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namespace Eva {
public static Term? parse(string str, ...) {
va_list va = va_list();
string s = str.chomp();
if(s.length == 0)
return null;
Term? ret = parse_term(ref s, ref va);
if(s.length != 0)
return null;
else
return ret;
}
private static Term? parse_term(ref string str, ref va_list va) {
str = str.chug();
unichar c = str.get_char();
if(c.isdigit() || c == '-') {
return parse_number(ref str);
}
else if(c.islower() || c == '\'') {
return parse_atom(ref str);
}
else if(c == '"') {
return parse_string(ref str);
}
else if(c.isupper() || c == '_') {
return parse_var(ref str);
}
else if(c == '<') {
return parse_binary(ref str);
}
else if(c == '{') {
return parse_tuple(ref str, ref va);
}
else if(c == '[') {
return parse_list(ref str, ref va);
}
else if(c == '~') {
return get_va(ref str, ref va);
}
else {
return null;
}
}
private static Term? parse_number(ref string str) {
bool positive = true;
bool fractional = false;
unowned string s = str;
if(s.get_char() == '-') {
positive = false;
s = s.next_char();
if(s.length == 0 || !s.get_char().isdigit())
return null;
}
if(s.get_char() == '.')
return null;
while(s.length > 0) {
unichar c = s.get_char();
if(c == '.') {
if(fractional)
return null;
fractional = true;
s = s.next_char();
if(s.length == 0 || !s.get_char().isdigit())
return null;
continue;
}
if(!c.isdigit())
break;
s = s.next_char();
}
string number = str.substring(0, str.pointer_to_offset(s));
str = s;
if(fractional) {
return new Double(number.to_double());
}
else if(positive) {
return new UInt(number.to_ulong());
}
else {
return new Int(number.to_long());
}
}
private static Term? parse_atom(ref string str) {
if(str.get_char() == '\'') {
string atom = "";
unowned string s = str.next_char();
while(s.length > 0) {
unichar c = s.get_char();
if(c == '\'')
break;
if(c == '\\') {
s = s.next_char();
if(s.length == 0)
return null;
c = s.get_char();
}
if(c > 255) {
return null;
}
string buf = string.nfill(6, 0);
c.to_utf8(buf);
atom += buf;
s = s.next_char();
}
if(s.length == 0)
return null;
Term ret = new Atom(atom);
str = s.next_char();
return ret;
}
else {
unowned string s = str;
while(s.length > 0) {
unichar c = s.get_char();
if(c != '_' && !c.isalnum()) {
break;
}
s = s.next_char();
}
Term ret = new Atom(str.substring(0, str.pointer_to_offset(s)));
str = s;
return ret;
}
}
private static Term? parse_string(ref string str) {
string ret = do_parse_string(ref str);
if(ret == null)
return null;
return new String(ret);
}
private static string? do_parse_string(ref string str) {
if(str.get_char() != '"') {
return null;
}
string retstr = "";
unowned string s = str.next_char();
while(s.length > 0) {
unichar c = s.get_char();
if(c == '\"')
break;
if(c == '\\') {
s = s.next_char();
if(s.length == 0)
return null;
c = s.get_char();
}
string buf = string.nfill(6, 0);
c.to_utf8(buf);
retstr += buf;
s = s.next_char();
}
if(s.length == 0)
return null;
str = s.next_char();
return retstr;
}
private static Term? parse_var(ref string str) {
unowned string s = str;
while(s.length > 0) {
unichar c = s.get_char();
if(c != '_' && !c.isalnum()) {
break;
}
s = s.next_char();
}
Term ret = new Var(str.substring(0, str.pointer_to_offset(s)));
str = s;
return ret;
}
private static Term? parse_tuple(ref string str, ref va_list va) {
Gee.ArrayList<Term> list = new Gee.ArrayList<Term>();
if(str.get_char() != '{')
return null;
unowned string s = str.next_char();
while(s.length > 0 && s.get_char().isspace()) {
s = s.next_char();
}
if(s.length == 0)
return null;
if(s.get_char() == '}') {
str = s.next_char();
return new Tuple({});
}
while(s.length > 0) {
if(s.get_char().isspace()) {
s = s.next_char();
continue;
}
str = s;
Term t = parse_term(ref str, ref va);
if(t == null)
return null;
list.add(t);
s = str;
while(s.length > 0 && s.get_char().isspace()) {
s = s.next_char();
}
unichar c = s.get_char();
if(c == '}') {
str = s.next_char();
Term[] terms = list.to_array();
return new Tuple(terms);
}
else if(c != ',') {
return null;
}
else {
s = s.next_char();
}
}
return null;
}
private static Term? parse_list(ref string str, ref va_list va) {
if(str.get_char() != '[')
return null;
str = str.next_char();
return parse_list_tail(ref str, ref va);
}
private static Term? parse_list_tail(ref string str, ref va_list va) {
str = str.chug();
if(str.length == 0)
return null;
if(str.get_char() == ']') {
str = str.next_char();
return List.empty;
}
Term head = parse_term(ref str, ref va);
if(head == null)
return null;
str = str.chug();
if(str.length == 0)
return null;
unichar c = str.get_char();
str = str.next_char();
switch(c) {
case ']':
return new Cons(head);
case ',':
return new Cons(head, parse_list_tail(ref str, ref va));
case '|':
Term ret = new Cons(head, parse_term(ref str, ref va));
str = str.chug();
if(str.length == 0 || str.get_char() != ']')
return null;
str = str.next_char();
return ret;
default:
return null;
}
}
private static Term? parse_binary(ref string str) {
if(str.length < 4)
return null;
if(str[0:2] != "<<")
return null;
str = str.offset(2).chug();
if(str[0:2] == ">>") {
str = str.offset(2);
return new Binary({});
}
if(str.get_char() == '"') {
string ret = do_parse_string(ref str);
if(ret == null)
return null;
str = str.chug();
if(str.length < 2 || str[0:2] != ">>")
return null;
str = str.offset(2);
char[] binary = string_to_binary(ret);
return new Binary(binary);
}
else {
Gee.ArrayList<char> data = new Gee.ArrayList<char>();
while(str.length > 0) {
unichar c = str.get_char();
if(c != '-' && !c.isdigit())
return null;
unowned string beg = str;
unowned string end = str.next_char();
while(end.length > 0 && end.get_char().isdigit())
end = end.next_char();
data.add((char)beg.substring(0, beg.pointer_to_offset(end)).to_int());
str = end.chug();
if(str.length >= 2 && str[0:2] == ">>") {
str = str.offset(2);
// Workaround for libgee to_array bug 597737
char[] array = new char[data.size];
int index = 0;
foreach(char i in data) {
array[index++] = i;
}
return new Binary(array);
}
else if(str.length != 0 && str.get_char() == ',') {
str = str.next_char().chug();
}
else {
return null;
}
}
return null;
}
}
private static Term? get_va(ref string str, ref va_list va) {
if(str.get_char() != '~')
return null;
if(str.length < 2)
return null;
unichar c = str[1];
str = str.offset(2);
switch(c) {
case 'a':
return new Atom(va.arg<string>());
case 's':
return new String(va.arg<string>());
case 'i':
return new Int(va.arg<int>());
case 'l':
return new Int(va.arg<long>());
case 'u':
return new UInt(va.arg<ulong>());
case 'f':
case 'd':
return new Double(va.arg<double>());
case 'w':
return va.arg<Term>();
default:
return null;
}
}
}
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