simplify mkSkolem naming system: don't use $$

Short summary: By default NODEID is appeneded, just continue doing what you
were, just don't add the _$$ at the end.

Long summary:

Before this commit there were four (yes!) ways to specify the names for new
skolems, which result in names as given below

1) mkSkolem("name", ..., SKOLEM_FLAG_DEFAULT)  -> "name_NODEID"
2) mkSkolem("name", ..., SKOLEM_EXACT_NAME)  -> "name"
3) mkSkolem("name_$$", ..., SKOLEM_FLAG_DEFAULT) -> "name_NODEID"
4) mkSkolem("na_$$_me", ..., SKOLEM_FLAG_DEFAULT) -> "na_NODEID_me"

After this commit, only 1) and 2) stay.

90% usage is of 1) or 3), which results in exact same behavior (and
looking at the source code it doesn't look like everyone realized that
the _$$ is just redundant).

Almost no one used 4), which is the only reason to even have $$. Post this
commit if you really want a number in the middle, manually construct the
name and use the SKOLEM_EXACT_NAME flag.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/theory/strings/regexp_operation.cpp b/src/theory/strings/regexp_operation.cpp
index d719b4e1a..8c07b679d 100644
--- a/src/theory/strings/regexp_operation.cpp
+++ b/src/theory/strings/regexp_operation.cpp
@@ -296,7 +296,7 @@ int RegExpOpr::derivativeS( Node r, CVC4::String c, Node &retNode ) {
 						}

 					}

 					if(ret == 0) {

-						Node sk = NodeManager::currentNM()->mkSkolem( "rsp_$$", NodeManager::currentNM()->stringType(), "Split RegExp" );

+						Node sk = NodeManager::currentNM()->mkSkolem( "rsp", NodeManager::currentNM()->stringType(), "Split RegExp" );

 						retNode = NodeManager::currentNM()->mkNode(kind::STRING_TO_REGEXP, sk);

 						if(!rest.isNull()) {

 							retNode = Rewriter::rewrite(NodeManager::currentNM()->mkNode(kind::REGEXP_CONCAT, retNode, rest));

@@ -1038,7 +1038,7 @@ void RegExpOpr::simplifyPRegExp( Node s, Node r, std::vector< Node > &new_nodes
 						emptyflag = true;

 						break;

 					} else {

-						Node sk = NodeManager::currentNM()->mkSkolem( "rc_$$", s.getType(), "created for regular expression concat" );

+						Node sk = NodeManager::currentNM()->mkSkolem( "rc", s.getType(), "created for regular expression concat" );

 						Node lem = NodeManager::currentNM()->mkNode(kind::STRING_IN_REGEXP, sk, r[i]);

 						nvec.push_back(lem);

 						cc.push_back(sk);

@@ -1098,8 +1098,8 @@ void RegExpOpr::simplifyPRegExp( Node s, Node r, std::vector< Node > &new_nodes
 				} else {

 					Node se = s.eqNode(d_emptyString);

 					Node sinr = NodeManager::currentNM()->mkNode(kind::STRING_IN_REGEXP, s, r[0]);

-					Node sk1 = NodeManager::currentNM()->mkSkolem( "rs_$$", s.getType(), "created for regular expression star" );

-					Node sk2 = NodeManager::currentNM()->mkSkolem( "rs_$$", s.getType(), "created for regular expression star" );

+					Node sk1 = NodeManager::currentNM()->mkSkolem( "rs", s.getType(), "created for regular expression star" );

+					Node sk2 = NodeManager::currentNM()->mkSkolem( "rs", s.getType(), "created for regular expression star" );

 					Node s1nz = sk1.eqNode(d_emptyString).negate();

 					Node s2nz = sk2.eqNode(d_emptyString).negate();

 					Node s1inr = NodeManager::currentNM()->mkNode(kind::STRING_IN_REGEXP, sk1, r[0]);