Add some character class tests.

Author: pschachte

wybelibs/wybe/char.wybe

@@ -46,6 +46,19 @@ pub def fmt(x:_, minlength:int):string = fmt(x, minlength, ' ')
 pub def fmt(x:_, minlength:int, fill:_):string =
     fmt(string(x), minlength, fill)
 
+pub def {test} is_whitespace(x:_) {
+    x = ' ' | x = '\t' | x = '\n' | x = '\r' | x = '\f' | x = '\v'
+}
+
+pub def {test} is_digit(x:_) { x >= '0' & x <= '9' }
+
+pub def {test} is_upper(x:_) { x >= 'A' & x <= 'Z' }
+
+pub def {test} is_lower(x:_) { x >= 'a' & x <= 'z' }
+
+pub def {test} is_alpha(x:_) { is_upper(x) | is_lower(x) }
+
+pub def {test} is_alphanumeric(x:_) { is_alpha(x) | is_digit(x) }
 
 ## I/O