1/* Readline support for calc program.
2
3Copyright 2000, 2001 Free Software Foundation, Inc.
4
5This file is part of the GNU MP Library.
6
7This program is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free Software
9Foundation; either version 3 of the License, or (at your option) any later
10version.
11
12This program is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
14PARTICULAR PURPOSE.  See the GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License along with
17this program.  If not, see http://www.gnu.org/licenses/.  */
18
19#include "calc-common.h"
20
21#if WITH_READLINE
22#include <stdio.h>   /* for FILE for old versions of readline/readline.h */
23#include <stdlib.h>  /* for free */
24#include <string.h>  /* for strdup */
25#include <unistd.h>  /* for isatty */
26#include <readline/readline.h>
27#include <readline/history.h>
28
29#include "gmp.h"
30
31
32/* change this to "#define TRACE(x) x" for a few diagnostics */
33#define TRACE(x)
34
35
36#define MIN(x,y) ((x) < (y) ? (x) : (y))
37
38char *
39calc_completion_entry (const char *text, int state)
40{
41  static int  index, len;
42  char  *name;
43
44  if (!state)
45    {
46      index = 0;
47      len = strlen (text);
48    }
49  TRACE (printf ("calc_completion_entry %s %d, index=%d len=%d\n",
50		 text, state, index, len));
51  while ((name = calc_keywords[index].name) != NULL)
52    {
53      index++;
54      if (memcmp (name, text, len) == 0)
55	return (strdup (name));
56    }
57  return NULL;
58}
59
60void
61calc_init_readline (void)
62{
63  /* By default use readline when the input is a tty.  It's a bit contrary
64     to the GNU interface conventions to make the behaviour depend on where
65     the input is coming from, but this is pretty convenient.  */
66  if (calc_option_readline == -1)
67    {
68      calc_option_readline = isatty (fileno (stdin));
69      TRACE (printf ("calc_option_readline %d\n", calc_option_readline));
70    }
71
72  if (calc_option_readline)
73    {
74      printf ("GNU MP demo calculator program, gmp version %s\n", gmp_version);
75      printf ("Type \"help\" for help.\n");
76      rl_readline_name = "gmp-calc";
77      rl_completion_entry_function = calc_completion_entry;
78    }
79}
80
81
82/* This function is supposed to return YY_NULL to indicate EOF, but that
83   constant is only in calclex.c and we don't want to clutter calclex.l with
84   this readline stuff, so instead just hard code 0 for YY_NULL.  That's
85   it's defined value on unix anyway.  */
86
87int
88calc_input (char *buf, size_t max_size)
89{
90  if (calc_option_readline)
91    {
92      static char    *line = NULL;
93      static size_t  line_size = 0;
94      static size_t  upto = 0;
95      size_t         copy_size;
96
97      if (upto >= line_size)
98	{
99	  if (line != NULL)
100	    free (line);
101
102	  line = readline (calc_more_input ? "more> " : "> ");
103	  calc_more_input = 1;
104	  if (line == NULL)
105	    return 0;
106	  TRACE (printf ("readline: %s\n", line));
107
108	  if (line[0] != '\0')
109	    add_history (line);
110
111	  line_size = strlen (line);
112	  line[line_size] = '\n';
113	  line_size++;
114	  upto = 0;
115	}
116
117      copy_size = MIN (line_size-upto, max_size);
118      memcpy (buf, line+upto, copy_size);
119      upto += copy_size;
120      return copy_size;
121    }
122  else
123    {
124      /* not readline */
125      return fread (buf, 1, max_size, stdin);
126    }
127}
128
129
130/* This redefined input() might let a traditional lex use the readline
131   support here.  Apparently POSIX doesn't specify whether an override like
132   this will work, so maybe it'll work or maybe it won't.  This function is
133   also not particularly efficient, but don't worry about that, since flex
134   is the preferred parser.  */
135
136int
137input (void)
138{
139  char  c;
140  if (calc_input (&c, 1) != 1)
141    return EOF;
142  else
143    return (int) c;
144}
145
146#endif /* WITH_READLINE */
147