*/
public class GrammarAST {
+ public static interface ImportResolver {
+ public InputStream getImportStream(String importname);
+ }
+
/**
* Returns a Union representing the metagrammar (<tt>meta.g</tt>); the Tree produced by
* parsing with this Union should be provided to <tt>buildFromAST</tt>
*/
public static Union getMetaGrammar() {
- return buildFromAST(MetaGrammar.meta, "s", new File[0]);
+ return buildFromAST(MetaGrammar.meta, "s", null);
}
/**
* @param s the name of the "start symbol"
* @param gbr a GrammarBindingResolver that resolves grammatical reductions into tree-node-heads
*/
- public static Union buildFromAST(Tree grammarAST, String startingNonterminal, File[] includes) {
- return new GrammarAST(includes, "").buildGrammar(grammarAST, startingNonterminal);
+ public static Union buildFromAST(Tree grammarAST, String startingNonterminal, ImportResolver resolver) {
+ return new GrammarAST(resolver, "").buildGrammar(grammarAST, startingNonterminal);
}
private static Object illegalTag = ""; // this is the tag that should never appear in the non-dropped output FIXME
// Instance //////////////////////////////////////////////////////////////////////////////
private final String prefix;
- private final File[] includes;
+ private final ImportResolver resolver;
- public GrammarAST(File[] includes, String prefix) {
+ public GrammarAST(ImportResolver resolver, String prefix) {
this.prefix = prefix;
- this.includes = includes;
+ this.resolver = resolver;
}
// Methods //////////////////////////////////////////////////////////////////////////////
}
if (head.equals("\"\"")) return "";
if (head.equals("\n")) return "\n";
+ if (head.equals("\t")) return "\t";
if (head.equals("\r")) return "\r";
- if (head.equals("SubGrammar")) return GrammarAST.buildFromAST(t.child(0), "s", includes);
+ if (head.equals("SubGrammar")) return GrammarAST.buildFromAST(t.child(0), "s", resolver);
if (head.equals("NonTerminal"))
return new NonTerminalNode(walkString(t.child(0)),
(Seq[][])walkChildren(t.child(1)), false, null, false);
return new NonTerminalNode(tag, seqs, false, null, false);
}
if (head.equals("#import")) {
- String fileName = (String)stringifyChildren(t.child(0));
- for(File f : includes) {
- File file = new File(f.getAbsolutePath()+File.separatorChar+fileName);
- if (!file.exists()) continue;
+ if (resolver != null) {
+ String fileName = (String)stringifyChildren(t.child(0));
try {
String newPrefix = t.size()<2 ? "" : (walkString(t.child(1))+".");
- FileInputStream fis = new FileInputStream(file);
+ InputStream fis = resolver.getImportStream(fileName);
+ if (fis==null)
+ throw new RuntimeException("unable to find #include file \""+fileName+"\"");
Tree tr = new CharParser(getMetaGrammar()).parse(fis).expand1();
- return (GrammarNode)new GrammarAST(includes, newPrefix).walk(tr);
+ return (GrammarNode)new GrammarAST(resolver, newPrefix).walk(tr);
} catch (Exception e) {
- throw new RuntimeException("while parsing " + file, e);
+ throw new RuntimeException("while parsing " + fileName, e);
}
+ } else {
+ throw new RuntimeException("no resolver given");
}
- throw new RuntimeException("unable to find #include file \""+fileName+"\"");
}
throw new RuntimeException("unknown head: \"" + head + "\" => " + (head.equals("...")));
}
/** a node in the AST which is resolved into an Element */
private abstract class ElementNode {
public boolean isLifted() { return false; }
- public boolean drop(Context cx) { return false; }
+ public boolean isDropped(Context cx) { return false; }
public Atom toAtom(Context cx) { throw new Error("can't convert a " + this.getClass().getName() + " to an atom: " + this); }
public abstract Element build(Context cx, NonTerminalNode cnt, boolean dropall);
}
+ /** a union, produced by a ( .. | .. | .. ) construct */
private class UnionNode extends ElementNode {
+
+ /** each component of a union is a sequence */
public Seq[][] sequences;
- public String sep = null;
+
+ /** if the union is a NonTerminal specified as Foo*=..., this is true */
public boolean rep;
+
+ /** if the union is a NonTerminal specified as Foo* /ws=..., then this is "ws" */
+ public String sep = null;
+
public UnionNode(Seq seq) { this(new Seq[][] { new Seq[] { seq } }); }
public UnionNode(Seq[][] sequences) { this(sequences, false, null); }
public UnionNode(Seq[][] sequences, boolean rep, String sep) {
this.rep = rep;
this.sep = sep;
}
- public boolean drop(Context cx) {
+ public boolean isDropped(Context cx) {
for(Seq[] seqs : sequences)
for(Seq seq : seqs)
- if (!seq.drop(cx))
+ if (!seq.isDropped(cx))
return false;
return true;
}
}
}
+ /** a NonTerminal is always a union at the top level */
private class NonTerminalNode extends UnionNode {
public boolean alwaysDrop;
public String name = null;
- public boolean drop(Context cx) { return alwaysDrop; }
+ public boolean isDropped(Context cx) { return alwaysDrop; }
public NonTerminalNode(String name, Seq[][] sequences, boolean rep, String sep, boolean alwaysDrop) {
super(sequences, rep, sep==null?null:(prefix + sep));
this.name = prefix + name;
public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return cx.get(name); }
}
+ /** a sequence */
private class Seq {
+ /** elements of the sequence */
+ ElementNode[] elements;
+ /** follow-set, if explicit */
+ ElementNode follow;
