From: Tianyi Liang <tianyi-liang@uiowa.edu>
Date: Fri, 31 Jan 2014 18:22:07 +0000 (-0600)
Subject: Substr fix: (= (str.substr "" 0 3) "xxx") should be SAT in the defintion of SMT-Lib
X-Git-Tag: cvc5-1.0.0~7109
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2fda1f59b3f5c5d0d6d9b36ae206b8984fb6064c;p=cvc5.git

Substr fix: (= (str.substr "" 0 3) "xxx") should be SAT in the defintion of SMT-Lib
---

diff --git a/src/theory/strings/theory_strings.cpp b/src/theory/strings/theory_strings.cpp
index d0876d983..58344964c 100644
--- a/src/theory/strings/theory_strings.cpp
+++ b/src/theory/strings/theory_strings.cpp
@@ -54,8 +54,8 @@ TheoryStrings::TheoryStrings(context::Context* c, context::UserContext* u, Outpu
     d_equalityEngine.addFunctionKind(kind::STRING_LENGTH);
     d_equalityEngine.addFunctionKind(kind::STRING_CONCAT);
     d_equalityEngine.addFunctionKind(kind::STRING_STRCTN);
-    d_equalityEngine.addFunctionKind(kind::STRING_CHARAT);
-    d_equalityEngine.addFunctionKind(kind::STRING_SUBSTR);
+    //d_equalityEngine.addFunctionKind(kind::STRING_CHARAT);
+    //d_equalityEngine.addFunctionKind(kind::STRING_SUBSTR);
 
     d_zero = NodeManager::currentNM()->mkConst( Rational( 0 ) );
     d_one = NodeManager::currentNM()->mkConst( Rational( 1 ) );
@@ -1725,20 +1725,6 @@ void TheoryStrings::getConcatVec( Node n, std::vector< Node >& c ) {
 bool TheoryStrings::checkSimple() {
   bool addedLemma = false;
 
-  //Initialize UF
-  if(d_undefSubstr.isNull()) {
-	std::vector< TypeNode > argTypes;
-	argTypes.push_back(NodeManager::currentNM()->stringType());
-	argTypes.push_back(NodeManager::currentNM()->integerType());
-	argTypes.push_back(NodeManager::currentNM()->integerType());
-	d_undefSubstr = NodeManager::currentNM()->mkSkolem("__undefSS", 
-						NodeManager::currentNM()->mkFunctionType(
-							argTypes, NodeManager::currentNM()->stringType()),
-						"undefined substr",
-						NodeManager::SKOLEM_EXACT_NAME);
-  }
-
-
   eq::EqClassesIterator eqcs_i = eq::EqClassesIterator( &d_equalityEngine );
   while( !eqcs_i.isFinished() ) {
 	Node eqc = (*eqcs_i);
@@ -1780,7 +1766,7 @@ bool TheoryStrings::checkSimple() {
 							} else if( n.getKind() == kind::CONST_STRING ) {
 								//add lemma
 								lsum = NodeManager::currentNM()->mkConst( ::CVC4::Rational( n.getConst<String>().size() ) );
-							} else if( n.getKind() == kind::STRING_CHARAT ) {
+							} /*else if( n.getKind() == kind::STRING_CHARAT ) {
 								lsum = d_one;
 								Node sk1 = NodeManager::currentNM()->mkSkolem( "ca1_$$", NodeManager::currentNM()->stringType(), "created for charat" );
 								Node sk3 = NodeManager::currentNM()->mkSkolem( "ca3_$$", NodeManager::currentNM()->stringType(), "created for charat" );
@@ -1788,12 +1774,11 @@ bool TheoryStrings::checkSimple() {
 								Node lenxgti = NodeManager::currentNM()->mkNode( kind::GT, 
 													NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, n[0] ), n[1] );
 								Node t1greq0 = NodeManager::currentNM()->mkNode( kind::GEQ, n[1], d_zero);
+								Node cond = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::AND, lenxgti, t1greq0 ));
 								Node x_eq_123 = n[0].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_CONCAT, sk1, sk, sk3 ) );
 								Node len_sk1_eq_i = n[1].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, sk1 ) );
-								Node cond = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::AND, lenxgti, t1greq0 ));
 								Node lemma = NodeManager::currentNM()->mkNode( kind::AND, x_eq_123, len_sk1_eq_i );
-								Node uf = sk.eqNode( NodeManager::currentNM()->mkNode(kind::APPLY_UF, d_undefSubstr, n[0], n[1], d_one));
-								lemma = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::ITE, cond, lemma, uf) );
+								lemma = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::IMPLIES, cond, lemma ) );
 								Trace("strings-lemma") << "Strings::Lemma CHARAT : " << lemma << std::endl;
 								d_out->lemma(lemma);
 							} else if( n.getKind() == kind::STRING_SUBSTR ) {
@@ -1807,16 +1792,14 @@ bool TheoryStrings::checkSimple() {
 								Node t1geq0 = NodeManager::currentNM()->mkNode(kind::GEQ, n[1], d_zero);
 								Node t2geq0 = NodeManager::currentNM()->mkNode(kind::GEQ, n[2], d_zero);
 								Node x_eq_123 = n[0].eqNode(NodeManager::currentNM()->mkNode( kind::STRING_CONCAT, sk1, sk, sk3 ));
+								Node cond = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::AND, lenxgti, t1geq0, t2geq0 ));
 								Node len_sk1_eq_i = NodeManager::currentNM()->mkNode( kind::EQUAL, n[1],
 														NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, sk1 ) );
-
 								Node lemma = NodeManager::currentNM()->mkNode( kind::AND, x_eq_123, len_sk1_eq_i );
-								Node cond = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::AND, lenxgti, t1geq0, t2geq0 ));
-								Node uf = sk.eqNode( NodeManager::currentNM()->mkNode(kind::APPLY_UF, d_undefSubstr, n[0], n[1], n[2]));
-								lemma = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::ITE, cond, lemma, uf ) );
+								lemma = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::IMPLIES, cond, lemma ) );
 								Trace("strings-lemma") << "Strings::Lemma SUBSTR : " << lemma << std::endl;
 								d_out->lemma(lemma);
-							}
+							}*/
 							Node ceq = NodeManager::currentNM()->mkNode( kind::EQUAL, skl, lsum );
 							ceq = Rewriter::rewrite(ceq);
 							Trace("strings-lemma") << "Strings::Lemma LENGTH : " << ceq << std::endl;
@@ -2409,6 +2392,18 @@ bool TheoryStrings::checkPosContains() {
 }
 
