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# Class w3c.tools.sexpr.SimpleSExprStream

    java.lang.Object
       |
       +----java.io.InputStream
               |
               +----java.io.FilterInputStream
                       |
                       +----java.io.PushbackInputStream
                               |
                               +----w3c.tools.sexpr.SimpleSExprStream

public class SimpleSExprStream
extends PushbackInputStream
implements SExprStream

Basic implementation of the SExprStream parser interface.

##

SimpleSExprStream(InputStream)
  Initializes the parser with no read table and no symbol table assigned.

##

addParser(char, SExprParser)
  Associates a dispatch character with a parser in the read table.
getListsAsVectors()
  Checks whether lists should be parsed as Vectors or Cons cells.
getReadtable()
  Accesses the read table of the parser.
getScratchBuffer()
  Accesses an empty string buffer available temporary storage.
getSymbols()
  Accesses the symbol table of the parser.
isAtomChar(char, boolean)
  Predicate function for checking if a chahracter can belong to an atom.
main(String[])
makeNumber(String)
  Attempts to parse a number from the string.
parse()
  Parses a single object from the underlying input stream.
parse(char, SExprStream)
  Parses a single object started by the character c.
parseAtom(char)
  Parses an atom (a number or a symbol).
parseList()
  Parses a list (as Cons cells) sans first character.
parseString()
  Parses a double-quote -delimited string (sans the first character).
parseVector(Vector, char)
  Parses a list (as a Vector) sans first character.
prettyPrint(Object)
  Produces a normative form of the string representation of an s-expression.
printExpr(Object, PrintStream)
  Produces a printed representation of an s-expression.
readSkipWhite()
  Reads from the stream, skipping whitespace and comments.
setListsAsVectors(boolean)
  Controls whether lists are represented as Vectors or Cons cells.
setReadtable(Readtable)
  Assigns a new read table to the parser.
setSymbols(Dictionary)
  Assigns a symbol table to the parser.
toNormativeForm(Object)
  Produces a normative form of the string representation of an s-expression.
toString(Object)
  Produces a string representation of an s-expression.

##

SimpleSExprStream

     public SimpleSExprStream(InputStream input)

  Initializes the parser with no read table and no symbol table assigned. Parsed lists will be represented as Cons cells.

##

getSymbols

     public Dictionary getSymbols()

  Accesses the symbol table of the parser. If no symbol table has been assigned, creates an empty table.

setSymbols

     public Dictionary setSymbols(Dictionary symbols)

  Assigns a symbol table to the parser. Assigning `null` will prevent an empty symbol table to be created in the future.

getReadtable

     public Readtable getReadtable()

  Accesses the read table of the parser. If no read table has been assigned, creates an empty table.

setReadtable

     public Readtable setReadtable(Readtable readtable)

  Assigns a new read table to the parser.

getListsAsVectors

     public boolean getListsAsVectors()

  Checks whether lists should be parsed as Vectors or Cons cells.

setListsAsVectors

     public boolean setListsAsVectors(boolean listsAsVectors)

  Controls whether lists are represented as Vectors or Cons cells.

getScratchBuffer

     public StringBuffer getScratchBuffer()

  Accesses an empty string buffer available temporary storage. This buffer can be used by sub-parsers as a scratch area. Please note that the buffer is not guarded in any way, so multithreaded and reentrant programs must worry about this themselves.

parse

     public Object parse() throws SExprParserException, IOException

  Parses a single object from the underlying input stream.

  Throws: SExprParserException
    if syntax error was detected
  Throws: IOException
    if any other I/O-related problem occurred

parse

     public Object parse(char c,
                         SExprStream stream) throws SExprParserException, IOException

  Parses a single object started by the character c. Implements the SExprParser interface.

  Throws: SExprParserException
    if syntax error was detected
  Throws: IOException
    if any other I/O-related problem occurred

parseList

     protected Cons parseList() throws SExprParserException, IOException

  Parses a list (as Cons cells) sans first character.

  Throws: SExprParserException
    if syntax error was detected
  Throws: IOException
    if any other I/O-related problem occurred

parseVector

     protected Vector parseVector(Vector vector,
                                  char delimiter) throws SExprParserException, IOException

  Parses a list (as a Vector) sans first character. In order to parse list-like structures delimited by other characters than parentheses, the delimiting (ending) character has to be provided.

  Throws: SExprParserException
    if syntax error was detected
  Throws: IOException
    if any other I/O-related problem occurred

parseAtom

     protected Object parseAtom(char c) throws SExprParserException, IOException

  Parses an atom (a number or a symbol). Since anything that is not a number is a symbol, syntax errors are not possible.

  Throws: SExprParserException
    not signalled but useful for the protocol
  Throws: IOException
    if an I/O problem occurred (e.g. end of file)

parseString

     public String parseString() throws SExprParserException, IOException

  Parses a double-quote -delimited string (sans the first character). Please note: no escape-character interpretation is performed. Override this method for any escape character handling.

  Throws: SExprParserException
    not signalled but useful for the protocol
  Throws: IOException
    any I/O problem (including end of file)

isAtomChar

     protected boolean isAtomChar(char c,
                                  boolean first)

  Predicate function for checking if a chahracter can belong to an atom.

  Parameters:
    first - if true means that c is the first character of the atom

readSkipWhite

     public char readSkipWhite() throws IOException

  Reads from the stream, skipping whitespace and comments.

  Throws: IOException
    if an I/O problem occurred (including end of file)

makeNumber

     protected Number makeNumber(String s) throws NumberFormatException

  Attempts to parse a number from the string.

  Throws: NumberFormatException
    the string does not represent a number

addParser

     public SExprParser addParser(char key,
                                  SExprParser parser)

  Associates a dispatch character with a parser in the read table.

printExpr

     public static void printExpr(Object expr,
                                  PrintStream out)

  Produces a printed representation of an s-expression.

toString

     public static String toString(Object expr)

  Produces a string representation of an s-expression.

toNormativeForm

     public String toNormativeForm(Object v)

  Produces a normative form of the string representation of an s-expression.

prettyPrint

     public String prettyPrint(Object v)

  Produces a normative form of the string representation of an s-expression.

main

     public static void main(String args[]) throws SExprParserException, IOException

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