void differ(string what, Attributes a1, Attributes a2)
{
System.Console.WriteLine("{0} {1} << {2} >> {3} {4}",
a1.loc.PathPoint(),
Enum.GetName(a1.token.GetType(), a1.token),
what,
a2.loc.PathPoint(),
Enum.GetName(a2.token.GetType(), a2.token));
}
void next()
{
m_attrib = m_scanner.scan();
if (m_loc != null) m_loc.copy(m_attrib.loc);
}
public Attributes interpret(Attributes attrib)
{
if (Token.STRING == attrib.token) {
StringBuilder sb = new StringBuilder();
int i = 1;
while (i < attrib.literal.Length-1) {
if ('\\' == attrib.literal[i]) {
if ('"' == attrib.literal[i+1] || '\\' == attrib.literal[i+1]) {
i++;
}
}
sb.Append(attrib.literal[i]);
i++;
}
attrib.value = sb.ToString();
} else if (Token.BOOL == attrib.token) {
if ("#t" == attrib.literal) {
attrib.value = true;
} else {
attrib.value = false;
}
} else if (Token.CHAR == attrib.token) {
string value = attrib.literal.Substring(2);
if (1 == value.Length) {
attrib.value = value[0];
} else {
if (value.Equals("space", StringComparison.OrdinalIgnoreCase)) {
attrib.value = ' ';
} else if (value.Equals("newline", StringComparison.OrdinalIgnoreCase)) {
attrib.value = '\n';
} else {
throw lexical_error("invalid named character");
}
}
} else if (Token.NUM == attrib.token) {
if (!Number.parse_number(attrib.literal, out attrib.value)) {
throw lexical_error(String.Format("invalid number literal '{0}'", attrib.literal));
}
} else if (Token.NAMED_CONSTANT == attrib.token) {
if ("#!optional" == attrib.literal) {
attrib.value = "optional";
} else if ("#!rest" == attrib.literal) {
attrib.value = "rest";
} else {
throw lexical_error("invalid named constant");
}
} else if (Token.BIT_STRING == attrib.token) {
throw lexical_error("bit strings not implemented");
} else if (Token.HASH_NUMBER == attrib.token) {
throw lexical_error("hash numbers not implemented");
} else if (Token.ID == attrib.token) {
object value;
if (attrib.literal == ".") {
attrib.value = attrib.literal;
attrib.token = Token.DOT;
} else if (Number.parse_number(attrib.literal, out value)) {
attrib.value = value;
attrib.token = Token.NUM;
} else {
attrib.value = Symbol.get_symbol(attrib.literal);
}
} else {
attrib.value = attrib.literal;
}
return attrib;
}
public Attributes read()
{
next();
Attributes attrib = new Attributes();
attrib.loc = m_reader.loc.clone();
while (';' == cin || ('#' == cin && '|' == peek) || is_whitespace(cin)) {
line_comment();
if (!nested_comment()) {
throw lexical_error("<eof> in comment");
}
if (is_whitespace(cin)) {
next();
}
}
attrib.loc.copy(m_reader.loc);
if ('\0' == cin) {
attrib.token = Token.EOF;
} else if ('(' == cin) {
attrib.literal = "(";
attrib.token = Token.OPEN_PAREN;
} else if (')' == cin) {
attrib.literal = ")";
attrib.token = Token.CLOSE_PAREN;
} else if ('\'' == cin) {
attrib.literal = "'";
attrib.token = Token.QUOTE;
} else if ('`' == cin) {
attrib.literal = "`";
attrib.token = Token.BACKQUOTE;
} else if ('"' == cin) {
StringBuilder sb = new StringBuilder();
sb.Append(cin);
while (peek != '"') {
if ('\0' == cin) throw lexical_error("<eof> in string literal");
if ('\\' == peek) {
next();
sb.Append(cin);
}
next();
sb.Append(cin);
}
next();
sb.Append(cin);
attrib.literal = sb.ToString();
attrib.token = Token.STRING;
} else if ('#' == cin) {
StringBuilder sb = new StringBuilder();
sb.Append(cin);
if ('t' == peek || 'f' == peek) {
next();
sb.Append(cin);
attrib.token = Token.BOOL;
} else if ('\\' == peek) {
next();
sb.Append(cin);
if (is_letter(peek)) {
slurp(sb);
} else {
next();
sb.Append(cin);
}
attrib.token = Token.CHAR;
} else if ('(' == peek) {
next();
sb.Append(cin);
attrib.token = Token.VECTOR;
} else if (
'b' == peek || 'B' == peek ||
'e' == peek || 'E' == peek ||
'i' == peek || 'I' == peek ||
'd' == peek || 'D' == peek ||
'o' == peek || 'O' == peek ||
'x' == peek || 'X' == peek) {
slurp(sb);
attrib.token = Token.NUM;
} else if ('!' == peek) {
slurp(sb);
attrib.token = Token.NAMED_CONSTANT;
} else if ('*' == peek) {
slurp(sb);
attrib.token = Token.BIT_STRING;
} else if ('[' == peek) {
next();
sb.Append(cin);
attrib.token = Token.EXTERNAL;
} else if ('@' == peek) {
slurp(sb);
attrib.token = Token.HASH_NUMBER;
} else if ('=' == peek) {
next();
sb.Append(cin);
attrib.token = Token.CIRCULAR_INPUT;
} else if ('#' == peek) {
next();
sb.Append(cin);
attrib.token = Token.CIRCULAR_OUTPUT;
} else {
throw lexical_error("invalid # sequence");
}
attrib.literal = sb.ToString();
} else if (',' == cin) {
if ('@' == peek) {
next();
attrib.literal = ",@";
attrib.token = Token.SPLICE;
} else {
attrib.literal = ",";
attrib.token = Token.COMMA;
}
} else if (']' == cin) {
attrib.literal = "]";
attrib.token = Token.CLOSE_SQUARE;
} else if (
'|' == cin ||
'[' == cin ||
'{' == cin ||
'}' == cin) {
attrib.literal = char.ToString(cin);
throw lexical_error("reserved token");
} else {
StringBuilder sb = new StringBuilder();
sb.Append(cin);
slurp(sb);
attrib.literal = sb.ToString();
attrib.token = Token.ID;
}
return attrib;
}