X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmeta%2FGrammarAST.java;h=ed8fe9450469071d6548c6ebd2f026ee25aba548;hb=c404939a6dfed4dcfdca5ede08db99b3e5ef0c91;hp=05c7b39dc7394dac4cc448b59f5a6dbc70f76422;hpb=013262fd96a3dfc4c2cd7a0ba320dd7981ce678c;p=sbp.git
diff --git a/src/edu/berkeley/sbp/meta/GrammarAST.java b/src/edu/berkeley/sbp/meta/GrammarAST.java
index 05c7b39..ed8fe94 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("...")));
}
@@ -207,11 +213,10 @@ 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);
}
@@ -227,10 +232,10 @@ 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;
}
@@ -282,7 +287,7 @@ public class GrammarAST {
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;
@@ -293,11 +298,11 @@ public class GrammarAST {
private class 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)_e.toAtom(cx).complement()); }
@@ -512,7 +521,7 @@ 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 +551,7 @@ 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;
}