[Strings] Add Char support for whitespace? + minor fixes

src/helpers/strings.nim

@@ -218,4 +218,10 @@ func getSimilar*(s: string, options: seq[string]): seq[string] =
     levs.sort(cmper)
 
     if levs.len > 3: result = toSeq(levs.keys)[0..2]
-    else: result = toSeq(levs.keys)
+    else: result = toSeq(levs.keys)
+
+func isWhitespace*(s: string): bool =
+    if s.len == 0: return false
+    for c in s:
+        if c notin Whitespace: return false
+    return true

src/library/Strings.nim

@@ -969,7 +969,7 @@ proc defineLibrary*() =
         rule        = PrefixPrecedence,
         description = "check if given character/string is in ASCII",
         args        = {
-            "string": {Char,String}
+            "string": {String,Char}
         },
         attrs       = NoAttrs,
         returns     = {Logical},
@@ -1011,6 +1011,9 @@ proc defineLibrary*() =
             lower? "X"               ; => false
             lower? "Hello World"     ; => false
             lower? "hello"           ; => true
+            ..........
+            lower? 'a'               ; => true
+            lower? 'A'               ; => false
         """:
             #=======================================================
             if xKind==Char:
@@ -1175,6 +1178,9 @@ proc defineLibrary*() =
             upper? "x"               ; => false
             upper? "Hello World"     ; => false
             upper? "HELLO"           ; => true
+            ..........
+            upper? 'A'               ; => true
+            upper? 'a'               ; => false
         """:
             #=======================================================
             if xKind==Char:
@@ -1196,18 +1202,25 @@ proc defineLibrary*() =
         rule        = PrefixPrecedence,
         description = "check if given string consists only of whitespace",
         args        = {
-            "string": {String}
+            "string": {String,Char}
         },
         attrs       = NoAttrs,
         returns     = {Logical},
         example     = """
             whitespace? "hello"           ; => false
             whitespace? " "               ; => true
             whitespace? "\n \n"           ; => true
+            whitespace? ""                ; => false
+            ..........
+            whitespace? ' '               ; => true
+            whitespace? '\n'              ; => true
+            whitespace? 'a'               ; => false
         """:
             #=======================================================
-            push(newLogical(x.s.isEmptyOrWhitespace()))
-
+            if xKind==Char:
+                push(newLogical(x.c.isWhitespace()))
+            else:
+                push(newLogical(x.s.isWhitespace()))
 
 #=======================================
 # Add Library