Support the SMT-LIB Unicode string standard by default (#4378)

This PR merges --lang=smt2.6.1 and --lang=smt2.6 (default). It makes it so that 2.6 always expects the syntax of the string standard http://smtlib.cs.uiowa.edu/theories-UnicodeStrings.shtml.

I've updated the regressions so that the 2.6 benchmarks are now compliant with the standard. Some of the <=2.5 benchmarks I've updated to 2.6. Others I have left for now, in particular the ones that rely on special characters or ad-hoc escape sequences. The old formats will be supported in the release but removed shortly afterwards.

This PR is a prerequisite for the release, but not necessarily SMT-COMP (which will use --lang=smt2.6.1 if needed). Notice that we still do not have parsing support for str.replace_re or str.replace_re_all. This is required to be fully compliant.

1 files changed, 8 insertions, 8 deletions

diff --git a/test/regress/regress1/strings/str-code-sat.smt2 b/test/regress/regress1/strings/str-code-sat.smt2
index 1acc091c1..7345e25bb 100644
--- a/test/regress/regress1/strings/str-code-sat.smt2
+++ b/test/regress/regress1/strings/str-code-sat.smt2
@@ -5,19 +5,19 @@
 (declare-fun z () String)
 (declare-fun w () String)
 
-(assert (>= (str.code x) 65))
-(assert (<= (str.code x) 75))
+(assert (>= (str.to_code x) 65))
+(assert (<= (str.to_code x) 75))
 
-(assert (>= (str.code y) 65))
-(assert (<= (str.code y) 75))
+(assert (>= (str.to_code y) 65))
+(assert (<= (str.to_code y) 75))
 
-(assert (>= (str.code z) 65))
-(assert (<= (str.code z) 75))
+(assert (>= (str.to_code z) 65))
+(assert (<= (str.to_code z) 75))
 
 (assert (= (str.len w) 1))
 
-(assert (= (+ (str.code x) (str.code y)) 140))
-(assert (= (+ (str.code x) (str.code z)) 141))
+(assert (= (+ (str.to_code x) (str.to_code y)) 140))
+(assert (= (+ (str.to_code x) (str.to_code z)) 141))
 
 (assert (distinct x y z w "A" "B" "C" "D" "AA"))