 bool TheoryStrings::checkNegContains() {
+	//Initialize UF
+	if(d_ufSubstr.isNull()) {
+		std::vector< TypeNode > argTypes;
+		argTypes.push_back(NodeManager::currentNM()->stringType());
+		argTypes.push_back(NodeManager::currentNM()->integerType());
+		argTypes.push_back(NodeManager::currentNM()->integerType());
+		d_ufSubstr = NodeManager::currentNM()->mkSkolem("__ufSS", 
+							NodeManager::currentNM()->mkFunctionType(
+								argTypes, NodeManager::currentNM()->stringType()),
+							"uf substr",
+							NodeManager::SKOLEM_EXACT_NAME);
+	}
 	bool is_unk = false;
 	bool addedLemma = false;
 	for( unsigned i=0; i<d_str_neg_ctn.size(); i++ ){
@@ -2450,8 +2445,10 @@ bool TheoryStrings::checkNegContains() {
 							Node g1 = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::AND, NodeManager::currentNM()->mkNode( kind::GEQ, b1, d_zero ),
 										NodeManager::currentNM()->mkNode( kind::GEQ, NodeManager::currentNM()->mkNode( kind::MINUS, lenx, lens ), b1 ) ) );
 							Node b2 = NodeManager::currentNM()->mkBoundVar("bj", NodeManager::currentNM()->integerType());
-							Node s2 = NodeManager::currentNM()->mkNode(kind::STRING_CHARAT, x, NodeManager::currentNM()->mkNode( kind::PLUS, b1, b2 ));
-							Node s5 = NodeManager::currentNM()->mkNode(kind::STRING_CHARAT, s, b2);
+							//Node s2 = NodeManager::currentNM()->mkNode(kind::STRING_CHARAT, x, NodeManager::currentNM()->mkNode( kind::PLUS, b1, b2 ));
+							//Node s5 = NodeManager::currentNM()->mkNode(kind::STRING_CHARAT, s, b2);
+							Node s2 = NodeManager::currentNM()->mkNode(kind::APPLY_UF, d_ufSubstr, x, NodeManager::currentNM()->mkNode( kind::PLUS, b1, b2 ), d_one);
+							Node s5 = NodeManager::currentNM()->mkNode(kind::APPLY_UF, d_ufSubstr, s, b2, d_one);
 
