void literal() {
if (lookahead == TRUE_T) {
match(TRUE_T);
emit("1");
} else if (lookahead == FALSE_T) {
match(FALSE_T);
emit("0");
} else if (lookahead == ID) {
symtable_record_ptr rec = symtable_get(token_value_str);
match(ID);
char s[33];
sprintf(s, "%d", rec->value);
emit(s);
} else {
char s[33];
sprintf(s, "%d", token_value);
match(NUM);
emit(s);
}
}
/*
* Export a variable in our symbol table to the environment.
*/
int builtin_export(int argc, char **argv, int in, int out, int err){
char *symdata;
/* Ignore the name of the command. */
argc--;
argv++;
/* Now attempt to export each passed argument. */
while ( *argv ){
symdata = symtable_get(*argv);
setenv(*argv, symdata, 1);
argv++;
}
return RSH_OK;
}
token lex() {
int state = 0;
// remove last token from buffer.
int n = BUFFER_SIZE - forward;
strncpy(buffer, buffer+forward, n);
buffer[n] = '\0';
lexeme_beginning = 0;
forward = 0;
int buffer_end = strlen(buffer);
if (!end_reached) {
// fill buffer
while (buffer_end < BUFFER_SIZE - 1) {
char c = getchar();
if (!feof(stdin)) {
buffer[buffer_end++] = c;
} else {
end_reached = 1;
// EOF marker.
buffer[buffer_end++] = EOF_MARKER;
break;
}
}
buffer[buffer_end] = '\0';
}
while (1) {
char c = buffer[forward++];
switch(state) {
case 0: if (c == ' ' || c == '\t' || c == '\n') {
state = 0;
lexeme_beginning++;
} else {
switch(c) {
case ';': return SEMICOLON;
case ')': return CLOSE_BRACKET;
case '(': return OPEN_BRACKET;
case '=': return EQUALS;
case EOF_MARKER: return EOF;
default: if (isalpha(c)) { state = 1; }
else if (isdigit(c)) { state = 2; }
else { lex_error(); }
break;
}
} break;
case 1: if (isdigit(c) || isalpha(c)) {
state = 1;
} else {
// retract forward pointer.
forward--;
int n = forward - lexeme_beginning;
strncpy(token_value_str, buffer+lexeme_beginning, n);
token_value_str[n] = '\0';
symtable_record_ptr rec = symtable_get(token_value_str);
if (rec) {
return rec->token;
} else {
return ID;
}
} break;
case 2: if (isdigit(c)) {
state = 2;
} else {
// retract forward pointer.
forward--;
int n = forward - lexeme_beginning;
strncpy(token_value_str, buffer+lexeme_beginning, n);
token_value_str[n] = '\0';
token_value = atoi(token_value_str);
return NUM;
} break;
default: lex_error();
}
}
}
