1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
%{
/* $NetBSD: scan.l,v 1.2 1994/12/02 00:43:41 phil Exp $ */
/* scan.l: the (f)lex description file for the scanner. */
/* This file is part of bc written for MINIX.
Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
This program 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.
This program 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 this program; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
You may contact the author by:
e-mail: phil@cs.wwu.edu
us-mail: Philip A. Nelson
Computer Science Department, 9062
Western Washington University
Bellingham, WA 98226-9062
*************************************************************************/
#include "bcdefs.h"
#include "y.tab.h"
#include "global.h"
#include "proto.h"
/* Using flex, we can ask for a smaller input buffer. With lex, this
does nothing! */
#ifdef SMALL_BUF
#undef YY_READ_BUF_SIZE
#define YY_READ_BUF_SIZE 512
#endif
/* We want to define our own yywrap. */
#undef yywrap
_PROTOTYPE(int yywrap, (void));
/* MINIX returns from read with < 0 if SIGINT is encountered.
In flex, we can redefine YY_INPUT to the following. In lex, this
does nothing! */
#include <errno.h>
#undef YY_INPUT
#define YY_INPUT(buf,result,max_size) \
while ( (result = read( fileno(yyin), (char *) buf, max_size )) < 0 ) \
if (errno != EINTR) \
YY_FATAL_ERROR( "read() in flex scanner failed" );
%}
DIGIT [0-9A-F]
LETTER [a-z]
%%
define return(Define);
break return(Break);
quit return(Quit);
length return(Length);
return return(Return);
for return(For);
if return(If);
while return(While);
sqrt return(Sqrt);
scale return(Scale);
ibase return(Ibase);
obase return(Obase);
auto return(Auto);
else return(Else);
read return(Read);
halt return(Halt);
last return(Last);
warranty return(Warranty);
continue return(Continue);
print return(Print);
limits return(Limits);
"." {
#ifdef DOT_IS_LAST
return(Last);
#else
yyerror ("illegal character: %s",yytext);
#endif
}
"+"|"-"|";"|"("|")"|"{"|"}"|"["|"]"|","|"^" { yylval.c_value = yytext[0];
return((int)yytext[0]); }
&& { return(AND); }
\|\| { return(OR); }
"!" { return(NOT); }
"*"|"/"|"%" { yylval.c_value = yytext[0]; return(MUL_OP); }
"="|\+=|-=|\*=|\/=|%=|\^= { yylval.c_value = yytext[0]; return(ASSIGN_OP); }
=\+|=-|=\*|=\/|=%|=\^ {
#ifdef OLD_EQ_OP
char warn_save;
warn_save = warn_not_std;
warn_not_std = TRUE;
warn ("Old fashioned =<op>");
warn_not_std = warn_save;
yylval.c_value = yytext[1];
#else
yylval.c_value = '=';
yyless (1);
#endif
return(ASSIGN_OP);
}
==|\<=|\>=|\!=|"<"|">" { yylval.s_value = strcopyof(yytext); return(REL_OP); }
\+\+|-- { yylval.c_value = yytext[0]; return(INCR_DECR); }
"\n" { line_no++; return(NEWLINE); }
\\\n { line_no++; /* ignore a "quoted" newline */ }
[ \t]+ { /* ignore spaces and tabs */ }
"/*" {
int c;
for (;;)
{
while ( ((c=input()) != '*') && (c != EOF))
/* eat it */
if (c == '\n') line_no++;
if (c == '*')
{
while ( (c=input()) == '*') /* eat it*/;
if (c == '/') break; /* at end of comment */
if (c == '\n') line_no++;
}
if (c == EOF)
{
fprintf (stderr,"EOF encountered in a comment.\n");
break;
}
}
}
[a-z][a-z0-9_]* { yylval.s_value = strcopyof(yytext); return(NAME); }
\"[^\"]*\" {
unsigned char *look;
int count = 0;
yylval.s_value = strcopyof(yytext);
for (look = yytext; *look != 0; look++)
{
if (*look == '\n') line_no++;
if (*look == '"') count++;
}
if (count != 2) yyerror ("NUL character in string.");
return(STRING);
}
{DIGIT}({DIGIT}|\\\n)*("."({DIGIT}|\\\n)*)?|"."(\\\n)*{DIGIT}({DIGIT}|\\\n)* {
unsigned char *src, *dst;
int len;
/* remove a trailing decimal point. */
len = strlen(yytext);
if (yytext[len-1] == '.')
yytext[len-1] = 0;
/* remove leading zeros. */
src = yytext;
dst = yytext;
while (*src == '0') src++;
if (*src == 0) src--;
/* Copy strings removing the newlines. */
while (*src != 0)
{
if (*src == '\\')
{
src++; src++;
line_no++;
}
else
*dst++ = *src++;
}
*dst = 0;
yylval.s_value = strcopyof(yytext);
return(NUMBER);
}
. {
if (yytext[0] < ' ')
yyerror ("illegal character: ^%c",yytext[0] + '@');
else
if (yytext[0] > '~')
yyerror ("illegal character: \\%3d", (int) yytext[0]);
else
yyerror ("illegal character: %s",yytext);
}
%%
/* This is the way to get multiple files input into lex. */
int
yywrap()
{
if (!open_new_file ()) return (1); /* EOF on standard in. */
return (0); /* We have more input. */
}
|
