[m-dev.] for review: print parts of variables

[Fergus Henderson]

On 18-Jul-2000, Zoltan Somogyi <zs at cs.mu.OZ.AU> wrote:
> Allow users to request the printouts of only parts of variables.
> Instead of the old sequence
> 
> 	browse Varnameornum
> 	^1^2^3^4
> 	p
> 	^D
> 
> users can now just a single command: print Varnameornum^1^2^3^4, or print
> Varnameornum/1/2/3/4. The required component is given by a sequence of
> argument numbers, separated by ^s or /s.

That sounds like a good idea.

> +++ mercury_trace_util.c	Mon Jul 17 17:18:48 2000
> @@ -0,0 +1,38 @@
> +
> +/*
> +** Copyright (C) 2000 The University of Melbourne.
> +** This file may only be copied under the terms of the GNU Library General
> +** Public License - see the file COPYING.LIB in the Mercury distribution.
> +*/
> +
> +/*
> +** This file contains utility functions for debugger.
> +**
> +** Author: zs.
> +*/
> +
> +#include "mercury_imp.h"
> +#include "mercury_trace_util.h"
> +
> +#include <ctype.h>
> +
> +bool	MR_trace_is_number(const char *word, int *value);
> +
> +bool
> +MR_trace_is_number(const char *word, int *value)
> +{

Why is that declared before it is defined?
The declaration should be in the header file,
so there should be no need for a duplicate declaration here.

> @@ -628,25 +632,96 @@
>  }
>  
>  const char *
> +MR_trace_parse_browse_one(FILE *out, char *word_spec, MR_Browser browser,
> +	bool must_be_unique)
> +{
> +	MR_Var_Spec	var_spec;
> +	char		*path;
> +	char		*s;
> +	int		n;
> +
> +	s = word_spec;
> +	while (*s != '\0' && *s != '^' && *s != '/') {
> +		s++;
> +	}
> +
> +	if (*s == '\0') {

You could write that more concisely as

	s = strpbrk(word_spec, "^/");

	if (s == NULL) {

> @@ -685,6 +777,26 @@
>  	return NULL;
>  }
>  
> +#define	BAD_PATH_BUFFER_SIZE	128
> +#define	BAD_PATH_MSG_PREFIX	"the path "
> +#define	BAD_PATH_MSG_SUFFIX	" does not exist"
> +
> +static const char *
> +MR_trace_bad_path(char *path)
> +{
> +	static	char	buffer[BAD_PATH_BUFFER_SIZE];
> +
> +	if (strlen(BAD_PATH_MSG_PREFIX) + strlen(path) +
> +		strlen(BAD_PATH_MSG_SUFFIX) < BAD_PATH_BUFFER_SIZE)
> +	{
> +		sprintf(buffer, "%s%s%s", BAD_PATH_MSG_PREFIX, path,
> +			BAD_PATH_MSG_SUFFIX);
> +		return buffer;
> +	} else {
> +		return "the given path does not exist";
> +	}
> +}

s/char *path/const char *path/

It might be nice to double-check all the other places where you use
`char *' rather than `const char *'.

> +/* ML_arg() is defined in std_util.m */
> +extern	bool 	ML_arg(MR_TypeInfo term_type_info, Word *term, int arg_index,
> +			MR_TypeInfo *arg_type_info_ptr, Word **arg_ptr);

Rather than declaring this manually, it would be better to include the header file:

	#ifdef MR_HIGHLEVEL_CODE
	  #include "mercury.std_util.h"
	#else
	  #include "std_util.h"
	#endif

Apart from that, this change looks fine.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.
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