 							Node s1 = NodeManager::currentNM()->mkBoundVar("s1", NodeManager::currentNM()->stringType());
 							Node s3 = NodeManager::currentNM()->mkBoundVar("s3", NodeManager::currentNM()->stringType());
@@ -2476,6 +2473,12 @@ bool TheoryStrings::checkNegContains() {
 							cc = NodeManager::currentNM()->mkNode(kind::STRING_LENGTH, s4).eqNode(b2);
 							vec_nodes.push_back(cc);
 
+							// charAt length
+							cc = d_one.eqNode(NodeManager::currentNM()->mkNode(kind::STRING_LENGTH, s2));
+							vec_nodes.push_back(cc);
+							cc = d_one.eqNode(NodeManager::currentNM()->mkNode(kind::STRING_LENGTH, s5));
+							vec_nodes.push_back(cc);
+
 							Node conc = Rewriter::rewrite( NodeManager::currentNM()->mkNode(kind::AND, vec_nodes) );
 							Node xlss = NodeManager::currentNM()->mkNode( kind::GT, lens, lenx );
 							conc = NodeManager::currentNM()->mkNode( kind::OR, xlss, conc );
diff --git a/src/theory/strings/theory_strings.h b/src/theory/strings/theory_strings.h
index 05e6ebf71..5d8ff016f 100644
--- a/src/theory/strings/theory_strings.h
+++ b/src/theory/strings/theory_strings.h
@@ -115,7 +115,7 @@ private:
     Node d_false;
     Node d_zero;
 	Node d_one;
-	Node d_undefSubstr;
+	Node d_ufSubstr;
 	// Options
 	bool d_all_warning;
 	bool d_opt_fmf;
diff --git a/src/theory/strings/theory_strings_preprocess.cpp b/src/theory/strings/theory_strings_preprocess.cpp
index ae5303d9d..707fae459 100644
--- a/src/theory/strings/theory_strings_preprocess.cpp
+++ b/src/theory/strings/theory_strings_preprocess.cpp
@@ -127,18 +127,35 @@ Node StringsPreprocess::simplify( Node t, std::vector< Node > &new_nodes ) {
       return (*i).second.isNull() ? t : (*i).second;
     }
 
+	//Initialize UF
+	if(d_ufSubstr.isNull()) {
+		std::vector< TypeNode > argTypes;
+		argTypes.push_back(NodeManager::currentNM()->stringType());
+		argTypes.push_back(NodeManager::currentNM()->integerType());
+		argTypes.push_back(NodeManager::currentNM()->integerType());
+		d_ufSubstr = NodeManager::currentNM()->mkSkolem("__ufSS", 
+							NodeManager::currentNM()->mkFunctionType(
+								argTypes, NodeManager::currentNM()->stringType()),
+							"uf substr",
+							NodeManager::SKOLEM_EXACT_NAME);
+	}
+
 	Trace("strings-preprocess") << "StringsPreprocess::simplify: " << t << std::endl;
 	Node retNode = t;
-	int c_id = checkFixLenVar(t);
+	/*int c_id = checkFixLenVar(t);
 	if( c_id != 2 ) {
 		int v_id = 1 - c_id;
 		int len = t[c_id].getConst<Rational>().getNumerator().toUnsignedInt();
 		if(len > 1) {
+			Node one = NodeManager::currentNM()->mkConst( ::CVC4::Rational(1) );
 			std::vector< Node > vec;
 			for(int i=0; i<len; i++) {
 				Node num = NodeManager::currentNM()->mkConst( ::CVC4::Rational(i) );
-				Node sk = NodeManager::currentNM()->mkNode(kind::STRING_CHARAT, t[v_id][0], num);
+				//Node sk = NodeManager::currentNM()->mkNode(kind::STRING_CHARAT, t[v_id][0], num);
+				Node sk = NodeManager::currentNM()->mkNode(kind::APPLY_UF, d_ufSubstr, t[v_id][0], num, one);
 				vec.push_back(sk);
+				Node cc = one.eqNode(NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, sk ));
+				new_nodes.push_back( cc );
 			}
 			Node lem = t[v_id][0].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_CONCAT, vec ) );
 			lem = NodeManager::currentNM()->mkNode( kind::IMPLIES, t, lem );
@@ -146,7 +163,7 @@ Node StringsPreprocess::simplify( Node t, std::vector< Node > &new_nodes ) {
 			d_cache[t] = t;
 			retNode = t;
 		}
-	} else if( t.getKind() == kind::STRING_IN_REGEXP ) {
+	} else */if( t.getKind() == kind::STRING_IN_REGEXP ) {
 		// t0 in t1
 		Node t0 = simplify( t[0], new_nodes );
 		
