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ack/lang/m2/comp/LLlex.c
ceriel da54801353 newer version
1986-11-26 16:40:45 +00:00

507 lines
9 KiB
C
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/* L E X I C A L A N A L Y S E R F O R M O D U L A - 2 */
#include "debug.h"
#include "idfsize.h"
#include "numsize.h"
#include "strsize.h"
#include <alloc.h>
#include <em_arith.h>
#include <em_label.h>
#include <assert.h>
#include "input.h"
#include "f_info.h"
#include "Lpars.h"
#include "class.h"
#include "idf.h"
#include "type.h"
#include "LLlex.h"
#include "const.h"
#include "warning.h"
long str2long();
struct token dot,
aside;
struct type *toktype;
int idfsize = IDFSIZE;
#ifdef DEBUG
extern int cntlines;
#endif
static int eofseen;
STATIC
SkipComment()
{
/* Skip Modula-2 comments (* ... *).
Note that comments may be nested (par. 3.5).
*/
register int ch;
register int CommentLevel = 0;
LoadChar(ch);
for (;;) {
if (class(ch) == STNL) {
LineNumber++;
#ifdef DEBUG
cntlines++;
#endif
}
else if (ch == '(') {
LoadChar(ch);
if (ch == '*') CommentLevel++;
else continue;
}
else if (ch == '*') {
LoadChar(ch);
if (ch == ')') {
CommentLevel--;
if (CommentLevel < 0) break;
}
else continue;
}
else if (ch == EOI) {
lexerror("unterminated comment");
break;
}
LoadChar(ch);
}
}
STATIC struct string *
GetString(upto)
{
/* Read a Modula-2 string, delimited by the character "upto".
*/
register int ch;
register struct string *str = (struct string *)
Malloc((unsigned) sizeof(struct string));
register char *p;
register int len;
len = ISTRSIZE;
str->s_str = p = Malloc((unsigned int) ISTRSIZE);
while (LoadChar(ch), ch != upto) {
if (class(ch) == STNL) {
lexerror("newline in string");
LineNumber++;
#ifdef DEBUG
cntlines++;
#endif
break;
}
if (ch == EOI) {
lexerror("end-of-file in string");
break;
}
*p++ = ch;
if (p - str->s_str == len) {
str->s_str = Srealloc(str->s_str,
(unsigned int) len + RSTRSIZE);
p = str->s_str + len;
len += RSTRSIZE;
}
}
str->s_length = p - str->s_str;
while (p - str->s_str < len) *p++ = '\0';
if (str->s_length == 0) str->s_length = 1;
/* ??? string length at least 1 ??? */
return str;
}
static char *s_error = "illegal line directive";
STATIC int
getch()
{
register int ch;
for (;;) {
LoadChar(ch);
if ((ch & 0200) && ch != EOI) {
error("non-ascii '\\%03o' read", ch & 0377);
continue;
}
break;
}
if (ch == EOI) {
eofseen = 1;
return '\n';
}
return ch;
}
STATIC
linedirective() {
/* Read a line directive
*/
register int ch;
register int i = 0;
char buf[IDFSIZE + 2];
register char *c = buf;
do { /*
* Skip to next digit
* Do not skip newlines
*/
ch = getch();
if (class(ch) == STNL) {
LineNumber++;
error(s_error);
return;
}
} while (class(ch) != STNUM);
do {
i = i*10 + (ch - '0');
ch = getch();
} while (class(ch) == STNUM);
while (ch != '"' && class(ch) != STNL) ch = getch();
if (ch == '"') {
c = buf;
do {
*c++ = ch = getch();
if (class(ch) == STNL) {
LineNumber++;
error(s_error);
return;
}
} while (ch != '"');
*--c = '\0';
do {
ch = getch();
} while (class(ch) != STNL);
/*
* Remember the file name
*/
if (!eofseen && strcmp(FileName,buf)) {
FileName = Salloc(buf,(unsigned) strlen(buf) + 1);
}
}
if (eofseen) {
error(s_error);
return;
}
LineNumber = i;
}
int
LLlex()
{
/* LLlex() is the Lexical Analyzer.
The putting aside of tokens is taken into account.
