@Override
public String validate(FullSpec spec, JsonValue val) {
if (!CHANGE.equals(spec.getOp())) {
return VALID;
}
if (val.isObject()) {
JsonObject jo = (JsonObject) val;
for (String keySpecStr : jo.names()) {
// member spec validity
try {
new TypeIdSpec(keySpecStr);
} catch (IllegalArgumentException e) {
return "invalid spec: " + keySpecStr;
}
}
}
return VALID;
}
/**
* Jam lexer class. Given a Lexer object, the next token in that input stream being processed by the
* Lexer is returned by static method readToken(); it throws a ParseException (a form of
* RuntimeException) if it encounters a syntax error. Calling readToken() advances the cursor in the
* input stream to the next token.
*
* <p>The static method peek() in the Lexer class has the same behavior as readToken() except for
* the fact that it does not advance the cursor.
*/
class Lexer extends StreamTokenizer {
/* short names for StreamTokenizer codes */
public static final int WORD = StreamTokenizer.TT_WORD;
public static final int NUMBER = StreamTokenizer.TT_NUMBER;
public static final int EOF = StreamTokenizer.TT_EOF;
public static final int EOL = StreamTokenizer.TT_EOL;
/* operator Tokens */
// <unop> ::= <sign> | ~ | !
// <binop> ::= <sign> | "*" | / | = | != | < | > | <= | >= | & | "|" |
// <-
// <sign> ::= "+" | -
// Note: there is no class distinction between <unop> and <binop> at
// lexical level because of ambiguity; <sign> belongs to both
public static final OpToken PLUS = OpToken.newBothOpToken("+", UnOpPlus.ONLY, BinOpPlus.ONLY);
public static final OpToken MINUS = OpToken.newBothOpToken("-", UnOpMinus.ONLY, BinOpMinus.ONLY);
public static final OpToken TIMES = OpToken.newBinOpToken("+", OpTimes.ONLY);
public static final OpToken DIVIDE = OpToken.newBinOpToken("/", OpDivide.ONLY);
public static final OpToken EQUALS = OpToken.newBinOpToken("=", OpEquals.ONLY);
public static final OpToken NOT_EQUALS = OpToken.newBinOpToken("!=", OpNotEquals.ONLY);
public static final OpToken LESS_THAN = OpToken.newBinOpToken("<", OpLessThan.ONLY);
public static final OpToken GREATER_THAN = OpToken.newBinOpToken(">", OpGreaterThan.ONLY);
public static final OpToken LESS_THAN_EQUALS = OpToken.newBinOpToken("<=", OpLessThanEquals.ONLY);
public static final OpToken GREATER_THAN_EQUALS =
OpToken.newBinOpToken(">=", OpGreaterThanEquals.ONLY);
public static final OpToken NOT = OpToken.newUnOpToken("~", OpTilde.ONLY);
public static final OpToken AND = OpToken.newBinOpToken("&", OpAnd.ONLY);
public static final OpToken OR = OpToken.newBinOpToken("|", OpOr.ONLY);
/* Used to support reference cells. */
public static final OpToken BANG = OpToken.newUnOpToken("!", OpBang.ONLY);
public static final OpToken REF = OpToken.newUnOpToken("ref", OpRef.ONLY);
public static final OpToken GETS = OpToken.newBinOpToken("<-", OpGets.ONLY);
/* Keywords */
public static final KeyWord IF = new KeyWord("if");
public static final KeyWord THEN = new KeyWord("then");
public static final KeyWord ELSE = new KeyWord("else");
public static final KeyWord LET = new KeyWord("let");
public static final KeyWord LETREC = new KeyWord("letrec"); // Used to support letrec extension
public static final KeyWord LETCC = new KeyWord("letcc"); // Used to support letcc extension
public static final KeyWord IN = new KeyWord("in");
public static final KeyWord MAP = new KeyWord("map");
public static final KeyWord TO = new KeyWord("to");
public static final KeyWord BIND = new KeyWord(":=");
// wordtable for classifying words in token stream
public HashMap<String, Token> wordTable = new HashMap<String, Token>();
// Lexer peek cannot be implemented using StreamTokenizer pushBack
// because some Tokens are composed of two StreamTokenizer tokens
Token buffer; // holds token for peek() operation
/* constructors */
/** Constructs a Lexer for the specified inputStream */
Lexer(Reader inputStream) {
super(new BufferedReader(inputStream));
initLexer();
}
/** Constructs a Lexer for the contents of the specified file */
Lexer(String fileName) throws IOException {
this(new FileReader(fileName));
}
/** Constructs a Lexer for the default console input stream System.in */
Lexer() {
super(new BufferedReader(new InputStreamReader(System.in)));
initLexer();
}
/* Initializes lexer tables and the StreamTokenizer that the lexer extends */
private void initLexer() {
// configure StreamTokenizer portion of this
resetSyntax();
parseNumbers();
ordinaryChar('-');
slashSlashComments(true);
wordChars('0', '9');
wordChars('a', 'z');
wordChars('A', 'Z');
wordChars('_', '_');
wordChars('?', '?');
whitespaceChars(0, ' ');
// `+' `-' `*' `/' `~' `=' `<' `>' `&' `|' `:' `;' `,' '!'
