Improve strings rewriter for contains (#1207)

* Work on rewriter for string contains.

* Add rewrites that mix str.to.int and str.contains. Documentation, add regression.

* Minor

* Minor

* Address review, add a few TODOs. Improve some non-digit -> not is number.

* Fix

* Simplify.

* Clang format, minor fixing of comments.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/util/regexp.cpp b/src/util/regexp.cpp
index 681b574a3..d93c5426e 100644
--- a/src/util/regexp.cpp
+++ b/src/util/regexp.cpp
@@ -357,14 +357,20 @@ bool String::isNumber() const {
     return false;
   }
   for (unsigned character : d_str) {
-    unsigned char c = convertUnsignedIntToChar(character);
-    if (c < '0' || c > '9') {
+    if (!isDigit(character))
+    {
       return false;
     }
   }
   return true;
 }
 
+bool String::isDigit(unsigned character)
+{
+  unsigned char c = convertUnsignedIntToChar(character);
+  return c >= '0' && c <= '9';
+}
+
 int String::toNumber() const {
   if (isNumber()) {
     int ret = 0;