@@ -164,7 +181,42 @@ Node StringsPreprocess::simplify( Node t, std::vector< Node > &new_nodes ) {
 			// TODO
 		//	return (t0 == t[0]) ? t : NodeManager::currentNM()->mkNode( kind::STRING_IN_REGEXP, t0, t[1] );
 		//}
-	} else if( t.getKind() == kind::STRING_STRIDOF ){
+	} else if( t.getKind() == kind::STRING_CHARAT ) {
+		Node lenxgti = NodeManager::currentNM()->mkNode( kind::GT, 
+							NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, t[0] ), t[1] );
+		Node t1greq0 = NodeManager::currentNM()->mkNode( kind::GEQ, t[1], d_zero);
+		Node cond = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::AND, lenxgti, t1greq0 ));
+		Node one = NodeManager::currentNM()->mkConst( ::CVC4::Rational(1) );
+		Node uf = NodeManager::currentNM()->mkNode(kind::APPLY_UF, d_ufSubstr, t[0], t[1], one);
+		Node sk1 = NodeManager::currentNM()->mkSkolem( "ss1_$$", NodeManager::currentNM()->stringType(), "created for charat/substr" );
+		Node sk3 = NodeManager::currentNM()->mkSkolem( "ss3_$$", NodeManager::currentNM()->stringType(), "created for charat/substr" );
+		Node x_eq_123 = t[0].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_CONCAT, sk1, uf, sk3 ) );
+		Node len_sk1_eq_i = t[1].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, sk1 ) );
+		Node len_uf_eq_j = one.eqNode( NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, uf ) );
+		Node lemma = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::IMPLIES, cond, 
+						NodeManager::currentNM()->mkNode( kind::AND, x_eq_123, len_sk1_eq_i, len_uf_eq_j )) );
+		new_nodes.push_back( lemma );
+		retNode = uf;
+		d_cache[t] = uf;
+	} else if( t.getKind() == kind::STRING_SUBSTR ) {
+		Node lenxgti = NodeManager::currentNM()->mkNode( kind::GEQ, 
+							NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, t[0] ),
+							NodeManager::currentNM()->mkNode( kind::PLUS, t[1], t[2] ) );
+		Node t1geq0 = NodeManager::currentNM()->mkNode(kind::GEQ, t[1], d_zero);
+		Node t2geq0 = NodeManager::currentNM()->mkNode(kind::GEQ, t[2], d_zero);
+		Node cond = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::AND, lenxgti, t1geq0, t2geq0 ));
+		Node uf = NodeManager::currentNM()->mkNode(kind::APPLY_UF, d_ufSubstr, t[0], t[1], t[2]);
+		Node sk1 = NodeManager::currentNM()->mkSkolem( "ss1_$$", NodeManager::currentNM()->stringType(), "created for charat/substr" );
+		Node sk3 = NodeManager::currentNM()->mkSkolem( "ss3_$$", NodeManager::currentNM()->stringType(), "created for charat/substr" );
+		Node x_eq_123 = t[0].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_CONCAT, sk1, uf, sk3 ) );
+		Node len_sk1_eq_i = t[1].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, sk1 ) );
+		Node len_uf_eq_j = t[2].eqNode( NodeManager::currentNM()->mkNode( kind::STRING_LENGTH, uf ) );
+		Node lemma = Rewriter::rewrite( NodeManager::currentNM()->mkNode( kind::IMPLIES, cond, 
+						NodeManager::currentNM()->mkNode( kind::AND, x_eq_123, len_sk1_eq_i, len_uf_eq_j )) );
+		new_nodes.push_back( lemma );
+		retNode = uf;
+		d_cache[t] = uf;
+	} else if( t.getKind() == kind::STRING_STRIDOF ) {
 		if(options::stringExp()) {
 			Node sk1 = NodeManager::currentNM()->mkSkolem( "io1_$$", t[0].getType(), "created for indexof" );
 			Node sk2 = NodeManager::currentNM()->mkSkolem( "io2_$$", t[0].getType(), "created for indexof" );
diff --git a/src/theory/strings/theory_strings_preprocess.h b/src/theory/strings/theory_strings_preprocess.h
index 630c7595c..a8074861e 100644
--- a/src/theory/strings/theory_strings_preprocess.h
+++ b/src/theory/strings/theory_strings_preprocess.h
@@ -31,7 +31,9 @@ namespace strings {
 class StringsPreprocess {
 	// NOTE: this class is NOT context-dependent
 	std::hash_map<TNode, Node, TNodeHashFunction> d_cache;
+	//Constants
 	Node d_zero;
+	Node d_ufSubstr;
 private:
 	bool checkStarPlus( Node t );
 	int checkFixLenVar( Node t );