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#include "rc.h"
#include "parse.h"
static int advance(void);
// -----------------------------------------------------------------------
// lexer
struct Lexer
{
int c[2];
ushort doprompt;
char buf[BUFSIZ];
};
static struct Lexer lexer = { .c={0, EOF}, .doprompt=1 };
void
yyerror(char *msg)
{
print(errio, "\nrc: ");
if(lexer.buf[0] && lexer.buf[0]!='\n')
print(errio, "@ %q: ", lexer.buf);
print(errio, "%s\n", msg);
flush(errio);
while(lexer.c[0] !='\n' && lexer.c[0] != EOF)
advance();
}
int
readc(void)
{
int c;
static int peek = EOF;
if(peek!=EOF){
c = peek;
peek = EOF;
return c;
}
if(shell->flag.eof)
return EOF;
if(!prompt(&lexer.doprompt))
exit(1); // XXX: hack for signal handling right now...
c = get(shell->cmd.io);
lexer.doprompt = lexer.doprompt || c=='\n' || c==EOF;
if(c==EOF)
shell->flag.eof = 1;
return c;
}
static
int
peekc(void)
{
if(lexer.c[1] == EOF)
lexer.c[1] = readc();
return lexer.c[1];
}
static
int
advance(void)
{
int c = peekc();
lexer.c[0] = lexer.c[1], lexer.c[1] = EOF;
return c;
}
static
void
skipws(void)
{
int c;
for(;;){
c = peekc();
if(c== ' ' || c == '\t')
advance();
else
return;
}
}
static
void
skipnl(void)
{
int c;
for(;;){
c = peekc();
if(c== ' ' || c == '\t' || c == '\n')
advance();
else
return;
}
}
static
int
nextis(int c)
{
if(peekc()==c){
advance();
return 1;
}
return 0;
}
static
char *
putbyte(char *buf, int c)
{
if(!buf)
return buf;
if(buf == arrend(lexer.buf)){
fatal("lexer: out of buffer space");
return nil;
}
*buf++ = c;
return buf;
}
#define onebyte(c) ((c&0x80)==0x00)
#define twobyte(c) ((c&0xe0)==0xc0)
#define threebyte(c) ((c&0xf0)==0xe0)
#define fourbyte(c) ((c&0xf8)==0xf0)
static
char *
putrune(char *buf, int c)
{
buf = putbyte(buf, c);
if(onebyte(c))
return buf;
if(twobyte(c))
return putbyte(buf,c);
if(threebyte(c)){
buf = putbyte(buf,c);
return putbyte(buf,c);
}
if(fourbyte(c)){
buf = putbyte(buf,c);
buf = putbyte(buf,c);
return putbyte(buf,c);
}
fatal("malformed utf8 stream");
return nil;
}
// -----------------------------------------------------------------------
// exported functions
int
iswordchar(int c)
{
return !strchr("\n \t#;&|^$=`'{}()<>", c) && c!=EOF;
}
int
yylex(void)
{
int c;
Tree *node;
char *w = lexer.buf;
yylval.tree = nil;
skipws();
switch(c=advance()){
case EOF:
return EOF;
case '&':
lexer.buf[0] = '&';
lexer.buf[1] = 0;
return '&';
default:
;
}
if(!iswordchar(c))
return c;
for(;;){
w = putrune(w, c);
c = peekc();
if(!iswordchar(c))
break;
advance();
}
w[0] = 0;
node = token(Tword, lexer.buf);
yylval.tree = node;
return node->type;
}
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