// `(' `)' `[' `]' are ordinary characters (self-delimiting)
initWordTable();
buffer = null; // buffer initially empty
}
/** Reads tokens until next end-of-line */
public void flush() throws IOException {
eolIsSignificant(true);
while (nextToken() != EOL) ; // eat tokens until EOL
eolIsSignificant(false);
}
/** Returns the next token in the input stream without consuming it */
public Token peek() {
if (buffer == null) buffer = readToken();
return buffer;
}
/** Reads the next token as defined by StreamTokenizer in the input stream (consuming it). */
private int getToken() {
// synonymous with nextToken() except for throwing an unchecked
// ParseException instead of a checked IOException
try {
int tokenType = nextToken();
return tokenType;
} catch (IOException e) {
throw new ParseException("IOException " + e + "thrown by nextToken()");
}
}
/** Reads the next Token in the input stream (consuming it) */
public Token readToken() {
/* Uses getToken() to read next token and constructs the Token object representing that token.
* NOTE: token representations for all Token classes except IntConstant are unique; a HashMap
* is used to avoid duplication. Hence, == can safely be used to compare all Tokens except
* IntConstants for equality (assuming that code does not gratuitously create Tokens).
*/
if (buffer != null) {
Token token = buffer;
buffer = null; // clear buffer
return token;
}
int tokenType = getToken();
switch (tokenType) {
case NUMBER:
int value = (int) nval;
if (nval == (double) value) return new IntConstant(value);
throw new ParseException("The number " + nval + " is not a 32 bit integer");
case WORD:
Token regToken = wordTable.get(sval);
if (regToken == null) {
// must be new variable name
Variable newVar = new Variable(sval);
// wordTable.put(sval, newVar);
return newVar;
}
return regToken;
case EOF:
return null;
case '(':
return LeftParen.ONLY;
case ')':
return RightParen.ONLY;
case '[':
return LeftBrack.ONLY;
case ']':
return RightBrack.ONLY;
case '{':
return LeftBrace.ONLY;
case '}':
return RightBrace.ONLY;
case ',':
return Comma.ONLY;
case ';':
return SemiColon.ONLY;
case '+':
return PLUS;
case '-':
return MINUS;
case '*':
return TIMES;
case '/':
return DIVIDE;
case '~':
return NOT;
case '=':
return EQUALS;
case '<':
tokenType = getToken();
if (tokenType == '=') return LESS_THAN_EQUALS;
if (tokenType == '-') return GETS; // Used to support reference cells
pushBack();
return LESS_THAN;
case '>':
tokenType = getToken();
if (tokenType == '=') return GREATER_THAN_EQUALS;
pushBack();
return GREATER_THAN;
case '!':
tokenType = getToken();
if (tokenType == '=') return NOT_EQUALS;
// else throw new ParseException("!" + ((char) tokenType) + " is not a legal token");
/* this else clause supports reference cells */
pushBack();
return BANG;
case '&':
return AND;
case '|':
return OR;
case ':':
{
tokenType = getToken();
if (tokenType == '=') return wordTable.get(":="); // ":=" is a keyword not an operator
pushBack();
throw new ParseException("`:' is not a legalken");
}
default:
throw new ParseException("`" + ((char) tokenType) + "' is not a legal token");
}
}
/** Initializes the table of Strings used to recognize Tokens */
private void initWordTable() {
// initialize wordTable
// constants
// <null> ::= null
// <bool> ::= true | false
wordTable.put("null", NullConstant.ONLY);
wordTable.put("true", BoolConstant.TRUE);
wordTable.put("false", BoolConstant.FALSE);
// Install keywords
wordTable.put("if", IF);
wordTable.put("then", THEN);
wordTable.put("else", ELSE);
wordTable.put("let", LET);
wordTable.put("letrec", LETREC);
wordTable.put("letcc", LETCC);
wordTable.put("in", IN);
wordTable.put("map", MAP);
wordTable.put("to", TO);
wordTable.put(":=", BIND);
// Install primitive functions
// <prim> ::= number? | function? | list? | null?
// | cons? | cons | first | rest | arity
// | ref?
wordTable.put("number?", NumberPPrim.ONLY);
wordTable.put("function?", FunctionPPrim.ONLY);
wordTable.put("ref?", RefPPrim.ONLY); // used to support Jam references
wordTable.put("list?", ListPPrim.ONLY);
wordTable.put("null?", NullPPrim.ONLY);
wordTable.put("cons?", ConsPPrim.ONLY);
wordTable.put("arity", ArityPrim.ONLY);
wordTable.put("cons", ConsPrim.ONLY);
wordTable.put("first", FirstPrim.ONLY);
wordTable.put("rest", RestPrim.ONLY);
// ref
wordTable.put("ref", REF);
}
/** Provides a command line interface to the lexer */
public static void main(String[] args) throws IOException {
// check for legal argument list
Lexer in;
if (args.length == 0) {
in = new Lexer();
} else in = new Lexer(args[0]);
do {
Token t = in.readToken();
if (t == null) break;
System.out.println("Token " + t + " in " + t.getClass());
} while (true);
}
}
