/// <summary> [PM] 4.1.3 Traverse the term and verify that no null arguments remain
/// (for assertions).
/// </summary>
static bool validTerm(PBTerm pbTerm)
{
if (pbTerm == null)
{
return(false);
}
// FIXME: Traverse all args[] arrays (without running out of Java
// stack!)
return(true);
}
/*
* bump the term onto the stack and then push terms on the resulting
* stack. Never null.
*/
public Work bump(PBTerm term, PBTerm[] terms)
{
// Note that bump(term) may return null. This is why we do not use
// something like bump(term).push(terms).
Work tmp = new Work(terms, bump(term));
if (FastParser.logging)
{
Console.Out.WriteLine("bump() returning new: " + tmp);
}
return(tmp);
}
internal virtual void fastWrite(FastWriter writer)
{
foreach (string key in bindings.Keys)
{
PBTerm value = (PBTerm)bindings [key];
writer.writeList();
writer.writeCompound("=", 2);
// Arg 1
writer.writeAtom(key);
// Arg 2
writer.writeTerm(value);
}
writer.writeNIL();
}
public override string ToString()
{
System.Text.StringBuilder sb = new System.Text.StringBuilder().Append('[');
sb.Append(arguments [0].ToString());
PBTerm t = arguments [1];
while (!t.EmptyList)
{
sb.Append(',');
sb.Append(t.head().ToString());
t = t.tail();
}
sb.Append(']');
return(sb.ToString());
}
/// <summary> For debugging.
/// </summary>
public override string ToString()
{
System.Text.StringBuilder buffer = new System.Text.StringBuilder();
buffer.Append('[');
string prefix = "";
foreach (string key in bindings.Keys)
{
buffer.Append(prefix);
prefix = ",";
PBTerm value = (PBTerm)bindings [key];
buffer.Append(key).Append('=').Append(value.toPrologString());
}
buffer.Append(']');
return(buffer.ToString());
}
// [PD] 4.0.0 Non-recursive version
System.Text.StringBuilder getString(System.Text.StringBuilder sbuf)
{
PBListCell pbt = this;
PBTerm h;
do
{
h = pbt.arguments [0];
if (h.Atom && h.Name.Length == 1)
{
// Is head a one char
// atom?
sbuf.Append(h.Name);
}
else if (h.Integer)
{
// Is head an integer?
// *** FIXME: Perhaps check if this cast truncates.
int c = (int)h.intValue();
if (!isUnicode(c))
{
throw new InvalidOperationException("not a list of characters");
}
appendCodePoint(sbuf, c);
}
else
{
throw new InvalidOperationException("not a list of characters");
}
PBTerm t = pbt.arguments [1]; // tail()
if (t == PBTerm.NIL)
{
return(sbuf);
}
else
{
if (t.ListCell)
{
pbt = (PBListCell)t;
}
else
{
throw new InvalidOperationException("not a list of characters");
}
}
} while (true);
}
/// <summary> Creates a new {@link se.sics.prologbeans.PBTerm} instance representing a
/// list with the characters, as integer values, in the string argument as
/// its elements.
/// </summary>
/// <param name="value">the non-null value to represent
/// </param>
/// <returns> a term representing the argument
/// </returns>
static public PBTerm makeTerm(string value)
{
if (value == null)
{
throw new ArgumentNullException("value");
}
// [PM] 4.3.2
{
PBTerm tail = PBTerm.NIL;
for (int i = value.Length - 1; i >= 0; i--)
{
tail = PBTerm.makeTerm(PBTerm.makeTerm(value [i]), tail);
}
return(tail);
}
}
/// <summary> Update top of stack. Return the resulting stack, i.e. either 'this'
/// or this.next.
/// </summary>
internal Work bump(PBTerm term)
{
// assert i < args.length;
// assert term != null;
args [i] = term;
i++;
if (i < args.Length)
{
if (FastParser.logging)
{
Console.Out.WriteLine("bump() returning this: " + this);
}
return(this);
}
if (FastParser.logging)
{
Console.Out.WriteLine("bump() returning next: " + next);
}
return(next);
}
internal virtual void writeTerm(PBTerm term)
{
WriteWork stack = new WriteWork(new [] { term }, null);
do
{
PBTerm t = stack.bump();
if (t != null)
{
PBTerm[] args = t.fastWritePrefix(this);
if (args.Length > 0)
{
stack = stack.push(args);
}
}
else
{
// top-most entry exhausted, pop it.
stack = stack.prune();
}
} while (stack != null);
}
/// <summary> Adds the specified variable binding. The variable name must start
/// with an upper case letter or '_'.
/// </summary>
/// <param name="name">a prolog variable name
/// </param>
/// <param name="value">the value to bind to the variable
/// </param>
/// <returns> a reference to this <c>Bindings</c> object
/// </returns>
/// <exception cref="System.ArgumentException"> if the name is not a
/// valid prolog variable name
/// </exception>
public virtual Bindings bind(string name, float value)
{
return(bind(name, PBTerm.makeTerm(value)));
}
/// <summary> Adds the specified variable binding. The variable name must start
/// with an upper case letter or '_'. The value will be bound as an
/// atom.
