X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmeta%2FGrammarAST.java;h=e039b372c507da375ee3d425c8b20b9087429da7;hp=05c7b39dc7394dac4cc448b59f5a6dbc70f76422;hb=8fb8d27ebcaad8074b9d52b31d32406d522e5a57;hpb=013262fd96a3dfc4c2cd7a0ba320dd7981ce678c
diff --git a/src/edu/berkeley/sbp/meta/GrammarAST.java b/src/edu/berkeley/sbp/meta/GrammarAST.java
index 05c7b39..e039b37 100644
--- a/src/edu/berkeley/sbp/meta/GrammarAST.java
+++ b/src/edu/berkeley/sbp/meta/GrammarAST.java
@@ -16,12 +16,16 @@ import java.io.*;
*/
public class GrammarAST {
+ public static interface ImportResolver {
+ public InputStream getImportStream(String importname);
+ }
+
/**
* Returns a Union representing the metagrammar (meta.g); the Tree produced by
* parsing with this Union should be provided to buildFromAST
*/
public static Union getMetaGrammar() {
- return MetaGrammar.newInstance();
+ return buildFromAST(MetaGrammar.meta, "s", null);
}
/**
@@ -31,8 +35,8 @@ public class GrammarAST {
* @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
@@ -40,11 +44,11 @@ public class GrammarAST {
// 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 //////////////////////////////////////////////////////////////////////////////
@@ -107,7 +111,7 @@ public class GrammarAST {
if (head.equals("!")) return new DropNode(walkElement(t.child(0)));
if (head.equals("^")) return new LiteralNode(walkString(t.child(0)), true);
- if (head.equals("`")) return walkElement(t.child(0)).lifted();
+ if (head.equals("`")) return new BacktickNode(walkElement(t.child(0)));
if (head.equals("Quoted")) return stringifyChildren(t);
if (head.equals("Literal")) return new LiteralNode(walkString(t.child(0)));
if (head.equals("->")) return walkSeq(t.child(0)).follow(walkElement(t.child(1)));
@@ -133,8 +137,9 @@ public class GrammarAST {
}
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);
@@ -147,20 +152,21 @@ public class GrammarAST {
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);
- Tree tr = new CharParser(MetaGrammar.newInstance()).parse(fis).expand1();
- return (GrammarNode)new GrammarAST(includes, newPrefix).walk(tr);
+ 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(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("...")));
}
@@ -207,19 +213,26 @@ public class GrammarAST {
}
}
+ /** a node in the AST which is resolved into an Element */
private abstract class ElementNode {
- public boolean lifted = false;
- public Seq ownerSeq = null;
- public ElementNode lifted() { this.lifted = true; return this; }
- public boolean drop(Context cx) { return false; }
+ public boolean isLifted() { 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) {
@@ -227,10 +240,10 @@ public class GrammarAST {
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;
}
@@ -279,10 +292,11 @@ public class GrammarAST {
}
}
+ /** 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;
@@ -291,21 +305,27 @@ public class GrammarAST {
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 and = new HashSet();
+ /** negative conjuncts */
+ HashSet not = new HashSet();
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 and = new HashSet();
- HashSet not = new HashSet();
- 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) {
@@ -314,7 +334,6 @@ public class GrammarAST {
for(int i=0; i)_e.toAtom(cx).complement()); }
@@ -512,7 +543,7 @@ public class GrammarAST {
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; }
}
//////////////////////////////////////////////////////////////////////////////
@@ -542,7 +573,7 @@ public class GrammarAST {
} 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;
}