+ /** tag to add when building the AST */
+ String tag = null;
+ /** positive conjuncts */
+ HashSet<Seq> and = new HashSet<Seq>();
+ /** negative conjuncts */
+ HashSet<Seq> not = new HashSet<Seq>();
public boolean alwaysDrop = false;
- public boolean drop(Context cx) {
+ public boolean isDropped(Context cx) {
if (alwaysDrop) return true;
if (tag!=null) return false;
for(int i=0; i<elements.length; i++)
- if (!elements[i].drop(cx))
+ if (!elements[i].isDropped(cx) || ((elements[i] instanceof LiteralNode) && ((LiteralNode)elements[i]).caret))
return false;
return true;
}
- HashSet<Seq> and = new HashSet<Seq>();
- HashSet<Seq> not = new HashSet<Seq>();
- ElementNode[] elements;
- ElementNode follow;
- String tag = null;
public Seq(ElementNode e) { this(new ElementNode[] { e }); }
public Seq(ElementNode[] elements) { this(elements, true); }
public Seq(ElementNode[] el, boolean check) {
public Sequence build0(Context cx, NonTerminalNode cnt, boolean dropall) {
boolean[] drops = new boolean[elements.length];
Element[] els = new Element[elements.length];
- dropall |= drop(cx);
+ dropall |= isDropped(cx);
for(int i=0; i<elements.length; i++) {
if (dropall) drops[i] = true;
- else drops[i] = elements[i].drop(cx);
+ else drops[i] = elements[i].isDropped(cx);
if (elements[i] instanceof LiteralNode && ((LiteralNode)elements[i]).caret) {
if (tag != null) throw new RuntimeException("cannot have multiple tags in a sequence: " + this);
tag = ((LiteralNode)elements[i]).getLiteralTag();
}
}
+ /** reference to a NonTerminal by name */
private class ReferenceNode extends ElementNode {
public String nonTerminal;
public boolean parenthesized;
if (ret == null) throw new RuntimeException("unknown nonterminal \""+nonTerminal+"\"");
return ret.toAtom(cx);
}
- public boolean drop(Context cx) { return resolve(cx).drop(cx); }
+ public boolean isDropped(Context cx) { return resolve(cx).isDropped(cx); }
public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
Element ret = cx.get(nonTerminal);
if (ret == null) throw new RuntimeException("unknown nonterminal \""+nonTerminal+"\"");
}
}
+ /** a literal string */
private class LiteralNode extends ElementNode {
private String string;
private final String thePrefix = prefix;
}
public String getLiteralTag() { return caret ? thePrefix+string : null; }
public String toString() { return "\""+string+"\""; }
- public boolean drop(Context cx) { return true; }
+ public boolean isDropped(Context cx) { return true; }
public Atom toAtom(Context cx) {
if (string.length()!=1) return super.toAtom(cx);
Range.Set set = new Range.Set();
public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return CharAtom.string(string); }
}
+ /** an atom (usually a character class) */
private class AtomNode extends ElementNode {
char[][] ranges;
public AtomNode() { this(new char[0][]); }
}
}
+ /** a repetition */
private class RepeatNode extends ElementNode {
public ElementNode e, sep;
public final boolean zero, many, max;
this.e = e; this.sep = sep; this.zero = zero; this.many = many; this.max = max;
}
public Atom toAtom(Context cx) { return sep==null ? e.toAtom(cx) : super.toAtom(cx); }
- public boolean drop(Context cx) { return e.drop(cx); }
+ public boolean isDropped(Context cx) { return e.isDropped(cx); }
public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
Element ret = build(cx, cnt, dropall, illegalTag);
String must = "must be tagged unless they appear within a dropped expression or their contents are dropped: ";
- if (!dropall && !drop(cx) && !e.drop(cx))
+ if (!dropall && !isDropped(cx) && !e.isDropped(cx))
if (!many) throw new RuntimeException("options (?) " + must + ret);
else if (zero) throw new RuntimeException("zero-or-more repetitions (*) " + must + ret);
else throw new RuntimeException("one-or-more repetitions (+) " + must + ret);
}
}
+ /** helper class for syntactic constructs that wrap another construct */
private abstract class ElementNodeWrapper extends ElementNode {
protected ElementNode _e;
public ElementNodeWrapper(ElementNode e) { this._e = e; }
- public boolean drop(Context cx) { return _e.drop(cx); }
+ public boolean isDropped(Context cx) { return _e.isDropped(cx); }
public Atom toAtom(Context cx) { return _e.toAtom(cx); }
public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return _e.build(cx, cnt, dropall); }
}
+ /** a backtick node indicating that, when building the AST, the node's children should be inserted here */
private class BacktickNode extends ElementNodeWrapper {
public BacktickNode(ElementNode e) { super(e); }
public boolean isLifted() { return true; }
}
+ /** negation */
private class TildeNode extends ElementNodeWrapper {
public TildeNode(ElementNode e) { super(e); }
public Atom toAtom(Context cx) { return (Atom)((Topology<Character>)_e.toAtom(cx).complement()); }
private class DropNode extends ElementNodeWrapper {
public DropNode(ElementNode e) { super(e); }
- public boolean drop(Context cx) { return true; }
+ public boolean isDropped(Context cx) { return true; }
}
//////////////////////////////////////////////////////////////////////////////
} else {
ret = new Union(name, false);
map.put(name, ret);
- nt.buildIntoPreallocatedUnion(this, nt, nt.drop(this), ret);
+ nt.buildIntoPreallocatedUnion(this, nt, nt.isDropped(this), ret);
}
return ret;
}
projects / sbp.git / blobdiff