib/dstr.h>
#include <mLib/env.h>
#include <mLib/sym.h>

/*----- Important constants -----------------------------------------------*/

enum {
  ENV_OK = 0,				/* Parsed OK */
  ENV_EOF,				/* End-of-file encountered */
  ENV_VCHAR,				/* Bad character in variable name */
  ENV_SUBST,				/* Bad parameter substitution */
  ENV_QUOTE,				/* Mismatched quote */
  ENV_BRACE,				/* Missing brace character */
  ENV_SYSTEM,				/* System error (see @errno@) */
  ENV_INTERNAL				/* Internal error */
};

enum {
  EVF_INCSPC = 1,			/* Allow spaces in values */
  EVF_BACKTICK = 2,			/* Make backtick self-delimiting */
  EVF_SKIP = 4,				/* Skipping this section of text */
  EVF_INITSPC = 8			/* Allow and ignore leading space */
};

/*----- Functions provided ------------------------------------------------*/

/* --- @env_error@ --- *
 *
 * Arguments:	@int e@ = error code
 *
 * Returns:	String representation of error.
 *
 * Use:		Transforms an error into something a user can understand.
 */

extern const char *env_error(int /*e*/);

/* --- @env_var@ --- *
 *
 * Arguments:	@sym_table *t@ = pointer to symbol table
 *		@FILE *fp@ = pointer to stream to read from
 *		@dstr *d@ = pointer to output variable
 *
 * Returns:	One of the @ENV_@ constants.
 *
 * Use:		Scans a variable name from the input stream.
 */

extern int env_var(sym_table */*t*/, FILE */*fp*/, dstr */*d*/);

/* --- @env_value@ --- *
 *
 * Arguments:	@sym_table *t@ = pointer to symbol table
 *		@FILE *fp@ = pointer to stream to read from
 *		@dstr *d@ = pointer to output variable
 *		@unsigned f@ = various interesting flags
 *
 * Returns:	0 if OK, @EOF@ if end-of-file encountered, or >0 on error.
 *
 * Use:		Scans a value from the input stream.  The value read may be
 *		quoted in a Bourne-shell sort of a way, and contain Bourne-
 *		shell-like parameter substitutions.  Some substitutions
 *		aren't available because they're too awkward to implement.
 */

extern int env_value(sym_table */*t*/, FILE */*fp*/,
		     dstr */*d*/, unsigned /*f*/);

/* --- @env_read@ --- *
 *
 * Arguments:	@sym_table *t@ = pointer to symbol table
 *		@FILE *fp@ = file handle to read
 *		@unsigned f@ = various flags
 *
 * Returns:	Zero if OK, @EOF@ for end-of-file, or error code.
 *
 * Use:		Reads the environment assignment statements in the file.
 */

extern int env_read(sym_table */*t*/, FILE */*fp*/, unsigned /*f*/);

/* --- @env_file@ --- *
 *
 * Arguments:	@sym_table *t@ = pointer to symbol table
 *		@const char *name@ = pointer to filename
 *
 * Returns:	Zero if OK, or an error code.
 *
 * Use:		Reads a named file of environment assignments.
 */

extern int env_file(sym_table */*t*/, const char */*name*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif