Join() convenience method for strings. Closes #552.

mesonbuild/interpreter.py

@@ -2109,6 +2109,12 @@ class Interpreter():
                 return int(obj)
             except Exception:
                 raise InterpreterException('String can not be converted to int: ' + obj)
+        elif method_name == 'join':
+            if len(posargs) != 1:
+                raise InterpreterException('Join() takes exactly one argument.')
+            strlist = posargs[0]
+            check_stringlist(strlist)
+            return obj.join(strlist)
         raise InterpreterException('Unknown method "%s" for a string.' % method_name)
 
     def to_native(self, arg):

test cases/common/42 string formatting/meson.build

@@ -51,3 +51,7 @@ assert(false.to_string() == 'false', 'bool string conversion failed')
 assert(true.to_string('yes', 'no') == 'yes', 'bool string conversion with args failed')
 assert(false.to_string('yes', 'no') == 'no', 'bool string conversion with args failed')
 assert('@0@'.format(true) == 'true', 'bool string formatting failed')
+
+assert(' '.join(['a', 'b', 'c']) == 'a b c', 'join() array broken')
+assert(''.join(['a', 'b', 'c']) == 'abc', 'empty join() broken')
+assert(' '.join(['a']) == 'a', 'single join broken')