Initial import of the ircii-pana-1.1-final source tree.

git-svn-id: svn://svn.code.sf.net/p/bitchx/code/tags/ircii-pana-1.1-final@1 13b04d17-f746-0410-82c6-800466cd88b0

dll/europa/cse476/gnode.cpp

@@ -0,0 +1,230 @@
+// Copyright (c) 1998-99, Ed Schlunder
+
+#include <string.h>
+#include "gnode.h"
+#include "list.h"
+
+// takes a string and hacks off leading/trailing spaces and *'s.
+void trim(char *text) {
+  int i, j, len;
+
+  len = strlen(text);
+
+  // empty strings don't need trimming...
+  if(len == 0) return;
+
+  // find beginning of actual text
+  for(i = 0; i < len; i++)
+    if(text[i] != ' ') break;
+
+  // was there any preceeding white space to clear out?
+  if(i > 0)
+    for(j = 0; text[i] != 0; j++, i++)
+      text[j] = text[i];
+
+  // step from the end backwards to see find where we need to chop
+  for(j = strlen(text); j > 1; j--)
+    if(text[j-1] != ' ') {
+      text[j] = 0;
+      break;
+    }
+}
+
+
+// ---------------------------------------------------------------------------
+// Class Implementation: genericNode
+// ---------------------------------------------------------------------------
+
+genericNode::genericNode(char *word, List *features) {
+  if(word) {
+    name = new char[strlen(word)];
+    strcpy(name, word);
+  }
+  else
+    word = NULL;
+
+  featureList = features;
+}
+
+// Example Phrasal: ((CAT N) (AGR ?a))
+// Example Lexical: saw ((CAT N) (ROOT SAW1) (AGR 3s))
+genericNode::genericNode(char *obj) {
+  unsigned int i, j;
+
+  // first try to read in the name field (in lexical objects)
+  for(i = 0; i < strlen(obj); i++)
+    if(obj[i] != ' ') break;
+  
+  // maybe this is a phrasal object -- doesn't have a "name" field
+  if(obj[i] == '(') {
+    name = NULL;
+    j = i;
+  }
+  else {
+    // this is a lexical object, pick up the name:
+    for(j = i; j < strlen(obj); j++)
+      if(obj[j] == ' ') break;
+    
+    name = new char[j - i + 1];
+    strncpy(name, obj, j - i);
+    name[j - i] = 0;
+    j++;
+  }
+
+  // pick up the object's feature list
+  char *tmp = obj + j;
+  //  cout << "[" << tmp << "]" << endl;
+  featureList = makeFeatureList(tmp);
+}
+
+ostream& operator<<(ostream &out_file, genericNode const &n) {
+  if(n.name == NULL)
+    out_file << "(nil";
+  else
+    out_file << '(' << n.name;
+
+  if(n.featureList)
+    out_file << ' ' << *n.featureList;
+
+  out_file << ')';
+
+  return out_file;
+}
+
+List *unify(genericNode &s, genericNode &g) {
+  List &sFeatures = *s.featureList, &gFeatures = *g.featureList, *currFeature;
+  List *assignList = new List;
+  char *featureName;
+  List *featureValueA, *featureValueB;
+
+  // if a node has no feature list, then we automatically know it can unify
+  if(!sFeatures.GoTop()) return new List;
+  if(!gFeatures.GoTop()) return new List;
+  
+  do {
+    // get the current feature
+    currFeature = sFeatures.currItemList();
+    currFeature->GoTop();
+
+    // pull out the feature name and value
+    featureName = currFeature->currItem();
+    currFeature->GoNext();
+    featureValueA = currFeature->currItemList();
+    featureValueB = g.lookupFeature(featureName);
+
+    /*
+    cout << "unify: [" << featureName << "] = " << *featureValueA << "";
+    cout << " with " << *featureValueB << " --> ";
+    */
+
+    /*
+    if(featureValueB == NULL)
+      // if feature lookup failed, no corresponding feature exists -- 
+      // automatically agrees...
+      //      cout << "yes" << endl;
+    else {
+    */
+    // if featureB is nothing, no corresponding featuture exists -- agrees
+    if(featureValueB != NULL) {
+      List *assignment = cmpFeatures(*featureValueA, *featureValueB);
+      if(assignment == NULL) {
+	//	cout << "no" << endl;
+	delete assignList;
+	return NULL;
+      }
+      //      cout << "yes: " << *assignment << endl;
+      if(!assignment->empty())
+	assignList->InsertAfter(assignment);
+    }
+  } while(sFeatures.GoNext());
+  //  cout << "assignment list: " << *assignList << endl;
+  return assignList;
+}
+
+List *cmpFeatures(List &a, List &b) {
+  char *valueA, *valueB;
+  a.GoTop();
+
+  do {
+    valueA = a.currItem();
+
+    b.GoTop();
+    do {
+      valueB = b.currItem();
+
+      // do we have a match?
+      if(strcmp(valueA, valueB) == 0)
+	return new List;
+
+      // if one of the values is a variable, then it can match anything
+      if(valueA[0] == '?') {
+	List *assignList = new List;
+	assignList->InsertAfter(valueA);
+	assignList->InsertAfter(&b);
+
+	return assignList;
+      }
+
+      if(valueB[0] == '?') {
+	List *assignList = new List;
+	assignList->InsertAfter(valueB);
+	assignList->InsertAfter(&a);
+
+	return assignList;
+      }
+    } while(b.GoNext());
+  } while(a.GoNext());
+
+  return NULL;
+}
+
+List *genericNode::lookupFeature(const char *name) const {
+  char *tmp;
+  List *featureSeek;
+  
+  // if this node has no features, abort search
+  if(featureList == NULL) return NULL;
+
+  featureList->GoTop();
+  do {
+    // pick up current feature
+    featureSeek = featureList->currItemList();
+    featureSeek->GoTop();
+
+    // pick up current feature's name
+    tmp = featureSeek->currItem();
+
+    // is this the feature we were trying to find?
+    if(strcmp(tmp, name) == 0) {
+      // found our feature, pick up the value
+      featureSeek->GoNext();
+      return featureSeek->currItemList();
+    }
+  } while(featureList->GoNext());
+
+  // exhausted the feature list, this feature doesn't exist in this genericNode
+  return NULL;
+}
+
+char *genericNode::word(void) {
+  return name;
+}
+
+genericNode::~genericNode() {
+  // -----------------------
+  // THIS NEEDS IMPLEMENTING
+  // -----------------------
+  delete name;
+  delete featureList;
+}
+
+List *genericNode::features(void) {
+  return featureList;
+}
+// ---------------------------------------------------------------------------
+genericNode *substitute(genericNode *old, List *assign) {
+  genericNode *subst;
+
+  subst = new genericNode(old->name, substitute(old->featureList, assign));
+  return subst;
+}