*/
register struct token *tk = &dot;
char buf[(IDFSIZE > NUMSIZE ? IDFSIZE : NUMSIZE) + 2];
register int ch, nch;
toktype = error_type;
if (ASIDE) { /* a token is put aside */
*tk = aside;
ASIDE = 0;
return tk->tk_symb;
}
tk->tk_lineno = LineNumber;
again2:
if (eofseen) {
eofseen = 0;
ch = EOI;
}
else {
again:
LoadChar(ch);
again1:
if ((ch & 0200) && ch != EOI) {
error("non-ascii '\\%03o' read", ch & 0377);
goto again;
}
}
switch (class(ch)) {
case STNL:
LineNumber++;
#ifdef DEBUG
cntlines++;
#endif
tk->tk_lineno++;
LoadChar(ch);
if (ch != '#') goto again1;
linedirective();
goto again2;
case STSKIP:
goto again;
case STGARB:
if ((unsigned) ch - 040 < 0137) {
lexerror("garbage char %c", ch);
}
else lexerror("garbage char \\%03o", ch);
goto again;
case STSIMP:
if (ch == '(') {
LoadChar(nch);
if (nch == '*') {
SkipComment();
goto again;
}
else if (nch == EOI) eofseen = 1;
else PushBack(nch);
}
return tk->tk_symb = ch;
case STCOMP:
LoadChar(nch);
switch (ch) {
case '.':
if (nch == '.') {
return tk->tk_symb = UPTO;
}
break;
case ':':
if (nch == '=') {
return tk->tk_symb = BECOMES;
}
break;
case '<':
if (nch == '=') {
return tk->tk_symb = LESSEQUAL;
}
if (nch == '>') {
lexwarning(W_STRICT, "'<>' is old-fashioned; use '#'");
return tk->tk_symb = '#';
}
break;
case '>':
if (nch == '=') {
return tk->tk_symb = GREATEREQUAL;
}
break;
default :
crash("(LLlex, STCOMP)");
}
if (nch == EOI) eofseen = 1;
else PushBack(nch);
return tk->tk_symb = ch;
case STIDF:
{
register char *tag = &buf[0];
register struct idf *id;
do {
if (tag - buf < idfsize) *tag++ = ch;
LoadChar(ch);
} while(in_idf(ch));
if (ch == EOI) eofseen = 1;
else PushBack(ch);
*tag++ = '\0';
tk->TOK_IDF = id = str2idf(buf, 1);
return tk->tk_symb = id->id_reserved ? id->id_reserved : IDENT;
}
case STSTR: {
register struct string *str = GetString(ch);
if (str->s_length == 1) {
tk->TOK_INT = *(str->s_str) & 0377;
toktype = char_type;
free(str->s_str);
free((char *) str);
}
else {
tk->tk_data.tk_str = str;
toktype = standard_type(T_STRING, 1, str->s_length);
}
return tk->tk_symb = STRING;
}
case STNUM:
{
/* The problem arising with the "parsing" of a number
is that we don't know the base in advance so we
have to read the number with the help of a rather
complex finite automaton.
*/
enum statetp {Oct,Hex,Dec,OctEndOrHex,End,OptReal,Real};
register enum statetp state;
register int base;
register char *np = &buf[1];
/* allow a '-' to be added */
buf[0] = '-';
*np++ = ch;
state = is_oct(ch) ? Oct : Dec;
LoadChar(ch);
for (;;) {
switch(state) {
case Oct:
while (is_oct(ch)) {
if (np < &buf[NUMSIZE]) *np++ = ch;
LoadChar(ch);
}
if (ch == 'B' || ch == 'C') {
base = 8;
state = OctEndOrHex;
break;
}
/* Fall Through */
case Dec:
base = 10;
while (is_dig(ch)) {
if (np < &buf[NUMSIZE]) {
*np++ = ch;
}
LoadChar(ch);
}
if (is_hex(ch)) state = Hex;
else if (ch == '.') state = OptReal;
else {
state = End;
if (ch == 'H') base = 16;
else if (ch == EOI) eofseen = 1;
else PushBack(ch);
}
break;
case Hex:
while (is_hex(ch)) {
if (np < &buf[NUMSIZE]) *np++ = ch;
LoadChar(ch);
}
base = 16;
state = End;
if (ch != 'H') {
lexerror("H expected after hex number");
if (ch == EOI) eofseen = 1;
else PushBack(ch);
}
break;
case OctEndOrHex:
if (np < &buf[NUMSIZE]) *np++ = ch;
LoadChar(ch);
if (ch == 'H') {
base = 16;
state = End;
break;
}
if (is_hex(ch)) {
state = Hex;
break;
}
if (ch == EOI) eofseen = 1;
else PushBack(ch);
ch = *--np;
*np++ = '\0';
base = 8;
/* Fall through */
case End:
*np++ = '\0';
tk->TOK_INT = str2long(&buf[1], base);
if (ch == 'C' && base == 8) {
toktype = char_type;
if (tk->TOK_INT<0 || tk->TOK_INT>255) {
lexwarning(W_ORDINARY, "character constant out of range");
}
}
else if (tk->TOK_INT>=0 &&
tk->TOK_INT<=max_int) {
toktype = intorcard_type;
}
else toktype = card_type;
return tk->tk_symb = INTEGER;
case OptReal:
/* The '.' could be the first of the '..'
token. At this point, we need a
look-ahead of two characters.
*/
LoadChar(ch);
if (ch == '.') {
/* Indeed the '..' token
*/
PushBack(ch);
PushBack(ch);
state = End;
base = 10;
break;
}
state = Real;
break;
}
if (state == Real) break;
}
/* a real real constant */
if (np < &buf[NUMSIZE]) *np++ = '.';
while (is_dig(ch)) {
/* Fractional part
*/
if (np < &buf[NUMSIZE]) *np++ = ch;
LoadChar(ch);
}
if (ch == 'E') {
/* Scale factor
*/
if (np < &buf[NUMSIZE]) *np++ = 'E';
LoadChar(ch);
if (ch == '+' || ch == '-') {
/* Signed scalefactor
*/
if (np < &buf[NUMSIZE]) *np++ = ch;
LoadChar(ch);
}
if (is_dig(ch)) {
do {
if (np < &buf[NUMSIZE]) *np++ = ch;
LoadChar(ch);
} while (is_dig(ch));
}
else {
lexerror("bad scale factor");
}
}
*np++ = '\0';
if (ch == EOI) eofseen = 1;
else PushBack(ch);
if (np >= &buf[NUMSIZE]) {
tk->TOK_REL = Salloc("0.0", 5);
lexerror("floating constant too long");
}
else tk->TOK_REL = Salloc(buf, np - buf) + 1;
toktype = real_type;
return tk->tk_symb = REAL;
/*NOTREACHED*/
}
case STEOI:
return tk->tk_symb = -1;
case STCHAR:
default:
crash("(LLlex) Impossible character class");
/*NOTREACHED*/
}
/*NOTREACHED*/
}
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