UnwrapLeft, error reporting improvements

[sbp.git] / src / edu / berkeley / sbp / GSS.java

diff --git a/src/edu/berkeley/sbp/GSS.java b/src/edu/berkeley/sbp/GSS.java
index ca8e1d5..a726297 100644 (file)
--- a/src/edu/berkeley/sbp/GSS.java
+++ b/src/edu/berkeley/sbp/GSS.java
@@ -52,7 +52,6 @@ class GSS {
         private Phase prev;
         private Input.Location location;
         private Input.Location nextLocation;
-        private Input.Location prevLocation;
         
         private Forest forest;
 
@@ -62,13 +61,12 @@ class GSS {
             newNode(primordealResult, startState, true);
         }
         public Phase(Phase prev, Forest forest) throws ParseFailed, IOException {
-            this.prevLocation = input.getLocation();
-            this.token = (Tok)input.next();
             this.location = input.getLocation();
+            this.token = (Tok)input.next();
+            this.nextLocation = input.getLocation();
             this.prev = prev;
             this.forest = forest;
             this.pos = prev==null ? 0 : prev.pos+1;
-            this.nextLocation = input.getLocation();
             if (prev != null) prev.shift(this, forest);
             numReductions = 0;
 
@@ -107,13 +105,12 @@ class GSS {
         public boolean isDone() throws ParseFailed {
             if (token != null) return false;
             if (token==null && finalResult==null)
-                ParseFailed.error("unexpected end of file", this);
+                ParseFailed.error("unexpected end of file", this, null,
+                                  getLocation().createRegion(getLocation()));
             return true;
         }
 
-        public Input.Location getPrevLocation() { return prevLocation; }
         public Input.Location getLocation() { return location; }
-        public Input.Region getRegion() { return prevLocation.createRegion(location); }
         public Input.Location getNextLocation() { return nextLocation; }
         public boolean        isFrontier() { return hash!=null; }
 
@@ -125,8 +122,7 @@ class GSS {
                 IntPairMap<Node> h = prev.hash;
                 prev.hash = null;
                 prev.performed = null;
-                for(Node n : h)
-                    n.check();
+                for(Node n : h) n.check();
             }
             numOldNodes = hash.size();
             for(Node n : hash.values()) {
@@ -140,11 +136,30 @@ class GSS {
             }
             numNewNodes = next==null ? 0 : next.hash.size();
             viewPos = this.pos;
-            if (!good && token!=null) ParseFailed.error("unexpected character", this);
-            if (token==null && finalResult==null) ParseFailed.error("unexpected end of file", this);
+            if (!good && token!=null) {
+                String toks = token+"";
+                if (toks.length()==1 && toks.charAt(0) == edu.berkeley.sbp.chr.CharAtom.left) {
+                    ParseFailed.error("unexpected increase in indentation", this,
+                                      token, getRegionFromThisToNext());
+                } else if (toks.length()==1 && toks.charAt(0) == edu.berkeley.sbp.chr.CharAtom.right) {
+                    ParseFailed.error("unexpected decrease in indentation", this,
+                                      token, getRegionFromThisToNext());
+                } else {
+                    ParseFailed.error("unexpected character '"+ANSI.cyan(StringUtil.escapify(token+"",
+                                                                                             "\\\'\r\n"))+"'",
+                                      this, token, getRegionFromThisToNext());
+                }
+            }
+            if (token==null && finalResult==null)
+                ParseFailed.error("unexpected end of file", this, null,
+                                  getLocation().createRegion(getLocation()));
             for(Node n : hash) n.check();
         }
 
+        Input.Region getRegionFromThisToNext() {
+            return getLocation().createRegion(getNextLocation());
+        }
+
         void newNodeFromReduction(Result result, State state, Position reduction) {
             int pos = result.phase().pos;
             Sequence owner = reduction.owner();
@@ -169,7 +184,7 @@ class GSS {
          */
         private boolean newNode(Result result, State state, boolean fromEmptyReduction) {
             Node p = hash.get(state, result.phase());
-            if (p != null) { p.addResult(result); return true; }
+            if (p != null) { p.addResult(result); return !state.doomed(); }
             do {
                 if (token != null && state.canShift(token)) break;
                 if (state.isAccepting()) break;
@@ -179,7 +194,7 @@ class GSS {
             Node n = new Node(Phase.this, result, state, fromEmptyReduction);  // ALLOC
             for(Object s : state.conjunctStates)
                 newNode(new Result(null, n, null), (State)s, fromEmptyReduction);
-            return true;
+            return !n.state().doomed();
         }
 
         public int toInt() { return pos+1; }