/// </summary>
/// <param name="name">a prolog variable name
/// </param>
/// <param name="value">the value to bind to the variable as an atom
/// </param>
/// <returns> a reference to this <c>Bindings</c> object
/// </returns>
/// <exception cref="System.ArgumentException"> if the name is not a
/// valid prolog variable name
/// </exception>
public virtual Bindings bindAtom(string name, string value)
{
return(bind(name, PBTerm.makeAtom(value)));
}
/// <summary> Adds the specified variable binding. The variable name must start
/// with an upper case letter or '_'.
/// </summary>
/// <param name="name">a prolog variable name
/// </param>
/// <param name="value">the value to bind to the variable
/// </param>
/// <returns> a reference to this <c>Bindings</c> object
/// </returns>
/// <exception cref="System.ArgumentException"> if the name is not a
/// valid prolog variable name
/// </exception>
public virtual Bindings bind(string name, PBTerm value)
{
checkVar(name);
bindings [name] = value;
return(this);
}
/*
* [PM] 4.1.3 Manage an explicit stack to avoid running out of Java stack
* (SPRM 11909)
*/
PBTerm parseTerm(System.IO.Stream stream)
{
Work outer = new Work(new PBTerm[1], null);
Work stack = outer;
do
{
int chr = stream.ReadByte();
PBTerm term;
if (FastParser.logging)
{
Console.Out.WriteLine("parseTerm() switch on " + chr);
}
switch (chr)
{
case INTEGER:
{
string val = getString(stream);
// return new PBInteger(val);
try {
term = new PBInteger(Convert.ToInt64(val, 10), val);
} catch (FormatException /* nfe */) {
// FIXME: Perhaps not catch FormatException? If malformed then it is no bignum either.
term = new PBBignum(BigInteger.Parse(val), val);
} catch (OverflowException) {
term = new PBBignum(BigInteger.Parse(val), val);
}
if (logging)
{
Console.Out.WriteLine("bump() INTEGER " + val);
}
stack = stack.bump(term);
}
break;
case FLOAT:
{
string val = getString(stream);
term = new PBFloat(Double.Parse(val), val);
if (logging)
{
Console.Out.WriteLine("bump() FLOAT " + val);
}
stack = stack.bump(term);
}
break;
case ATOM:
{
string val = getString(stream);
term = PBTerm.makeAtom(val);
if (logging)
{
Console.Out.WriteLine("bump() ATOM " + val);
}
stack = stack.bump(term);
}
break;
case VARIABLE:
{
string val = '_' + getString(stream);
if (variableTable == null)
{
variableTable = System.Collections.Hashtable.Synchronized(new System.Collections.Hashtable());
}
PBVariable var = (PBVariable)variableTable [val];
if (var == null)
{
var = new PBVariable(val);
variableTable [val] = var;
}
term = var;
if (logging)
{
Console.Out.WriteLine("bump() VARIABLE " + val);
}
stack = stack.bump(term);
}
break;
case STRING:
{
byte[] val = getBytes(stream);
PBTerm t = parseTerm(stream);
// Note that this builds the list from the end.
for (int i = val.Length - 1; i >= 0; i--)
{
t = PBTerm.makeTerm(new PBInteger(val [i]), t);
}
term = t;
if (logging)
{
Console.Out.WriteLine("bump() STRING " + val);
}
stack = stack.bump(term);
}
break;
case LIST:
{
const int noTerms = 2;
PBTerm[] terms = new PBTerm[noTerms];
term = new PBListCell(terms);
if (logging)
{
Console.Out.WriteLine("bump() LIST ./2");
}
stack = stack.bump(term, terms);
}
break;
case NIL:
{
term = PBTerm.NIL;
if (logging)
{
Console.Out.WriteLine("bump() NIL");
}
stack = stack.bump(term);
}
break;
case COMPOUND:
{
string val = getString(stream);
int noTerms = stream.ReadByte();
PBTerm[] terms = new PBTerm[noTerms];
term = PBTerm.makeTerm(val, terms);
if (logging)
{
Console.Out.WriteLine("bump() COMPOUND " + val + "/" + noTerms);
}
stack = stack.bump(term, terms);
}
break;
default:
throw new System.IO.IOException("Parse error: illegal character " + (char)chr);
}
} while (stack != null);
// assert outer != null;
// assert outer.args != null && outer.args.length == 1;
// assert validTerm(outer.args[0]);
if (logging)
{
Console.Out.WriteLine("parseTermWithStack returning " + outer.args [0]);
}
return(outer.args [0]);
}
/// <summary> Creates a new {@link se.sics.prologbeans.PBTerm} instance representing a
/// list cell.
/// </summary>
/// <param name="head">the first argument of the list cell
/// </param>
/// <param name="tail">the second argument of the list cell
/// </param>
/// <returns> a term representing the argument
/// </returns>
static public PBTerm makeTerm(PBTerm head, PBTerm tail)
{
return(new PBListCell(head, tail));
}
internal PBListCell(PBTerm head, PBTerm tail) : this(new [] { head, tail })
{
}